Drug Interactions between bismuth subsalicylate / metronidazole / tetracycline and imipramine

CONTRAINDICATED: Use of alcohol or products containing alcohol during nitroimidazole therapy may result in a disulfiram-like reaction in some patients. There have been a few case reports involving metronidazole, although data overall are not convincing. The presumed mechanism is inhibition of aldehyde dehydrogenase (ALDH) by metronidazole in a manner similar to disulfiram. Following ingestion of alcohol, inhibition of ALDH results in increased concentrations of acetaldehyde, the accumulation of which can produce an unpleasant physiologic response referred to as the 'disulfiram reaction'. Symptoms include flushing, throbbing in head and neck, throbbing headache, respiratory difficulty, nausea, vomiting, sweating, thirst, chest pain, palpitation, dyspnea, hyperventilation, tachycardia, hypotension, syncope, weakness, vertigo, blurred vision, and confusion. Severe reactions may result in respiratory depression, cardiovascular collapse, arrhythmia, myocardial infarction, acute congestive heart failure, unconsciousness, convulsions, and death. However, some investigators have questioned the disulfiram-like properties of metronidazole. One study found neither elevations in blood acetaldehyde nor objective or subjective signs of a disulfiram-like reaction to ethanol in six subjects treated with metronidazole (200 mg three times a day for 5 days) compared to six subjects who received placebo.

MANAGEMENT: Because clear evidence is lacking concerning the safety of ethanol use during nitroimidazole therapy, patients should be apprised of the potential for interaction. Consumption of alcoholic beverages and products containing propylene glycol is specifically contraindicated during and for at least 3 days after completion of metronidazole and benznidazole therapy according to their product labeling.

ADJUST DOSING INTERVAL: Administration with food, particularly dairy products, significantly reduces tetracycline absorption. The calcium content in some foods can form nonabsorbable chelates with tetracycline.

MANAGEMENT: Tetracycline should be administered one hour before or two hours after meals. Because oral tetracycline has caused rare cases of esophagitis and esophageal ulceration, patients should be advised to take tetracycline with a large glass of water while standing or sitting upright and to avoid laying down immediately afterwards.

GENERALLY AVOID: Concomitant use of ethanol and a tricyclic antidepressant (TCA) may result altered TCA plasma levels and efficacy, and additive impairment of motor skills, especially driving skills. Acute ethanol ingestion may inhibit TCA metabolism, while chronic ingestion of large amounts of ethanol may induce hepatic TCA metabolism.

MANAGEMENT: Patients should be advised to avoid alcohol during TCA therapy. Alcoholics who have undergone detoxification should be monitored for decreased TCA efficacy. Dosage adjustments may be required.

GENERALLY AVOID: The oral bioavailability of quinolone and tetracycline antibiotics may be reduced by concurrent administration of preparations containing polyvalent cations such as aluminum, calcium, iron, magnesium, and zinc. Therapeutic failure may result. The proposed mechanism is chelation of quinolone and tetracycline antibiotics by di- and trivalent cations, forming an insoluble complex that is poorly absorbed from the gastrointestinal tract. Reduced gastrointestinal absorption of the cations should also be considered.

MANAGEMENT: Concomitant administration of oral quinolone and tetracycline antibiotics with preparations containing aluminum, calcium, iron, magnesium, and/or zinc salts should generally be avoided. Otherwise, the times of administration should be staggered by as much as possible to minimize the potential for interaction. Quinolones should typically be dosed either 2 to 4 hours before or 4 to 6 hours after polyvalent cation preparations, depending on the quinolone and formulation. Likewise, tetracyclines and polyvalent cation preparations should typically be administered 2 to 4 hours apart. The prescribing information for the antibiotic should be consulted for more specific dosing recommendations.

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.

Tricyclic antidepressants (TCAs), can lower the seizure threshold and trigger seizures. These drugs should be used with extreme caution in patients with a history of seizures, or other predisposing factors, such as head trauma, CNS abnormalities, and alcoholism. Daily dose restrictions might apply for specific antidepressants. Physicians are encouraged to get additional dosing recommendations on the manufacturer's prescribing information.

