Drug Interactions between hydroxyzine and ofloxacin

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.

In general, multivitamin with minerals and ofloxacin should not be taken orally at the same time. Products that contain aluminum, calcium, iron, magnesium, zinc and/or other minerals may interfere with the absorption of ofloxacin into the bloodstream and reduce its effectiveness in treating your infection. If possible, it may be best to avoid taking multivitamin with minerals while you are being treated with ofloxacin. Otherwise, you should separate their dosing times by as much as possible, usually at least 2 to 4 hours. Talk to your healthcare provider if you are unsure whether your medications contain something that could potentially interact or if you have questions on how to take this or other medications you are prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Quinolones have been reported to prolong the QT interval of the electrocardiogram in some patients. QT prolongation may potentiate the risk of ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes. The risk appears to be greatest with grepafloxacin and sparfloxacin (both are no longer marketed in the U.S.), although cardiovascular morbidity and mortality attributable to QT prolongation have also been reported rarely with others like gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Reported cases have primarily occurred in patients with advanced age, cardiac disease, electrolyte disturbances, and/or underlying medical problems for which they were receiving concomitant medications known to prolong the QT interval. Therapy with quinolones should be avoided in patients with known QT prolongation and/or uncorrected electrolyte disorders (hypokalemia or hypomagnesemia) and in patients treated concomitantly with class IA or III antiarrhythmic agents. Cautious use with ECG monitoring is advised in patients with other proarrhythmic conditions such as clinically significant bradycardia, congestive heart failure, acute myocardial ischemia, and atrial fibrillation. As QT prolongation may be a concentration-dependent effect, it is important that the recommended dosages or infusion rates of these drugs not be exceeded, particularly in patients with renal and/or hepatic impairment.

Quinolones have been reported to prolong the QT interval of the electrocardiogram in some patients. QT prolongation may potentiate the risk of ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes. The risk appears to be greatest with grepafloxacin and sparfloxacin (both are no longer marketed in the U.S.), although cardiovascular morbidity and mortality attributable to QT prolongation have also been reported rarely with others like gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Reported cases have primarily occurred in patients with advanced age, cardiac disease, electrolyte disturbances, and/or underlying medical problems for which they were receiving concomitant medications known to prolong the QT interval. Therapy with quinolones should be avoided in patients with known QT prolongation and/or uncorrected electrolyte disorders (hypokalemia or hypomagnesemia) and in patients treated concomitantly with class IA or III antiarrhythmic agents. Cautious use with ECG monitoring is advised in patients with other proarrhythmic conditions such as clinically significant bradycardia, congestive heart failure, acute myocardial ischemia, and atrial fibrillation. As QT prolongation may be a concentration-dependent effect, it is important that the recommended dosages or infusion rates of these drugs not be exceeded, particularly in patients with renal and/or hepatic impairment.

Quinolones may cause CNS stimulation manifested as tremors, agitation, restlessness, anxiety, confusion, hallucinations, paranoia, insomnia, toxic psychosis, and/or seizures. Benign intracranial hypertension has also been reported. Therapy with quinolones should be administered cautiously in patients with or predisposed to seizures or other CNS abnormalities. In addition, these patients should be advised to avoid the consumption of caffeine-containing products during therapy with some quinolones, most notably ciprofloxacin, enoxacin, and cinoxacin, since these agents can substantially reduce the clearance of caffeine and other methylxanthines, potentially resulting in severe CNS reactions.

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.

