Drug Interactions between dezocine and hydroxyzine

Do not use alcohol or medications that contain alcohol while you are receiving treatment with dezocine. This may increase nervous system side effects such as drowsiness, dizziness, lightheadedness, difficulty concentrating, and impairment in thinking and judgment. In severe cases, low blood pressure, respiratory distress, fainting, coma, or even death may occur. If you are taking an extended-release formulation, the pill should be swallowed whole (i.E., do not crush, chew, or divide the pill). Do not use more than the recommended dose of dezocine, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medication without first talking to your doctor.

Alcohol can increase the nervous system side effects of hydrOXYzine such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with hydrOXYzine. Do not use more than the recommended dose of hydrOXYzine, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

Opioid partial agonists may produce respiratory depression by decreasing respiratory drive and increasing airway resistance. A "ceiling effect" has been noted for these agents and increasing doses do not produce proportional or further respiratory depression. However, the duration of effect is prolonged. At therapeutic analgesic dosages, the respiratory effects are usually not clinically important except in patients with preexisting pulmonary impairment. Therapy with opioid partial agonists should be avoided or administered with extreme caution and initiated at reduced dosages in patients with severe CNS or respiratory depression; acute alcohol intoxication; sleep apnea; hypoxia, anoxia, or hypercapnia; upper airway obstruction; chronic pulmonary insufficiency; a limited ventilatory reserve; or other respiratory disorders. In the presence of excessive respiratory secretions, the use of opioid partial agonists may also be problematic because they decrease ciliary activity and reduce the cough reflex. Caution is also advised in patients who may be at increased risk for respiratory depression, such as comatose patients or those with head injury, intracranial lesions, or intracranial hypertension. Clinical monitoring of pulmonary function is recommended, and equipment for resuscitation should be immediately available if parenteral routes are used. Naloxone may be administered to reverse clinically significant respiratory depression.

Opioid partial agonists have the potential to cause dependence and abuse, particularly in patients with a history of drug abuse. Tolerance as well as physical and psychological dependence can develop after prolonged use, and abrupt cessation or a significant reduction in dosage may precipitate withdrawal symptoms. Because of their opioid antagonistic effect, withdrawal symptoms may also occur if opioid partial agonists are administered to patients with an opioid dependence or in whom substantial amounts of narcotics have recently been administered. Therapy with opioid partial agonists is not recommended in patients who are physically dependent on narcotics. Addiction-prone individuals, such as those with a history of alcohol or substance abuse, should be under careful surveillance or medical supervision when treated with opioid partial agonists. It may be prudent to refrain from dispensing large quantities of medication to these patients. After prolonged use or if dependency is suspected, withdrawal of opioid therapy should be undertaken gradually using a dosage-tapering schedule.

Opioid partial agonists may produce respiratory depression by decreasing respiratory drive and increasing airway resistance. A "ceiling effect" has been noted for these agents and increasing doses do not produce proportional or further respiratory depression. However, the duration of effect is prolonged. At therapeutic analgesic dosages, the respiratory effects are usually not clinically important except in patients with preexisting pulmonary impairment. Therapy with opioid partial agonists should be avoided or administered with extreme caution and initiated at reduced dosages in patients with severe CNS or respiratory depression; acute alcohol intoxication; sleep apnea; hypoxia, anoxia, or hypercapnia; upper airway obstruction; chronic pulmonary insufficiency; a limited ventilatory reserve; or other respiratory disorders. In the presence of excessive respiratory secretions, the use of opioid partial agonists may also be problematic because they decrease ciliary activity and reduce the cough reflex. Caution is also advised in patients who may be at increased risk for respiratory depression, such as comatose patients or those with head injury, intracranial lesions, or intracranial hypertension. Clinical monitoring of pulmonary function is recommended, and equipment for resuscitation should be immediately available if parenteral routes are used. Naloxone may be administered to reverse clinically significant respiratory depression.