Tricyclic and tetracyclic antidepressants (TCAs) may cause orthostatic hypotension, reflex tachycardia, syncope, and dizziness, particularly during initiation of therapy or rapid escalation of dosage. Imipramine appears to have the greatest propensity to induce these effects, while secondary amines such as nortriptyline may do so less frequently. Tolerance to the hypotensive effects often develops after a few doses to a few weeks. Rarely, collapse and sudden death have occurred secondary to severe hypotension. Other reported adverse cardiovascular effects include tachycardia, arrhythmias, heart block, hypertension, thrombosis, thrombophlebitis, myocardial infarction, strokes, congestive heart failure, and ECG abnormalities such as PR and QT interval prolongation. Therapy with TCAs should be avoided during the acute recovery phase following myocardial infarction, and should be administered only with extreme caution in patients with hyperthyroidism, a history of cardiovascular or cerebrovascular disease, or a predisposition to hypotension. Close monitoring of cardiovascular status, including ECG changes, is recommended at all dosages. Many of the newer antidepressants, including bupropion and the selective serotonin reuptake inhibitors (SSRIs), are considerably less or minimally cardiotoxic and may be appropriate alternatives.

The use of nitroimidazoles (e.g., metronidazole, tinidazole) has rarely been associated with hematologic adverse effects such as mild, transient leukopenia, thrombocytopenia, and bone marrow aplasia. The manufacturers recommend that therapy with nitroimidazoles be administered cautiously in patients with evidence of or a history of blood dyscrasias, and that total and differential leukocyte counts be performed before and after treatment with these drugs, particularly in patients receiving repeated courses of therapy.

Tricyclic and tetracyclic antidepressants (TCAs) may cause orthostatic hypotension, reflex tachycardia, syncope, and dizziness, particularly during initiation of therapy or rapid escalation of dosage. Imipramine appears to have the greatest propensity to induce these effects, while secondary amines such as nortriptyline may do so less frequently. Tolerance to the hypotensive effects often develops after a few doses to a few weeks. Rarely, collapse and sudden death have occurred secondary to severe hypotension. Other reported adverse cardiovascular effects include tachycardia, arrhythmias, heart block, hypertension, thrombosis, thrombophlebitis, myocardial infarction, strokes, congestive heart failure, and ECG abnormalities such as PR and QT interval prolongation. Therapy with TCAs should be avoided during the acute recovery phase following myocardial infarction, and should be administered only with extreme caution in patients with hyperthyroidism, a history of cardiovascular or cerebrovascular disease, or a predisposition to hypotension. Close monitoring of cardiovascular status, including ECG changes, is recommended at all dosages. Many of the newer antidepressants, including bupropion and the selective serotonin reuptake inhibitors (SSRIs), are considerably less or minimally cardiotoxic and may be appropriate alternatives.

Tricyclic antidepressants should be used with extreme caution in patients with evidence of cardiovascular disease because of the possibility of fluctuations in the blood pressure, arrhythmias, conduction defects, tachycardia, myocardial infarction and stroke. This also applies to patients who have family history of sudden death, cardiac dysrhythmias, or conduction disturbances. In some cases a gradual dose titration is recommended.

Tricyclic and tetracyclic antidepressants (TCAs) may cause orthostatic hypotension, reflex tachycardia, syncope, and dizziness, particularly during initiation of therapy or rapid escalation of dosage. Imipramine appears to have the greatest propensity to induce these effects, while secondary amines such as nortriptyline may do so less frequently. Tolerance to the hypotensive effects often develops after a few doses to a few weeks. Rarely, collapse and sudden death have occurred secondary to severe hypotension. Other reported adverse cardiovascular effects include tachycardia, arrhythmias, heart block, hypertension, thrombosis, thrombophlebitis, myocardial infarction, strokes, congestive heart failure, and ECG abnormalities such as PR and QT interval prolongation. Therapy with TCAs should be avoided during the acute recovery phase following myocardial infarction, and should be administered only with extreme caution in patients with hyperthyroidism, a history of cardiovascular or cerebrovascular disease, or a predisposition to hypotension. Close monitoring of cardiovascular status, including ECG changes, is recommended at all dosages. Many of the newer antidepressants, including bupropion and the selective serotonin reuptake inhibitors (SSRIs), are considerably less or minimally cardiotoxic and may be appropriate alternatives.