Quinolones have been reported to prolong the QT interval of the electrocardiogram in some patients. QT prolongation may potentiate the risk of ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes. The risk appears to be greatest with grepafloxacin and sparfloxacin (both are no longer marketed in the U.S.), although cardiovascular morbidity and mortality attributable to QT prolongation have also been reported rarely with others like gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Reported cases have primarily occurred in patients with advanced age, cardiac disease, electrolyte disturbances, and/or underlying medical problems for which they were receiving concomitant medications known to prolong the QT interval. Therapy with quinolones should be avoided in patients with known QT prolongation and/or uncorrected electrolyte disorders (hypokalemia or hypomagnesemia) and in patients treated concomitantly with class IA or III antiarrhythmic agents. Cautious use with ECG monitoring is advised in patients with other proarrhythmic conditions such as clinically significant bradycardia, congestive heart failure, acute myocardial ischemia, and atrial fibrillation. As QT prolongation may be a concentration-dependent effect, it is important that the recommended dosages or infusion rates of these drugs not be exceeded, particularly in patients with renal and/or hepatic impairment.

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.

Quinolones have been reported to prolong the QT interval of the electrocardiogram in some patients. QT prolongation may potentiate the risk of ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes. The risk appears to be greatest with grepafloxacin and sparfloxacin (both are no longer marketed in the U.S.), although cardiovascular morbidity and mortality attributable to QT prolongation have also been reported rarely with others like gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Reported cases have primarily occurred in patients with advanced age, cardiac disease, electrolyte disturbances, and/or underlying medical problems for which they were receiving concomitant medications known to prolong the QT interval. Therapy with quinolones should be avoided in patients with known QT prolongation and/or uncorrected electrolyte disorders (hypokalemia or hypomagnesemia) and in patients treated concomitantly with class IA or III antiarrhythmic agents. Cautious use with ECG monitoring is advised in patients with other proarrhythmic conditions such as clinically significant bradycardia, congestive heart failure, acute myocardial ischemia, and atrial fibrillation. As QT prolongation may be a concentration-dependent effect, it is important that the recommended dosages or infusion rates of these drugs not be exceeded, particularly in patients with renal and/or hepatic impairment.

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.

Quinolones have been reported to prolong the QT interval of the electrocardiogram in some patients. QT prolongation may potentiate the risk of ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes. The risk appears to be greatest with grepafloxacin and sparfloxacin (both are no longer marketed in the U.S.), although cardiovascular morbidity and mortality attributable to QT prolongation have also been reported rarely with others like gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Reported cases have primarily occurred in patients with advanced age, cardiac disease, electrolyte disturbances, and/or underlying medical problems for which they were receiving concomitant medications known to prolong the QT interval. Therapy with quinolones should be avoided in patients with known QT prolongation and/or uncorrected electrolyte disorders (hypokalemia or hypomagnesemia) and in patients treated concomitantly with class IA or III antiarrhythmic agents. Cautious use with ECG monitoring is advised in patients with other proarrhythmic conditions such as clinically significant bradycardia, congestive heart failure, acute myocardial ischemia, and atrial fibrillation. As QT prolongation may be a concentration-dependent effect, it is important that the recommended dosages or infusion rates of these drugs not be exceeded, particularly in patients with renal and/or hepatic impairment.

Quinolones have been reported to prolong the QT interval of the electrocardiogram in some patients. QT prolongation may potentiate the risk of ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes. The risk appears to be greatest with grepafloxacin and sparfloxacin (both are no longer marketed in the U.S.), although cardiovascular morbidity and mortality attributable to QT prolongation have also been reported rarely with others like gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Reported cases have primarily occurred in patients with advanced age, cardiac disease, electrolyte disturbances, and/or underlying medical problems for which they were receiving concomitant medications known to prolong the QT interval. Therapy with quinolones should be avoided in patients with known QT prolongation and/or uncorrected electrolyte disorders (hypokalemia or hypomagnesemia) and in patients treated concomitantly with class IA or III antiarrhythmic agents. Cautious use with ECG monitoring is advised in patients with other proarrhythmic conditions such as clinically significant bradycardia, congestive heart failure, acute myocardial ischemia, and atrial fibrillation. As QT prolongation may be a concentration-dependent effect, it is important that the recommended dosages or infusion rates of these drugs not be exceeded, particularly in patients with renal and/or hepatic impairment.

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.

