warnings and cautions
5 WARNINGS AND PRECAUTIONS Severe acute hypersensitivity reactions: Discontinue BIAXIN if occurs (5.1) QT prolongation: Avoid BIAXIN in patients with known QT prolongation or receiving drugs known to prolong the QT interval, ventricular arrhythmia (torsade de pointes), hypokalemia/hypomagnesemia, significant bradycardia, or taking Class IA or III antiarrhythmics (5.2) Hepatotoxicity: Discontinue if signs and symptoms of hepatitis occur (5.3) Serious adverse reactions can occur due to drug interactions of BIAXIN with colchicine, some HMG CoA reductase inhibitors, some calcium channel blockers, and other drugs (5.4) Clostridium difficile associated diarrhea (CDAD): Evaluate if diarrhea occurs (5.5) Embryofetal toxicity: BIAXIN should not be used in pregnant women except in clinical circumstances where no alternative therapy is appropriate (5.6) Exacerbation of myasthenia gravis (5.7) 5.1 Acute Hypersensitivity Reactions In the event of severe acute hypersensitivity reactions, such as anaphylaxis, Stevens-Johnson Syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS), and Henoch-Schonlein purpura, discontinue BIAXIN therapy immediately and institute appropriate treatment. 5.2 QT Prolongation BIAXIN has been associated with prolongation of the QT interval and infrequent cases of arrhythmia. Cases of torsades de pointes have been spontaneously reported during postmarketing surveillance in patients receiving BIAXIN. Fatalities have been reported. Avoid BIAXIN in the following patients: patients with known prolongation of the QT interval, ventricular cardiac arrhythmia, including torsades de pointes patients receiving drugs known to prolong the QT interval [see also Contraindications (4.2) ] patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia and in patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents. Elderly patients may be more susceptible to drug-associated effects on the QT interval [see Use in Specific Populations (8.5) ] . 5.3 Hepatotoxicity Hepatic dysfunction, including increased liver enzymes, and hepatocellular and/or cholestatic hepatitis, with or without jaundice, has been reported with clarithromycin. This hepatic dysfunction may be severe and is usually reversible. In some instances, hepatic failure with fatal outcome has been reported and generally has been associated with serious underlying diseases and/or concomitant medications. Symptoms of hepatitis can include anorexia, jaundice, dark urine, pruritus, or tender abdomen. Discontinue BIAXIN immediately if signs and symptoms of hepatitis occur. 5.4 Serious Adverse Reactions Due to Concomitant Use with Other Drugs Serious adverse reactions have been reported in patients taking BIAXIN concomitantly with CYP3A4 substrates. These include colchicine toxicity with colchicine; rhabdomyolysis with simvastatin, lovastatin, and atorvastatin; ; hypotension and with calcium channel blockers metabolized by CYP3A4 (e.g., verapamil, amlodipine, diltiazem, ). . Use BIAXIN with caution when administered concurrently with medications that induce the cytochrome CYP3A4 enzyme. The use of BIAXIN with simvastatin, lovastatin, ergotamine, or dihydroergotamine is contraindicated . Drugs metabolized by CYP3A4: Serious adverse reactions have been reported in patients taking BIAXIN concomitantly with CYP3A4 substrates. These include colchicine toxicity with colchicine; rhabdomyolysis with simvastatin, lovastatin, and atorvastatin; hypoglycemia with disopyramide; hypotension and acute kidney injury with calcium channel blockers metabolized by CYP3A4 (e.g., verapamil, amlodipine, diltiazem, nifedipine). Most reports of acute kidney injury with calcium channel blockers metabolized by CYP3A4 involved elderly patients 65 years of age or older. Use BIAXIN with caution when administered concurrently with medications that induce the cytochrome CYP3A4 enzyme. The use of BIAXIN with simvastatin, lovastatin, ergotamine, or dihydroergotamine is contraindicated [see Contraindications (4.5, 4.6) and Drug Interactions (7) ] . Life-threatening and fatal drug interactions have been reported in patients treated with BIAXIN and colchicine. Clarithromycin is a strong CYP3A4 inhibitor and this interaction may occur while using both drugs at their recommended doses. If co-administration of BIAXIN and colchicine is necessary in patients with normal renal and hepatic function, reduce the dose of colchicine. Monitor patients for clinical symptoms of colchicine toxicity. Concomitant administration of BIAXIN and colchicine is contraindicated in patients with renal or hepatic impairment . Colchicine: Life-threatening and fatal drug interactions have been reported in patients treated with BIAXIN and colchicine. Clarithromycin is a strong CYP3A4 inhibitor and this interaction may occur while using both drugs at their recommended doses. If co-administration of BIAXIN and colchicine is necessary in patients with normal renal and hepatic function, reduce the dose of colchicine. Monitor patients for clinical symptoms of colchicine toxicity. Concomitant administration of BIAXIN and colchicine is contraindicated in patients with renal or hepatic impairment [see Contraindications (4.4) and Drug Interactions (7) ] . Concomitant use of BIAXIN with lovastatin or simvastatin is contraindicated as these statins are extensively