Tricyclic antidepressants (TCAs), can lower the seizure threshold and trigger seizures. These drugs should be used with extreme caution in patients with a history of seizures, or other predisposing factors, such as head trauma, CNS abnormalities, and alcoholism. Daily dose restrictions might apply for specific antidepressants. Physicians are encouraged to get additional dosing recommendations on the manufacturer's prescribing information.

The use of nitroimidazoles (e.g., metronidazole, tinidazole) has been associated with the development of nervous system toxicity including convulsive seizures and dose-related peripheral neuropathy, the latter characterized primarily by numbness or paresthesia of an extremity. Persistent peripheral neuropathy has been reported in some patients treated for prolonged periods. Other neurologic adverse effects include vertigo, incoordination, ataxia, confusion, agitation, hallucinations, and depression. Therapy with nitroimidazoles should be administered cautiously in patients with or predisposed to seizures or other nervous system abnormalities. Nitroimidazole therapy should be discontinued promptly if neurologic disturbances occur.

Clostridioides difficile-associated diarrhea (CDAD), formerly pseudomembranous colitis, has been reported with almost all antibacterial drugs and may range from mild diarrhea to fatal colitis. The most common culprits include clindamycin and lincomycin. Antibacterial therapy alters the normal flora of the colon, leading to overgrowth of C difficile, whose toxins A and B contribute to CDAD development. Morbidity and mortality are increased with hypertoxin-producing strains of C difficile; these infections can be resistant to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea after antibacterial use. Since CDAD has been reported to occur more than 2 months after antibacterial use, careful medical history is necessary. Therapy with broad-spectrum antibacterials and other agents with significant antibacterial activity should be administered cautiously in patients with history of gastrointestinal disease, particularly colitis; pseudomembranous colitis (generally characterized by severe, persistent diarrhea and severe abdominal cramps, and sometimes associated with the passage of blood and mucus), if it occurs, may be more severe in these patients and may be associated with flares in underlying disease activity. Antibacterial drugs not directed against C difficile may need to be stopped if CDAD is suspected or confirmed. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C difficile, and surgical evaluation should be started as clinically indicated.

Clostridioides difficile-associated diarrhea (CDAD), formerly pseudomembranous colitis, has been reported with almost all antibacterial drugs and may range from mild diarrhea to fatal colitis. The most common culprits include clindamycin and lincomycin. Antibacterial therapy alters the normal flora of the colon, leading to overgrowth of C difficile, whose toxins A and B contribute to CDAD development. Morbidity and mortality are increased with hypertoxin-producing strains of C difficile; these infections can be resistant to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea after antibacterial use. Since CDAD has been reported to occur more than 2 months after antibacterial use, careful medical history is necessary. Therapy with broad-spectrum antibacterials and other agents with significant antibacterial activity should be administered cautiously in patients with history of gastrointestinal disease, particularly colitis; pseudomembranous colitis (generally characterized by severe, persistent diarrhea and severe abdominal cramps, and sometimes associated with the passage of blood and mucus), if it occurs, may be more severe in these patients and may be associated with flares in underlying disease activity. Antibacterial drugs not directed against C difficile may need to be stopped if CDAD is suspected or confirmed. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C difficile, and surgical evaluation should be started as clinically indicated.

Tricyclic and tetracyclic antidepressants (TCAs) may cause orthostatic hypotension, reflex tachycardia, syncope, and dizziness, particularly during initiation of therapy or rapid escalation of dosage. Imipramine appears to have the greatest propensity to induce these effects, while secondary amines such as nortriptyline may do so less frequently. Tolerance to the hypotensive effects often develops after a few doses to a few weeks. Rarely, collapse and sudden death have occurred secondary to severe hypotension. Other reported adverse cardiovascular effects include tachycardia, arrhythmias, heart block, hypertension, thrombosis, thrombophlebitis, myocardial infarction, strokes, congestive heart failure, and ECG abnormalities such as PR and QT interval prolongation. Therapy with TCAs should be avoided during the acute recovery phase following myocardial infarction, and should be administered only with extreme caution in patients with hyperthyroidism, a history of cardiovascular or cerebrovascular disease, or a predisposition to hypotension. Close monitoring of cardiovascular status, including ECG changes, is recommended at all dosages. Many of the newer antidepressants, including bupropion and the selective serotonin reuptake inhibitors (SSRIs), are considerably less or minimally cardiotoxic and may be appropriate alternatives.