Quinolones have been reported to prolong the QT interval of the electrocardiogram in some patients. QT prolongation may potentiate the risk of ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes. The risk appears to be greatest with grepafloxacin and sparfloxacin (both are no longer marketed in the U.S.), although cardiovascular morbidity and mortality attributable to QT prolongation have also been reported rarely with others like gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Reported cases have primarily occurred in patients with advanced age, cardiac disease, electrolyte disturbances, and/or underlying medical problems for which they were receiving concomitant medications known to prolong the QT interval. Therapy with quinolones should be avoided in patients with known QT prolongation and/or uncorrected electrolyte disorders (hypokalemia or hypomagnesemia) and in patients treated concomitantly with class IA or III antiarrhythmic agents. Cautious use with ECG monitoring is advised in patients with other proarrhythmic conditions such as clinically significant bradycardia, congestive heart failure, acute myocardial ischemia, and atrial fibrillation. As QT prolongation may be a concentration-dependent effect, it is important that the recommended dosages or infusion rates of these drugs not be exceeded, particularly in patients with renal and/or hepatic impairment.

Fluoroquinolones have neuromuscular blocking activity and may exacerbate muscle weakness in persons with myasthenia gravis. Postmarketing serious adverse events, including deaths and requirement for ventilatory support, have been associated with fluoroquinolones use in persons with myasthenia gravis. Fluoroquinolones should be avoided in patients with history of myasthenia gravis.

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.

Tendonitis and ruptures of the shoulder, hand, and Achilles tendons have been reported in patients receiving quinolones, both during and after treatment. Avoid the use of these agents in patients who have a history of tendon disorders or have experienced tendinitis or tendon rupture. Therapy with quinolones should be administered cautiously in patients with patients with kidney, heart, and lung transplant, since it may delay the recognition or confound the diagnosis of a quinolone-induced musculoskeletal effect. Factors that may independently increase the risk of tendon rupture include strenuous physical activity, renal failure, and previous tendon disorders such as rheumatoid arthritis. It is recommended to discontinue these agents if, at any time during therapy, pain, inflammation or rupture of a tendon develops and institute appropriate treatment.

The use of quinolones has been associated with an increased risk of peripheral neuropathy. Monitor closely and discontinue their use in patients experiencing symptoms of peripheral neuropathy. It is recommended to avoid these agents in patients who have previously experienced peripheral neuropathy.

Tendonitis and ruptures of the shoulder, hand, and Achilles tendons have been reported in patients receiving quinolones, both during and after treatment. Avoid the use of these agents in patients who have a history of tendon disorders or have experienced tendinitis or tendon rupture. Therapy with quinolones should be administered cautiously in patients with patients with kidney, heart, and lung transplant, since it may delay the recognition or confound the diagnosis of a quinolone-induced musculoskeletal effect. Factors that may independently increase the risk of tendon rupture include strenuous physical activity, renal failure, and previous tendon disorders such as rheumatoid arthritis. It is recommended to discontinue these agents if, at any time during therapy, pain, inflammation or rupture of a tendon develops and institute appropriate treatment.

Tendonitis and ruptures of the shoulder, hand, and Achilles tendons have been reported in patients receiving quinolones, both during and after treatment. Avoid the use of these agents in patients who have a history of tendon disorders or have experienced tendinitis or tendon rupture. Therapy with quinolones should be administered cautiously in patients with patients with kidney, heart, and lung transplant, since it may delay the recognition or confound the diagnosis of a quinolone-induced musculoskeletal effect. Factors that may independently increase the risk of tendon rupture include strenuous physical activity, renal failure, and previous tendon disorders such as rheumatoid arthritis. It is recommended to discontinue these agents if, at any time during therapy, pain, inflammation or rupture of a tendon develops and institute appropriate treatment.