Opioid partial agonists may produce respiratory depression by decreasing respiratory drive and increasing airway resistance. A "ceiling effect" has been noted for these agents and increasing doses do not produce proportional or further respiratory depression. However, the duration of effect is prolonged. At therapeutic analgesic dosages, the respiratory effects are usually not clinically important except in patients with preexisting pulmonary impairment. Therapy with opioid partial agonists should be avoided or administered with extreme caution and initiated at reduced dosages in patients with severe CNS or respiratory depression; acute alcohol intoxication; sleep apnea; hypoxia, anoxia, or hypercapnia; upper airway obstruction; chronic pulmonary insufficiency; a limited ventilatory reserve; or other respiratory disorders. In the presence of excessive respiratory secretions, the use of opioid partial agonists may also be problematic because they decrease ciliary activity and reduce the cough reflex. Caution is also advised in patients who may be at increased risk for respiratory depression, such as comatose patients or those with head injury, intracranial lesions, or intracranial hypertension. Clinical monitoring of pulmonary function is recommended, and equipment for resuscitation should be immediately available if parenteral routes are used. Naloxone may be administered to reverse clinically significant respiratory depression.

Opioid partial agonists may produce respiratory depression by decreasing respiratory drive and increasing airway resistance. A "ceiling effect" has been noted for these agents and increasing doses do not produce proportional or further respiratory depression. However, the duration of effect is prolonged. At therapeutic analgesic dosages, the respiratory effects are usually not clinically important except in patients with preexisting pulmonary impairment. Therapy with opioid partial agonists should be avoided or administered with extreme caution and initiated at reduced dosages in patients with severe CNS or respiratory depression; acute alcohol intoxication; sleep apnea; hypoxia, anoxia, or hypercapnia; upper airway obstruction; chronic pulmonary insufficiency; a limited ventilatory reserve; or other respiratory disorders. In the presence of excessive respiratory secretions, the use of opioid partial agonists may also be problematic because they decrease ciliary activity and reduce the cough reflex. Caution is also advised in patients who may be at increased risk for respiratory depression, such as comatose patients or those with head injury, intracranial lesions, or intracranial hypertension. Clinical monitoring of pulmonary function is recommended, and equipment for resuscitation should be immediately available if parenteral routes are used. Naloxone may be administered to reverse clinically significant respiratory depression.

The hypoventilation associated with administration of opioid partial agonists can induce cerebral hypoxia and vasodilatation with resultant increase in intracranial pressure. Unless mechanical ventilation is provided, extreme caution is advised when opioid partial agonists are given to patients with head injury, intracranial lesions, or a preexisting elevated CSF pressure. Also, clinicians treating such patients should be aware that opioid partial agonists may interfere with the evaluation of CNS function, especially with respect to consciousness levels, respiratory status, and pupillary changes.

The hypoventilation associated with administration of opioid partial agonists can induce cerebral hypoxia and vasodilatation with resultant increase in intracranial pressure. Unless mechanical ventilation is provided, extreme caution is advised when opioid partial agonists are given to patients with head injury, intracranial lesions, or a preexisting elevated CSF pressure. Also, clinicians treating such patients should be aware that opioid partial agonists may interfere with the evaluation of CNS function, especially with respect to consciousness levels, respiratory status, and pupillary changes.

Opioid partial agonists may produce respiratory depression by decreasing respiratory drive and increasing airway resistance. A "ceiling effect" has been noted for these agents and increasing doses do not produce proportional or further respiratory depression. However, the duration of effect is prolonged. At therapeutic analgesic dosages, the respiratory effects are usually not clinically important except in patients with preexisting pulmonary impairment. Therapy with opioid partial agonists should be avoided or administered with extreme caution and initiated at reduced dosages in patients with severe CNS or respiratory depression; acute alcohol intoxication; sleep apnea; hypoxia, anoxia, or hypercapnia; upper airway obstruction; chronic pulmonary insufficiency; a limited ventilatory reserve; or other respiratory disorders. In the presence of excessive respiratory secretions, the use of opioid partial agonists may also be problematic because they decrease ciliary activity and reduce the cough reflex. Caution is also advised in patients who may be at increased risk for respiratory depression, such as comatose patients or those with head injury, intracranial lesions, or intracranial hypertension. Clinical monitoring of pulmonary function is recommended, and equipment for resuscitation should be immediately available if parenteral routes are used. Naloxone may be administered to reverse clinically significant respiratory depression.