Tricyclic and tetracyclic antidepressants (TCAs) have anticholinergic activity, to which elderly patients are particularly sensitive. Tertiary amines such as amitriptyline and trimipramine tend to exhibit greater anticholinergic effects than other agents in the class. Therapy with TCAs should be administered cautiously in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. In patients with angle-closure glaucoma, even average doses can precipitate an attack. Glaucoma should be treated and under control prior to initiation of therapy with TCAs, and intraocular pressure monitored during therapy.

Tricyclic and tetracyclic antidepressants (TCAs) have anticholinergic activity, to which elderly patients are particularly sensitive. Tertiary amines such as amitriptyline and trimipramine tend to exhibit greater anticholinergic effects than other agents in the class. Therapy with TCAs should be administered cautiously in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. In patients with angle-closure glaucoma, even average doses can precipitate an attack. Glaucoma should be treated and under control prior to initiation of therapy with TCAs, and intraocular pressure monitored during therapy.

The use of nitroimidazoles (e.g., metronidazole, tinidazole) has rarely been associated with hematologic adverse effects such as mild, transient leukopenia, thrombocytopenia, and bone marrow aplasia. The manufacturers recommend that therapy with nitroimidazoles be administered cautiously in patients with evidence of or a history of blood dyscrasias, and that total and differential leukocyte counts be performed before and after treatment with these drugs, particularly in patients receiving repeated courses of therapy.

Tricyclic and tetracyclic antidepressants (TCAs) may cause orthostatic hypotension, reflex tachycardia, syncope, and dizziness, particularly during initiation of therapy or rapid escalation of dosage. Imipramine appears to have the greatest propensity to induce these effects, while secondary amines such as nortriptyline may do so less frequently. Tolerance to the hypotensive effects often develops after a few doses to a few weeks. Rarely, collapse and sudden death have occurred secondary to severe hypotension. Other reported adverse cardiovascular effects include tachycardia, arrhythmias, heart block, hypertension, thrombosis, thrombophlebitis, myocardial infarction, strokes, congestive heart failure, and ECG abnormalities such as PR and QT interval prolongation. Therapy with TCAs should be avoided during the acute recovery phase following myocardial infarction, and should be administered only with extreme caution in patients with hyperthyroidism, a history of cardiovascular or cerebrovascular disease, or a predisposition to hypotension. Close monitoring of cardiovascular status, including ECG changes, is recommended at all dosages. Many of the newer antidepressants, including bupropion and the selective serotonin reuptake inhibitors (SSRIs), are considerably less or minimally cardiotoxic and may be appropriate alternatives.

Tricyclic and tetracyclic antidepressants (TCAs) may cause orthostatic hypotension, reflex tachycardia, syncope, and dizziness, particularly during initiation of therapy or rapid escalation of dosage. Imipramine appears to have the greatest propensity to induce these effects, while secondary amines such as nortriptyline may do so less frequently. Tolerance to the hypotensive effects often develops after a few doses to a few weeks. Rarely, collapse and sudden death have occurred secondary to severe hypotension. Other reported adverse cardiovascular effects include tachycardia, arrhythmias, heart block, hypertension, thrombosis, thrombophlebitis, myocardial infarction, strokes, congestive heart failure, and ECG abnormalities such as PR and QT interval prolongation. Therapy with TCAs should be avoided during the acute recovery phase following myocardial infarction, and should be administered only with extreme caution in patients with hyperthyroidism, a history of cardiovascular or cerebrovascular disease, or a predisposition to hypotension. Close monitoring of cardiovascular status, including ECG changes, is recommended at all dosages. Many of the newer antidepressants, including bupropion and the selective serotonin reuptake inhibitors (SSRIs), are considerably less or minimally cardiotoxic and may be appropriate alternatives.

