Before taking clarithromycin,
tell your doctor and pharmacist if you are allergic to clarithromycin, azithromycin (Zithromax, Zmax), dirithromycin (Dynabac) (not available in the U.S.), erythromycin (E.E.S., E-Mycin, Erythrocin), telithromycin (Ketek), any other medications, or any of the ingredients in clarithromycin tablets or suspension. Ask your pharmacist for a list of the ingredients.
tell your doctor if you are taking astemizole (Hismanal) (not available in the U.S.),cisapride (Propulsid), colchicine (Colcrys), dihydroergotamine (DHE 45, Migranal), ergotamine (Ergomar, in Cafergot, in Migergot), lovastatin (Mevacor, in Advicor) pimozide (Orap), simvastatin (Zocor, in Vytorin), or terfenadine (Seldane) (not available in the U.S.). Your doctor will probably tell you not to take clarithromycin if you are taking one or more of these medications.
tell your doctor if you have or have ever had prolonged QT interval (a rare heart problem that may cause fainting or irregular heartbeat) or ventricular arrhythmia (abnormal heart rhythms) or if you have ever had jaundice (yellowing of the skin or eyes) or other liver problems while taking clarithromycin, Your doctor will probably tell you not to take clarithromycin.
tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants ('blood thinners') such as warfarin (Coumadin); certain benzodiazepines such as alprazolam (Xanax), midazolam (Versed), and triazolam (Halcion); bromocriptine (Parlodel); calcium channel blockers such as amlodipine (Norvasc, in Caduet, in Lotrel), diltiazem (Cardizem, Dilacor, Tiazac), and verapamil (Calan, Covera, Isoptin, Verelan, in Tarka); carbamazepine (Tegretol); certain medications for HIV such as atazanavir (Reyataz), didanosine (Videx), efavirenz (Sustiva, in Atripla), nevirapine (Viramune), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), saquinavir (Invirase), and zidovudine (AZT, Retrovir); certain medications for irregular heartbeat such as amiodarone (Cordarone, Pacerone), disopyramide (Norpace), dofetilide (Tikosyn), procainamide (Procanbid), quinidine, and sotalol (Betapace); cholesterol-lowering medications (statins) such as atorvastatin (Lipitor, in Caduet) and pravastatin (Pravachol); cilostazol (Pletal); cyclosporine (Neoral, Sandimmune); darifenacin (Enablex); digoxin (Digitek, Lanoxin); erlotinib (Tarceva); eszopiclone (Lunesta); fluconazole (Diflucan); insulin; itraconazole (Sporanox); methylprednisolone (Medrol); omeprazole (Prilosec); oral medications for diabetes such as nateglinide (Starlix), pioglitazone (Actos, in Actoplus Met, in Duetact), repaglinide (Prandin, in Prandimet), and rosiglitazone (Avandia, in Avandamet, in Avandaryl); phenytoin (Dilantin); ranitidine (Zantac); rifabutin (Mycobutin); rifampin (Rifadin, Rifamate, rifampicin, Rimactane); rifapentine (Priftin); sildenafil (Viagra); tacrolimus (Prograf); theophylline (Theo-Dur); tadalafil (Cialis, Adcirca); tolterodine (Detrol); valproate (Depacon); valproic acid (Depakote); vardenafil (Levitra); and vinblastine. Many other medications may also interact with clarithromycin, so tell your doctor about all the medications you are taking, even those that do not appear on this list. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have a low level of magnesium or potassium in your blood, or if you have or have ever had an irregular heartbeat, or kidney, or liver disease.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking clarithromycin, call your doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking clarithromycin.