Clarithromycin: What to Know Before You Take It

5 WARNINGS AND PRECAUTIONS Severe Acute Hypersensitivity Reactions : Discontinue clarithromycin tablets if occurs ( 5.1 ) QT Prolongation : Avoid clarithromycin tablets in patients with known QT prolongation or receiving drugs known to prolong the QT interval, ventricular arrhythmia ( torsades 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 clarithromycin tablets with colchicine, some lipid-lowering agents, some calcium channel blockers, and other drugs ( 5.4 ) Risk of all-cause mortality one year or more after the end of treatment in patients with coronary artery disease. Balance this potential risk with the treatment benefits when prescribing clarithromycin tablets in these patients ( 5.5 ) Clostridium difficile associated diarrhea (CDAD) : Evaluate if diarrhea occurs ( 5.6 ) Embryo-Fetal Toxicity : Based on animal findings, clarithromycin tablets is not recommended for use in pregnant women except in clinical circumstances where no alternative therapy is appropriate ( 5.7 ) Exacerbation of myasthenia gravis has been reported in patients receiving clarithromycin tablets therapy ( 5.8 ) 5.1 Severe 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), Henoch-Schonlein purpura, and acute generalized exanthematous pustulosis, discontinue clarithromycin tablets therapy immediately and institute appropriate treatment. 5.2 QT Prolongation Clarithromycin tablets have 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 clarithromycin tablets. Fatalities have been reported. Avoid clarithromycin tablets 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 (e.g., quinidine, procainamide,disopyramide) or Class III (e.g., 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 clarithromycin tablets immediately if signs and symptoms of hepatitis occur. 5.4 Serious Adverse Reactions Due to Concomitant Use with Other Drugs Drugs metabolized by CYP3A4: Serious adverse reactions have been reported in patients taking clarithromycin tablets concomitantly with CYP3A4 substrates. These include colchicine toxicity with colchicine; markedly increased transaminases with lomitapide; rhabdomyolysis with simvastatin, lovastatin, and atorvastatin; hypoglycemia and cardiac arrhythmias (e.g., torsades de pointes) with disopyramide; and 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 clarithromycin tablets with caution when administered concurrently with medications that induce the cytochrome CYP3A4 enzyme. The use of clarithromycin with lomitapide, simvastatin, lovastatin, ergotamine, or dihydroergotamine is contraindicated [see Contraindications ( 4.5 , 4.6 ) and Drug Interactions ( 7 )]. Colchicine: Life-threatening and fatal drug interactions have been reported in patients treated with clarithromycin 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 clarithromycin tablets 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 clarithromycin tablets and colchicine is contraindicated in patients with renal or hepatic impairment [see Contraindications ( 4.4 ) and Drug Interactions ( 7 )] . Lomitapide: Concomitant use of clarithromycin with lomitapide is contraindicated [see Contraindications ( 4.5 )]. Lomitapide is metabolized by CYP3A4, and concomitant treatment with clarithromycin increases the plasma concentration of lomitapide, which increases the risk of elevation in transaminases [see Drug Interactions ( 7 )]. If treatment with clarithromycin cannot be avoided, therapy with lomitapide must be suspended during the course of treatment. HMG-CoA Reductase Inhibitors (statins): Concomitant use of clarithromycin tablets with lovastatin or simvastatin is contraindicated [see Contraindications ( 4.5 )] as these statins are extensively metabolized by CYP3A4, and concomitant treatment with clarithromycin increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Cases of rhabdomyolysis have been reported in patients taking clarithromycin concomitantly with these statins. If treatment with clarithromycin tablets cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment. Exercise caution when prescribing clarithromycin tablets with atorvastatin or pravastatin. In situations where the concomitant use of clarithromycin tablets 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. Oral Hypoglycemic Agents/Insulin: The concomitant use of clarithromycin tablets 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 )] . Oral Anticoagulants: There is a risk of serious hemorrhage and significant elevations in INR and prothrombin time when clarithromycin is co-administered with warfarin. Monitor INR and prothrombin times frequently while patients are receiving clarithromycin tablets and oral anticoagulants concurrently [see Drug Interactions ( 7 )] . Benzodiazepines: Increased sedation and prolongation of sedation have been reported with concomitant administration of clarithromycin and triazolobenzodiazepines, such as triazolam and midazolam [see Drug Interactions ( 7 )] . 5.5 All-Cause Mortality in Patients With Coronary Artery Disease 1 to 10 Years After Clarithromycin Exposure In one clinical trial evaluating treatment with clarithromycin on outcomes in patients with coronary artery disease, an increase in risk of all-cause mortality one year or more after the end of treatment was observed in patients randomized to receive clarithromycin. 1 Clarithromycin for treatment of coronary artery disease is not an approved indication. The cause of the increased risk has not been established. Other epidemiologic studies evaluating this risk have shown variable results [see Adverse Reactions ( 6.1 )] . Consider balancing this potential risk with the treatment benefits when prescribing Clarithromycin in patients who have suspected or confirmed coronary artery disease. 5.6 Clostridium difficile Associated Diarrhea Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including clarithromycin tablets, 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. 5.7 Embryo-Fetal Toxicity Based on findings from animal studies, Clarithromycin is not recommended for use in pregnant women except in clinical circumstances where no alternative therapy is appropriate. If clarithromycin tablets are 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 demonstrated adverse effects on pregnancy outcome and/or embryo fetal development, including fetal malformations, in pregnant animals administered oral clarithromycin [see Use in Specific Populations ( 8.1 )]. 5.8 Exacerbation of Myasthenia Gravis Exacerbation of symptoms of myasthenia gravis and new onset of symptoms of myasthenic syndrome has been reported in patients receiving clarithromycin tablets therapy. 5.9 Development of Drug Resistant Bacteria Prescribing clarithromycin tablets 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.