Tricyclic and tetracyclic antidepressants (TCAs) may cause orthostatic hypotension, reflex tachycardia, syncope, and dizziness, particularly during initiation of therapy or rapid escalation of dosage. Imipramine appears to have the greatest propensity to induce these effects, while secondary amines such as nortriptyline may do so less frequently. Tolerance to the hypotensive effects often develops after a few doses to a few weeks. Rarely, collapse and sudden death have occurred secondary to severe hypotension. Other reported adverse cardiovascular effects include tachycardia, arrhythmias, heart block, hypertension, thrombosis, thrombophlebitis, myocardial infarction, strokes, congestive heart failure, and ECG abnormalities such as PR and QT interval prolongation. Therapy with TCAs should be avoided during the acute recovery phase following myocardial infarction, and should be administered only with extreme caution in patients with hyperthyroidism, a history of cardiovascular or cerebrovascular disease, or a predisposition to hypotension. Close monitoring of cardiovascular status, including ECG changes, is recommended at all dosages. Many of the newer antidepressants, including bupropion and the selective serotonin reuptake inhibitors (SSRIs), are considerably less or minimally cardiotoxic and may be appropriate alternatives.

Tricyclic and tetracyclic antidepressants (TCAs) may cause orthostatic hypotension, reflex tachycardia, syncope, and dizziness, particularly during initiation of therapy or rapid escalation of dosage. Imipramine appears to have the greatest propensity to induce these effects, while secondary amines such as nortriptyline may do so less frequently. Tolerance to the hypotensive effects often develops after a few doses to a few weeks. Rarely, collapse and sudden death have occurred secondary to severe hypotension. Other reported adverse cardiovascular effects include tachycardia, arrhythmias, heart block, hypertension, thrombosis, thrombophlebitis, myocardial infarction, strokes, congestive heart failure, and ECG abnormalities such as PR and QT interval prolongation. Therapy with TCAs should be avoided during the acute recovery phase following myocardial infarction, and should be administered only with extreme caution in patients with hyperthyroidism, a history of cardiovascular or cerebrovascular disease, or a predisposition to hypotension. Close monitoring of cardiovascular status, including ECG changes, is recommended at all dosages. Many of the newer antidepressants, including bupropion and the selective serotonin reuptake inhibitors (SSRIs), are considerably less or minimally cardiotoxic and may be appropriate alternatives.

The use of salicylates, primarily aspirin, in children with varicella infections or influenza-like illnesses has been associated with an increased risk of Reye's syndrome. Although a causal relationship has not been established, the majority of evidence to date seems to support the association. Most authorities, including the American Academy of Pediatrics Committee on Infectious Diseases, recommend avoiding the use of salicylates in children and teenagers with known or suspected varicella or influenza and during presumed outbreaks of influenza. If antipyretic or analgesic therapy is indicated under these circumstances, acetaminophen may be an appropriate alternative. The same precautions should also be observed with related agents such as salicylamide or diflunisal because of their structural and pharmacological similarities to salicylate.

The use of most tricyclic antidepressants is contraindicated in patients that are going through the acute recovery period after a myocardial infarction.

The use of nitroimidazoles (e.g., metronidazole, tinidazole) has been associated with the development of nervous system toxicity including convulsive seizures and dose-related peripheral neuropathy, the latter characterized primarily by numbness or paresthesia of an extremity. Persistent peripheral neuropathy has been reported in some patients treated for prolonged periods. Other neurologic adverse effects include vertigo, incoordination, ataxia, confusion, agitation, hallucinations, and depression. Therapy with nitroimidazoles should be administered cautiously in patients with or predisposed to seizures or other nervous system abnormalities. Nitroimidazole therapy should be discontinued promptly if neurologic disturbances occur.

Tricyclic and tetracyclic antidepressants (TCAs) may potentiate the effects of circulating catecholamines. Enhanced sympathetic activity can provoke hypertensive crises in patients with pheochromocytoma or other tumors of the adrenal medulla, such as some neuroblastomas. Therapy with TCAs should be administered cautiously in patients with these tumors.

Tricyclic and tetracyclic antidepressants (TCAs) have anticholinergic activity, to which elderly patients are particularly sensitive. Tertiary amines such as amitriptyline and trimipramine tend to exhibit greater anticholinergic effects than other agents in the class. Therapy with TCAs should be administered cautiously in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. In patients with angle-closure glaucoma, even average doses can precipitate an attack. Glaucoma should be treated and under control prior to initiation of therapy with TCAs, and intraocular pressure monitored during therapy.