metabolized by CYP3A4, and concomitant treatment with BIAXIN increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Cases of rhabdomyolysis have been reported in patients taking BIAXIN concomitantly with these statins. If treatment with BIAXIN cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment. HMG-CoA Reductase Inhibitors (statins): Concomitant use of BIAXIN with lovastatin or simvastatin is contraindicated [see Contraindications (4.5) ] as these statins are extensively metabolized by CYP3A4, and concomitant treatment with BIAXIN increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Cases of rhabdomyolysis have been reported in patients taking BIAXIN concomitantly with these statins. If treatment with BIAXIN cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment. Exercise caution when prescribing BIAXIN with atorvastatin or pravastatin. In situations where the concomitant use of BIAXIN with atorvastatin or pravastatin cannot be avoided, atorvastatin dose should not exceed 20 mg daily and pravastatin dose should not exceed 40 mg daily. Use of a statin that is not dependent on CYP3A metabolism (e.g. fluvastatin) can be considered. It is recommended to prescribe the lowest registered dose if concomitant use cannot be avoided.Exercise caution when prescribing BIAXIN with atorvastatin or pravastatin. In situations where the concomitant use of BIAXIN with atorvastatin or pravastatin cannot be avoided, atorvastatin dose should not exceed 20 mg daily and pravastatin dose should not exceed 40 mg daily. Use of a statin that is not dependent on CYP3A metabolism (e.g. fluvastatin) can be considered. It is recommended to prescribe the lowest registered dose if concomitant use cannot be avoided. The concomitant use of BIAXIN and oral hypoglycemic agents and/or insulin can result in significant hypoglycemia. With certain hypoglycemic drugs such as nateglinide, pioglitazone, repaglinide and rosiglitazone, inhibition of CYP3A enzyme by clarithromycin may be involved and could cause hypoglycemia when used concomitantly. Careful monitoring of glucose is recommended . Oral Hypoglycemic Agents/Insulin: The concomitant use of BIAXIN and oral hypoglycemic agents and/or insulin can result in significant hypoglycemia. With certain hypoglycemic drugs such as nateglinide, pioglitazone, repaglinide and rosiglitazone, inhibition of CYP3A enzyme by clarithromycin may be involved and could cause hypoglycemia when used concomitantly. Careful monitoring of glucose is recommended [see Drug Interactions (7) ] . Quetiapine: Use quetiapine and clarithromycin concomitantly with caution. Co-administration could result in increased quetiapine exposure and quetiapine related toxicities such as somnolence, orthostatic hypotension, altered state of consciousness, neuroleptic malignant syndrome, and QT prolongation. Refer to quetiapine prescribing information for recommendations on dose reduction if co-administered with CYP3A4 inhibitors such as clarithromycin [see Drug Interactions (7) ] . There is a risk of serious hemorrhage and significant elevations in INR and prothrombin time when BIAXIN is co-administered with warfarin. Monitor INR and prothrombin times frequently while patients are receiving BIAXIN and oral anticoagulants concurrently . Oral Anticoagulants: There is a risk of serious hemorrhage and significant elevations in INR and prothrombin time when BIAXIN is co-administered with warfarin. Monitor INR and prothrombin times frequently while patients are receiving BIAXIN and oral anticoagulants concurrently [see Drug Interactions (7) ] . Increased sedation and prolongation of sedation have been reported with concomitant administration of BIAXIN and triazolobenzodiazepines, such as triazolam and midazolam . Benzodiazepines: Increased sedation and prolongation of sedation have been reported with concomitant administration of BIAXIN and triazolobenzodiazepines, such as triazolam and midazolam [see Drug Interactions (7) ] . 5.5 Clostridium difficile Associated Diarrhea Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including BIAXIN, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile . C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibacterial use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibacterial use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile , and surgical evaluation should be instituted as clinically indicated. 5.6 Embryofetal Toxicity Clarithromycin should not be used in pregnant women except in clinical circumstances where no alternative therapy is appropriate. If BIAXIN is used during pregnancy, or if pregnancy occurs while the patient is taking this drug, the patient should be apprised of the potential hazard to the fetus. Clarithromycin has demonstrated adverse effects on pregnancy outcome and/or embryo-fetal development in monkeys, rats, mice, and rabbits at doses that produced plasma levels 2 times to 17 times the serum levels achieved in humans treated at the maximum recommended human doses [see Use in Specific Populations (8.1) ] . 5.7 Exacerbation of Myasthenia Gravis Exacerbation of symptoms of myasthenia gravis and new onset of symptoms of myasthenic syndrome has been reported in patients receiving BIAXIN therapy. 5.8 Development of Drug Resistant Bacteria Prescribing BIAXIN in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.