Narcotic (opioid) analgesic agents increase smooth muscle tone in the gastrointestinal tract and decrease peristalsis, which can lead to elevated intraluminal pressure, spasm, and constipation following prolonged use. In patients with severe or acute inflammatory bowel disease, the decrease in colonic motility may induce toxic megacolon. Therapy with opioids should be administered cautiously in patients with gastrointestinal obstruction, constipation, inflammatory bowel disease, or recent gastrointestinal tract surgery. Gastrointestinal effects appear to be the most pronounced with morphine.

A variety of abnormal thinking and behavior changes have been reported to occur in association with the use of most anxiolytics, sedatives and hypnotics. Some of these changes include decreased inhibition, aggressiveness, agitation, and hallucinations. These drugs can cause or exacerbate mental depression and cause suicidal behavior and ideation. Therapy with these drugs should be administered cautiously in patients with a history of depression or other psychiatric disorders. Patients should be monitored for any changes in mood or behavior. It may be prudent to refrain from dispensing large quantities of medication to these patients.

Opioid partial agonists have the potential to cause dependence and abuse, particularly in patients with a history of drug abuse. Tolerance as well as physical and psychological dependence can develop after prolonged use, and abrupt cessation or a significant reduction in dosage may precipitate withdrawal symptoms. Because of their opioid antagonistic effect, withdrawal symptoms may also occur if opioid partial agonists are administered to patients with an opioid dependence or in whom substantial amounts of narcotics have recently been administered. Therapy with opioid partial agonists is not recommended in patients who are physically dependent on narcotics. Addiction-prone individuals, such as those with a history of alcohol or substance abuse, should be under careful surveillance or medical supervision when treated with opioid partial agonists. It may be prudent to refrain from dispensing large quantities of medication to these patients. After prolonged use or if dependency is suspected, withdrawal of opioid therapy should be undertaken gradually using a dosage-tapering schedule.

Opioid analgesics are contraindicated in patients with known or suspected gastrointestinal obstruction, including paralytic ileus.

Narcotic (opioid) analgesic agents increase smooth muscle tone in the gastrointestinal tract and decrease peristalsis, which can lead to elevated intraluminal pressure, spasm, and constipation following prolonged use. In patients with severe or acute inflammatory bowel disease, the decrease in colonic motility may induce toxic megacolon. Therapy with opioids should be administered cautiously in patients with gastrointestinal obstruction, constipation, inflammatory bowel disease, or recent gastrointestinal tract surgery. Gastrointestinal effects appear to be the most pronounced with morphine.

Opioid partial agonists may produce respiratory depression by decreasing respiratory drive and increasing airway resistance. A "ceiling effect" has been noted for these agents and increasing doses do not produce proportional or further respiratory depression. However, the duration of effect is prolonged. At therapeutic analgesic dosages, the respiratory effects are usually not clinically important except in patients with preexisting pulmonary impairment. Therapy with opioid partial agonists should be avoided or administered with extreme caution and initiated at reduced dosages in patients with severe CNS or respiratory depression; acute alcohol intoxication; sleep apnea; hypoxia, anoxia, or hypercapnia; upper airway obstruction; chronic pulmonary insufficiency; a limited ventilatory reserve; or other respiratory disorders. In the presence of excessive respiratory secretions, the use of opioid partial agonists may also be problematic because they decrease ciliary activity and reduce the cough reflex. Caution is also advised in patients who may be at increased risk for respiratory depression, such as comatose patients or those with head injury, intracranial lesions, or intracranial hypertension. Clinical monitoring of pulmonary function is recommended, and equipment for resuscitation should be immediately available if parenteral routes are used. Naloxone may be administered to reverse clinically significant respiratory depression.

The hypoventilation associated with administration of opioid partial agonists can induce cerebral hypoxia and vasodilatation with resultant increase in intracranial pressure. Unless mechanical ventilation is provided, extreme caution is advised when opioid partial agonists are given to patients with head injury, intracranial lesions, or a preexisting elevated CSF pressure. Also, clinicians treating such patients should be aware that opioid partial agonists may interfere with the evaluation of CNS function, especially with respect to consciousness levels, respiratory status, and pupillary changes.