The use of salicylates, primarily aspirin, in children with varicella infections or influenza-like illnesses has been associated with an increased risk of Reye's syndrome. Although a causal relationship has not been established, the majority of evidence to date seems to support the association. Most authorities, including the American Academy of Pediatrics Committee on Infectious Diseases, recommend avoiding the use of salicylates in children and teenagers with known or suspected varicella or influenza and during presumed outbreaks of influenza. If antipyretic or analgesic therapy is indicated under these circumstances, acetaminophen may be an appropriate alternative. The same precautions should also be observed with related agents such as salicylamide or diflunisal because of their structural and pharmacological similarities to salicylate.

Nitroimidazoles (e.g., metronidazole, tinidazole, fexinidazole, secnidazole) may inhibit alcohol dehydrogenase and occasionally precipitate a disulfiram-like reaction in patients who consume alcohol while being treated. Symptoms may include abdominal cramps, nausea, vomiting, headache, flushing, rash, weakness, diarrhea, abdominal pain, dizziness, sweating, and hypotension. Patients should be instructed to avoid alcohol-containing products during nitroimidazole therapy and for at least 48 hours (fexinidazole, secnidazole) to 72 hours (metronidazole, tinidazole) after the last dose. Therapy with nitroimidazoles should be administered cautiously in patients who might be prone to acute alcohol intake. An alternative therapy may be appropriate.

Tricyclic antidepressants can enhance the response to alcohol. In patients who may use alcohol excessively, it should be borne in mind that the potentiation may increase the danger inherent in any suicide attempt or overdosage.

Tricyclic antidepressants (TCAs) may aggravate symptoms of psychosis in schizophrenic patients, particularly those with paranoid symptomatology. Depressed patients, usually those with bipolar disorder, may experience a switch from depression to mania or hypomania. These occurrences have also been reported rarely with the tetracyclic antidepressant, maprotiline. Therapy with these agents should be administered cautiously in patients with schizophrenia, bipolar disorder, or a history of mania.

A major depressive episode can be the initial presentation of bipolar disorder. Patients with depressive symptoms should be adequately screened to determine if they are at risk for bipolar disorder prior to initiating treatment with a tricyclic antidepressant. This screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression. It should be noted that tricyclic antidepressants are not approved for use in treating bipolar depression.

All salicylates can interfere with the action of vitamin K and induce a dose-dependent alteration in hepatic synthesis of coagulation factors VII, IX and X. At usual recommended dosages, a slight increase in prothrombin time (PT) may occur. Therapy with salicylates, especially if given in high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The same precaution should also be observed with the use of related agents such as salicylamide because of their structural and pharmacological similarities to salicylate.

The use of tricyclic and tetracyclic antidepressants (TCAs) has rarely been associated with bone marrow suppression. Leukopenia, agranulocytosis, thrombocytopenia, anemia, eosinophilia, purpura, and pancytopenia have been reported with some TCAs. Patients with preexisting bone marrow suppression or blood dyscrasias receiving TCAs should be monitored closely during therapy for further decreases in blood counts.

All salicylates can interfere with the action of vitamin K and induce a dose-dependent alteration in hepatic synthesis of coagulation factors VII, IX and X. At usual recommended dosages, a slight increase in prothrombin time (PT) may occur. Therapy with salicylates, especially if given in high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The same precaution should also be observed with the use of related agents such as salicylamide because of their structural and pharmacological similarities to salicylate.

Flagyl I.V. RTU (brand of metronidazole ready-to-use injection) contains 14 mEq of sodium per each 500 mg dose of metronidazole. The sodium content should be considered when this product is used in patients with conditions that may require sodium restriction, such as congestive heart failure, hypertension, and fluid retention.

Both elevation and lowering of blood sugar levels have been reported with the use of some tricyclic antidepressants (TCAs). Rarely, these effects have also occurred with maprotiline, a tetracyclic antidepressant. Patients with diabetes should be monitored for worsening control of blood glucose when treated with these agents, particularly during dosage escalation or whenever dosage has been altered.

There have been reports of both elevation and lowering of blood sugar levels in patients receiving tricyclic antidepressants. These drugs should be used with caution in patients with hypoglycemia, hyperglycemia or diabetes. Monitoring sugar levels is recommended.

The use of oral tetracycline capsules and tablets has been associated with esophageal irritation and ulceration in patients who ingested the drug without sufficient fluid shortly before bedtime. Therapy with solid formulations of tetracyclines should preferably be avoided in patients with esophageal obstruction, compression or dyskinesia. If the drugs are used, patients should be advised not to take the medication just before retiring and to drink fluids liberally.