Tendonitis and ruptures of the shoulder, hand, and Achilles tendons have been reported in patients receiving quinolones, both during and after treatment. Avoid the use of these agents in patients who have a history of tendon disorders or have experienced tendinitis or tendon rupture. Therapy with quinolones should be administered cautiously in patients with patients with kidney, heart, and lung transplant, since it may delay the recognition or confound the diagnosis of a quinolone-induced musculoskeletal effect. Factors that may independently increase the risk of tendon rupture include strenuous physical activity, renal failure, and previous tendon disorders such as rheumatoid arthritis. It is recommended to discontinue these agents if, at any time during therapy, pain, inflammation or rupture of a tendon develops and institute appropriate treatment.

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.

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.

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.

Crystalluria has been reported rarely during quinolone therapy. Although it is not expected to occur under normal circumstances with usual recommended dosages, patients who are dehydrated (e.g., due to severe diarrhea or vomiting) may be at increased risk and should be encouraged to consume additional amounts of liquid or given intravenous fluid to ensure an adequate urinary output. Alkalinity of the urine should be avoided, since it may also increase the risk of crystalluria. Renal function tests should be performed periodically during prolonged therapy (> 2 weeks).

The use of certain quinolones has been associated with disturbances in blood glucose homeostasis possibly stemming from effects on pancreatic beta cell ATP-sensitive potassium channels that regulate insulin secretion. Hypoglycemia and, less frequently, hyperglycemia have been reported, although the latter may also occur due to infection alone. Hypoglycemia has usually occurred in patients with diabetes receiving concomitant oral hypoglycemic agents and/or insulin. Administration of ciprofloxacin, levofloxacin, norfloxacin, and especially gatifloxacin in patients treated with sulfonylureas or other oral hypoglycemic agents has resulted in severe, refractory hypoglycemia and hypoglycemic coma. Elderly patients and patients with reduced renal function are particularly susceptible. Blood glucose should be monitored more closely whenever quinolones are prescribed to patients with diabetes. Gatifloxacin has been known to cause hypoglycemic episodes generally within the first 3 days of therapy and sometimes even after the first dose, while hyperglycemia usually occurs 4 to 10 days after initiation of therapy. Patients should be counseled to recognize symptoms of hypoglycemia such as headache, dizziness, drowsiness, nausea, tremor, weakness, hunger, excessive perspiration, and palpitations. If hypo- or hyperglycemia occur during quinolone therapy, patients should initiate appropriate remedial therapy immediately, discontinue the antibiotic, and contact their physician.

Crystalluria has been reported rarely during quinolone therapy. Although it is not expected to occur under normal circumstances with usual recommended dosages, patients who are dehydrated (e.g., due to severe diarrhea or vomiting) may be at increased risk and should be encouraged to consume additional amounts of liquid or given intravenous fluid to ensure an adequate urinary output. Alkalinity of the urine should be avoided, since it may also increase the risk of crystalluria. Renal function tests should be performed periodically during prolonged therapy (> 2 weeks).

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 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.

The following quinolones are known to be partially removed by hemodialysis and should be administered after dialysis: ciprofloxacin, enoxacin, gatifloxacin, levofloxacin, lomefloxacin, and ofloxacin.

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.

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.

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.

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.

Quinolones (except trovafloxacin, moxifloxacin, and nalidixic acid) and their metabolites are eliminated by the kidney. Patients with renal impairment may be at greater risk for adverse effects from quinolones, including nephrotoxicity, due to decreased drug clearance. Dosage adjustments may be necessary and modifications should be based on the degree of renal impairment and severity of infection in accordance with the individual product package labeling. Renal function tests should be performed periodically during therapy.

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.

Crystalluria has been reported rarely during quinolone therapy. Although it is not expected to occur under normal circumstances with usual recommended dosages, patients who are dehydrated (e.g., due to severe diarrhea or vomiting) may be at increased risk and should be encouraged to consume additional amounts of liquid or given intravenous fluid to ensure an adequate urinary output. Alkalinity of the urine should be avoided, since it may also increase the risk of crystalluria. Renal function tests should be performed periodically during prolonged therapy (> 2 weeks).