Hydroxyzine is contraindicated in patients with a QT prolonged interval. Cases of QT prolongation and Torsade de Pointes have been reported during postmarketing studies. Most of the cases reported occurred in patients with other risk factors for QT prolongation, such as preexisting heart disease, electrolyte imbalances or arrhythmogenic drug use. Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, family history of long QT syndrome or other predisposing conditions, as well as myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

Narcotic (opioid) analgesic agents may prolong and/or worsen diarrhea associated with organisms that invade the intestinal mucosa, such as toxigenic Escherichia coli, Salmonella, Shigella, and pseudomembranous colitis due to broad-spectrum antibiotics. These agents decrease gastrointestinal motility, which may delay the excretion of infective gastroenteric organisms and/or their toxins. Other symptoms and complications such as fever, shedding of organisms, and extraintestinal illness may also be increased or prolonged. Therapy with opioids should be avoided or administered cautiously in patients with infectious diarrhea, particularly that due to pseudomembranous enterocolitis or enterotoxin-producing bacteria or if accompanied by high fever, pus, or blood in the stool.

Narcotic (opioid) analgesic agents increase smooth muscle tone in the gastrointestinal tract and decrease peristalsis, which can lead to elevated intraluminal pressure, spasm, and constipation following prolonged use. In patients with severe or acute inflammatory bowel disease, the decrease in colonic motility may induce toxic megacolon. Therapy with opioids should be administered cautiously in patients with gastrointestinal obstruction, constipation, inflammatory bowel disease, or recent gastrointestinal tract surgery. Gastrointestinal effects appear to be the most pronounced with morphine.

Narcotic (opioid) analgesic agents increase smooth muscle tone in the gastrointestinal tract and decrease peristalsis, which can lead to elevated intraluminal pressure, spasm, and constipation following prolonged use. In patients with severe or acute inflammatory bowel disease, the decrease in colonic motility may induce toxic megacolon. Therapy with opioids should be administered cautiously in patients with gastrointestinal obstruction, constipation, inflammatory bowel disease, or recent gastrointestinal tract surgery. Gastrointestinal effects appear to be the most pronounced with morphine.

Opioid partial agonists may increase systemic and pulmonary arterial pressure and systemic vascular resistance, particularly when given by IV administration. Data are available for pentazocine and butorphanol. Therapy with opioid partial agonists should be administered cautiously and only if the benefit justifies the risk in patients with acute myocardial infarction (especially if accompanied by hypertension or left ventricular failure) or coronary insufficiency.

Hydroxyzine is contraindicated in patients with a QT prolonged interval. Cases of QT prolongation and Torsade de Pointes have been reported during postmarketing studies. Most of the cases reported occurred in patients with other risk factors for QT prolongation, such as preexisting heart disease, electrolyte imbalances or arrhythmogenic drug use. Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, family history of long QT syndrome or other predisposing conditions, as well as myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

Hydroxyzine is contraindicated in patients with a QT prolonged interval. Cases of QT prolongation and Torsade de Pointes have been reported during postmarketing studies. Most of the cases reported occurred in patients with other risk factors for QT prolongation, such as preexisting heart disease, electrolyte imbalances or arrhythmogenic drug use. Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, family history of long QT syndrome or other predisposing conditions, as well as myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

The use of narcotic (opioid) analgesic agents is contraindicated in premature infants. These agents may cross the immature blood-brain barrier to a greater extent than in adults, resulting in disproportionate respiratory depression.

Opioid partial agonists may produce respiratory depression by decreasing respiratory drive and increasing airway resistance. A "ceiling effect" has been noted for these agents and increasing doses do not produce proportional or further respiratory depression. However, the duration of effect is prolonged. At therapeutic analgesic dosages, the respiratory effects are usually not clinically important except in patients with preexisting pulmonary impairment. Therapy with opioid partial agonists should be avoided or administered with extreme caution and initiated at reduced dosages in patients with severe CNS or respiratory depression; acute alcohol intoxication; sleep apnea; hypoxia, anoxia, or hypercapnia; upper airway obstruction; chronic pulmonary insufficiency; a limited ventilatory reserve; or other respiratory disorders. In the presence of excessive respiratory secretions, the use of opioid partial agonists may also be problematic because they decrease ciliary activity and reduce the cough reflex. Caution is also advised in patients who may be at increased risk for respiratory depression, such as comatose patients or those with head injury, intracranial lesions, or intracranial hypertension. Clinical monitoring of pulmonary function is recommended, and equipment for resuscitation should be immediately available if parenteral routes are used. Naloxone may be administered to reverse clinically significant respiratory depression.