Flagyl I.V. RTU (brand of metronidazole ready-to-use injection) contains 14 mEq of sodium per each 500 mg dose of metronidazole. The sodium content should be considered when this product is used in patients with conditions that may require sodium restriction, such as congestive heart failure, hypertension, and fluid retention.

Tricyclic antidepressants as other type of antidepressants have an effect on pupil size causing dilation. This effect can potentially narrow the eye angle resulting in increased intraocular pressure and angle closure glaucoma, especially in predisposed patients. These drugs should be used with caution in patients with anatomically narrow angle or history of glaucoma. Doxepin hydrochloride capsules are contraindicated in patients with glaucoma.

Metronidazole and its metabolites are moderately removed by hemodialysis. Doses should either be scheduled for administration after dialysis or supplemental doses be given after dialysis.

Flagyl I.V. RTU (brand of metronidazole ready-to-use injection) contains 14 mEq of sodium per each 500 mg dose of metronidazole. The sodium content should be considered when this product is used in patients with conditions that may require sodium restriction, such as congestive heart failure, hypertension, and fluid retention.

Flagyl I.V. RTU (brand of metronidazole ready-to-use injection) contains 14 mEq of sodium per each 500 mg dose of metronidazole. The sodium content should be considered when this product is used in patients with conditions that may require sodium restriction, such as congestive heart failure, hypertension, and fluid retention.

Most tricyclic antidepressants should be administered with caution in hyperthyroid patients or those receiving thyroid medication as they may develop arrhythmias when these drugs are given.

There have been reports of both elevation and lowering of blood sugar levels in patients receiving tricyclic antidepressants. These drugs should be used with caution in patients with hypoglycemia, hyperglycemia or diabetes. Monitoring sugar levels is recommended.

In general, tricyclic antidepressants should be used with caution in patients with liver or renal disease, as these drugs are metabolized and excreted through the liver and kidneys. Dose selection, especially in the elderly patients that might have liver or renal dysfunction, should usually be limited to the smallest effective total daily dose. Some tricyclic antidepressants such as clomipramine and nortriptyline have occasionally been associated with elevations in SGOT (AST) and SGPT (ALT), and other hepatic adverse events such as jaundice. Although serious liver injury has only been reported rarely, therapy with these drugs should be administered cautiously in patients with preexisting liver disease and periodic monitoring of liver enzyme levels is recommended.

Tricyclic and tetracyclic antidepressants (TCAs) are known to undergo metabolism in the liver. Some of the metabolites, such as those of imipramine, clomipramine and desipramine, may be pharmacologically active. Many of the metabolites are also excreted by the kidney. There are very limited data concerning the use of TCAs in patients with renal and/or liver disease. Therapy with TCAs should be administered cautiously in patients with significantly impaired renal or hepatic function. Dosage adjustments may be necessary.

Metronidazole is extensively metabolized by the liver to both pharmacologically active and inactive compounds. The plasma clearance of metronidazole may be decreased and the half-life prolonged in patients with impaired hepatic function. Therapy with metronidazole should be administered cautiously at reduced dosages in patients with severe liver disease.

The use of tetracyclines has rarely been associated with hepatotoxicity. Histologic fatty changes of the liver, elevated liver enzymes, and jaundice have been reported, primarily in patients treated with large doses of intravenous tetracycline hydrochloride (no longer available in the U.S.) but also in patients receiving high oral doses of these drugs. Therapy with tetracyclines should be administered cautiously in patients with preexisting liver disease or biliary obstruction. Reduced dosages may be appropriate, particularly with minocycline and doxycycline, since the former is metabolized by the liver and the latter undergoes enterohepatic recycling. Liver function tests are recommended prior to and during therapy, and the concomitant use of other potentially hepatotoxic drugs should be avoided.

Tricyclic antidepressants (TCAs) may aggravate symptoms of psychosis in schizophrenic patients, particularly those with paranoid symptomatology. Depressed patients, usually those with bipolar disorder, may experience a switch from depression to mania or hypomania. These occurrences have also been reported rarely with the tetracyclic antidepressant, maprotiline. Therapy with these agents should be administered cautiously in patients with schizophrenia, bipolar disorder, or a history of mania.

The use of some tricyclic antidepressants has been associated with neutropenia (ANC < 500/mm3) and agranulocytosis (ANC < 500/mm3). Leukocyte and differential blood counts should be performed in patients that develop fever and sore throat during treatment. Therapy should be discontinued if there is evidence of pathologic neutrophil depression.

Tetracyclines (except doxycycline) are eliminated by the kidney to various extent. Patients with renal impairment may be at greater risk for tetracycline-associated hepatic and/or renal toxicity (increased BUN with consequent azotemia, hyperphosphatemia, and acidosis) due to decreased drug clearance. Therapy with tetracyclines should be administered cautiously at reduced dosages in patients with renal impairment. Clinical monitoring of renal and liver function is recommended, and serum tetracycline levels may be necessary during prolonged therapy.

In general, tricyclic antidepressants should be used with caution in patients with liver or renal disease, as these drugs are metabolized and excreted through the liver and kidneys. Dose selection, especially in the elderly patients that might have liver or renal dysfunction, should usually be limited to the smallest effective total daily dose. Some tricyclic antidepressants such as clomipramine and nortriptyline have occasionally been associated with elevations in SGOT (AST) and SGPT (ALT), and other hepatic adverse events such as jaundice. Although serious liver injury has only been reported rarely, therapy with these drugs should be administered cautiously in patients with preexisting liver disease and periodic monitoring of liver enzyme levels is recommended.

Tricyclic and tetracyclic antidepressants (TCAs) are known to undergo metabolism in the liver. Some of the metabolites, such as those of imipramine, clomipramine and desipramine, may be pharmacologically active. Many of the metabolites are also excreted by the kidney. There are very limited data concerning the use of TCAs in patients with renal and/or liver disease. Therapy with TCAs should be administered cautiously in patients with significantly impaired renal or hepatic function. Dosage adjustments may be necessary.

Some tricyclic antidepressants have shown to cause activation or exacerbation of psychosis in schizophrenic patients. A dosage reduction might be required.

Tricyclic antidepressants (TCAs) may aggravate symptoms of psychosis in schizophrenic patients, particularly those with paranoid symptomatology. Depressed patients, usually those with bipolar disorder, may experience a switch from depression to mania or hypomania. These occurrences have also been reported rarely with the tetracyclic antidepressant, maprotiline. Therapy with these agents should be administered cautiously in patients with schizophrenia, bipolar disorder, or a history of mania.

Tricyclic and tetracyclic antidepressants (TCAs) have anticholinergic activity, to which elderly patients are particularly sensitive. Tertiary amines such as amitriptyline and trimipramine tend to exhibit greater anticholinergic effects than other agents in the class. As with other drugs that possess anticholinergic activity, TCAs may aggravate tardive dyskinesia or induce previously suppressed symptoms. Patients with tardive dyskinesia requiring therapy with TCAs should be monitored for exacerbation of the condition.

All salicylates can interfere with the action of vitamin K and induce a dose-dependent alteration in hepatic synthesis of coagulation factors VII, IX and X. At usual recommended dosages, a slight increase in prothrombin time (PT) may occur. Therapy with salicylates, especially if given in high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The same precaution should also be observed with the use of related agents such as salicylamide because of their structural and pharmacological similarities to salicylate.

All salicylates can interfere with the action of vitamin K and induce a dose-dependent alteration in hepatic synthesis of coagulation factors VII, IX and X. At usual recommended dosages, a slight increase in prothrombin time (PT) may occur. Therapy with salicylates, especially if given in high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The same precaution should also be observed with the use of related agents such as salicylamide because of their structural and pharmacological similarities to salicylate.

Due to their anticholinergic properties, tricyclic antidepressants should be administered with caution in patients with history of urinary retention. Particularly doxepin hydrochloride capsules are contraindicated in patients with tendency to urinary retention.

All salicylates can interfere with the action of vitamin K and induce a dose-dependent alteration in hepatic synthesis of coagulation factors VII, IX and X. At usual recommended dosages, a slight increase in prothrombin time (PT) may occur. Therapy with salicylates, especially if given in high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The same precaution should also be observed with the use of related agents such as salicylamide because of their structural and pharmacological similarities to salicylate.