Opioid partial agonists may produce respiratory depression by decreasing respiratory drive and increasing airway resistance. A "ceiling effect" has been noted for these agents and increasing doses do not produce proportional or further respiratory depression. However, the duration of effect is prolonged. At therapeutic analgesic dosages, the respiratory effects are usually not clinically important except in patients with preexisting pulmonary impairment. Therapy with opioid partial agonists should be avoided or administered with extreme caution and initiated at reduced dosages in patients with severe CNS or respiratory depression; acute alcohol intoxication; sleep apnea; hypoxia, anoxia, or hypercapnia; upper airway obstruction; chronic pulmonary insufficiency; a limited ventilatory reserve; or other respiratory disorders. In the presence of excessive respiratory secretions, the use of opioid partial agonists may also be problematic because they decrease ciliary activity and reduce the cough reflex. Caution is also advised in patients who may be at increased risk for respiratory depression, such as comatose patients or those with head injury, intracranial lesions, or intracranial hypertension. Clinical monitoring of pulmonary function is recommended, and equipment for resuscitation should be immediately available if parenteral routes are used. Naloxone may be administered to reverse clinically significant respiratory depression.

Hydroxyzine is contraindicated in patients with a QT prolonged interval. Cases of QT prolongation and Torsade de Pointes have been reported during postmarketing studies. Most of the cases reported occurred in patients with other risk factors for QT prolongation, such as preexisting heart disease, electrolyte imbalances or arrhythmogenic drug use. Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, family history of long QT syndrome or other predisposing conditions, as well as myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

Patients with Addison's disease may have increased risk of respiratory depression and prolonged CNS depression associated with the use of narcotic (opioid) analgesic agents. Conversely, these agents may cause or potentiate adrenal insufficiency. Therapy with opioids should be administered cautiously and initiated at reduced dosages in patients with adrenocortical insufficiency. Subsequent doses should be titrated based on individual response rather than a fixed dosing schedule.

It has been suggested that the anticholinergic effect of antihistamines may reduce the volume and cause thickening of bronchial secretions, resulting in obstruction of respiratory tract. Some manufacturers and clinicians recommend that therapy with antihistamines be administered cautiously in patients with asthma or chronic obstructive pulmonary disease.

Opioid agonists may cause spasm of the sphincter of Oddi, which may increase biliary tract pressure. Other opioid-induced effects may include a reduction in biliary and pancreatic secretions and transient elevations in serum amylase. Patients with biliary tract disease (including acute pancreatitis) should be regularly evaluated for worsening symptoms. Therapy with opioids should be administered cautiously in patients with biliary tract disease, gallbladder disease, or acute pancreatitis.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

It has been suggested that the anticholinergic effect of antihistamines may reduce the volume and cause thickening of bronchial secretions, resulting in obstruction of respiratory tract. Some manufacturers and clinicians recommend that therapy with antihistamines be administered cautiously in patients with asthma or chronic obstructive pulmonary disease.

Opioid agonists may cause spasm of the sphincter of Oddi, which may increase biliary tract pressure. Other opioid-induced effects may include a reduction in biliary and pancreatic secretions and transient elevations in serum amylase. Patients with biliary tract disease (including acute pancreatitis) should be regularly evaluated for worsening symptoms. Therapy with opioids should be administered cautiously in patients with biliary tract disease, gallbladder disease, or acute pancreatitis.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, 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. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, 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. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

Some hypnotic drugs can have an anticholinergic effect and should be used with caution in patients with glaucoma, and trouble urinating due to retention or enlarged prostate.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

Limited pharmacokinetic data are available for the older, first-generation antihistamines. Many appear to be primarily metabolized by the liver, and both parent drugs and metabolites are excreted in the urine. Patients with renal and/or liver disease may be at greater risk for adverse effects from antihistamines due to drug and metabolite accumulation. Therapy with antihistamines should be administered cautiously in such patients. Lower initial dosages may be appropriate.

Some anxiolytics, sedatives and hypnotics are extensively metabolized by the liver, and excreted in the urine. Patients with impaired renal and/or hepatic function may be at greater risk for adverse effects, including central nervous system and respiratory depression, due to drug and metabolite accumulation. Therapy with these drugs should be administered cautiously in such patients, with careful dose selection usually starting at the low end of the dosing range.

In general, anxiolytics, sedatives and hypnotics are extensively metabolized by the liver. Their plasma clearance may be decreased and their half-life prolonged in patients with impaired hepatic function. Therapy with these drugs should be administered cautiously in patients with liver disease (some are not recommended in severe liver impairment), and the dosage should be adjusted accordingly. Laboratory testing is recommended prior and during treatment.

Narcotic (opioid) analgesic agents are extensively metabolized by the liver, and several of them (e.g., codeine, hydrocodone, meperidine, methadone, morphine, propoxyphene) have active metabolites that are further converted to inactive substances. The serum concentrations of these agents and their metabolites may be increased and the half-lives prolonged in patients with impaired hepatic function. Therapy with opioids should be administered cautiously and initiated at reduced dosages in patients with liver disease. Subsequent doses should be titrated based on individual response rather than a fixed dosing schedule.

Opioid agonists may cause spasm of the sphincter of Oddi, which may increase biliary tract pressure. Other opioid-induced effects may include a reduction in biliary and pancreatic secretions and transient elevations in serum amylase. Patients with biliary tract disease (including acute pancreatitis) should be regularly evaluated for worsening symptoms. Therapy with opioids should be administered cautiously in patients with biliary tract disease, gallbladder disease, or acute pancreatitis.

Limited pharmacokinetic data are available for the older, first-generation antihistamines. Many appear to be primarily metabolized by the liver, and both parent drugs and metabolites are excreted in the urine. Patients with renal and/or liver disease may be at greater risk for adverse effects from antihistamines due to drug and metabolite accumulation. Therapy with antihistamines should be administered cautiously in such patients. Lower initial dosages may be appropriate.

Although narcotic (opioid) analgesic agents are generally metabolized by the liver, renal impairment can alter the elimination of these agents and their metabolites (some of which are pharmacologically active), resulting in drug accumulation and increased risk of toxicity. Therapy with opioids should be administered cautiously and initiated at reduced dosages in patients with significantly impaired renal function. Subsequent doses should be titrated based on individual response rather than a fixed dosing schedule.

Some anxiolytics, sedatives and hypnotics are extensively metabolized by the liver, and excreted in the urine. Patients with impaired renal and/or hepatic function may be at greater risk for adverse effects, including central nervous system and respiratory depression, due to drug and metabolite accumulation. Therapy with these drugs should be administered cautiously in such patients, with careful dose selection usually starting at the low end of the dosing range.

Narcotic (opioid) analgesic agents may increase the frequency of seizures in patients with seizure disorders, may increase the risk of seizures occurring in other clinical settings associated with seizures, and, at higher dosages, have been reported to induce seizures in patients without history of seizures. Patients with history of seizure disorders should be regularly evaluated for worsened seizure control during therapy. Prolonged meperidine use may increase the risk of toxicity (e.g., seizures) from the accumulation of the active metabolite (normeperidine).

Narcotic (opioid) analgesic agents may inhibit the urinary voiding reflex and increase the tone of the vesical sphincter in the bladder. Acute urinary retention requiring catheterization may occur, particularly in patients with prostatic hypertrophy or urethral stricture and in older adult patients. These agents may also decrease urine production via direct effects on the kidney and central stimulation of the release of vasopressin. Therapy with opioids should be administered cautiously in patients with or predisposed to urinary retention and/or oliguria. The effects on smooth muscle tone appear to be the most pronounced with morphine.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, 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. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

Some hypnotic drugs can have an anticholinergic effect and should be used with caution in patients with glaucoma, and trouble urinating due to retention or enlarged prostate.