Clarithromycin

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Aug 07, 2024

Warnings

Clarithromycin Risks, Warnings, and Complications

Clarithromycin can cause or worsen health problems in some people. Talk to your doctor or pharmacist about other treatment options if you are at a higher risk of adverse effects from this drug.

Serious Allergic Reaction: Rarely, clarithromycin can cause a severe acute hypersensitivity reaction, including anaphylaxis (throat closing) and severe skin reactions (toxic epidermal necrolysis, Stevens-Johnson Syndrome, drug rash with eosinophilia and systemic symptoms (DRESS), acute generalized exanthematous pustulosis, and Henoch-Schonlein purpura). Stop taking clarithromycin and seek emergency medical care if you develop skin rash, hives, itching, peeling, blistering, swelling, or difficulty breathing.
QT Prolongation: Clarithromycin can cause prolongation of the QT interval (changes in the heart’s electrical system) and arrhythmia (heart rhythm abnormalities), including rare abnormalities such as torsades de pointes, which can be fatal. Before starting clarithromycin therapy, tell your doctor if you have prolongation of the QT interval, cardiac arrhythmias, hypokalemia (low potassium), or hypomagnesemia (low magnesium). Also tell your doctor if you take other medications that are known to cause QT prolongation. Elderly people are at a higher risk of drug-associated prolonged QT interval.
Liver Toxicity: There are reports of liver dysfunction, elevated liver enzymes, and hepatitis (liver inflammation) in people treated with clarithromycin. This hepatic dysfunction can be severe but is usually temporary and goes away once treatment is stopped. However, there is a risk of liver failure that can be fatal, especially in people with other serious underlying health conditions or those taking other medications that can cause liver injury. Tell your doctor without delay if you develop nausea, loss of appetite, yellowing of the skin or eyes, dark urine, itching, and right upper stomach pain.
Drug Interactions: Serious adverse reactions can occur in people taking clarithromycin with certain other medications, including colchicine, lomitapide, statin drugs (simvastatin, lovastatin, atorvastatin), disopyramide, calcium channel blockers (verapamil, diltiazem, amlodipine, nifedipine), insulin and oral diabetes medications, quetiapine, oral anticoagulants, and benzodiazepines. Give your doctor and pharmacist a complete list of your medications before starting clarithromycin to avoid potentially dangerous interactions.
Increased Mortality in People with Coronary Artery Disease: One clinical trial found that clarithromycin treatment in people with heart disease can lead to an increased risk of all-cause death and sudden cardiac death. The reason for this increased risk is unclear. Other studies have shown variable results. Your doctor will carefully weigh the benefits versus risks of clarithromycin therapy if you have known heart disease.
Clostridium difficile Associated Diarrhea: All antibacterial agents, including clarithromycin, can cause a serious intestinal condition called Clostridium difficile associated diarrhea (CDAD). This can range in severity from mild diarrhea to potentially fatal colitis. It occurs due to changes in the gut microbiome after treatment with antibiotics, which can allow overgrowth of a bacteria called C. difficile which produces toxins that cause CDAD. Symptoms can occur up to 2 months or more after completing antibiotic treatment and include severe watery or bloody diarrhea with or without fever and stomach cramps. Seek emergency medical care if you develop severe diarrhea after antibiotic therapy.
Fetal Toxicity: Animal studies indicate that clarithromycin may be harmful to an unborn baby. This antibiotic is not recommended for use during pregnancy except where no alternatives are available.
Exacerbation of Myasthenia Gravis: There are reports of worsening or new-onset symptoms of myasthenia gravis in people who received clarithromycin therapy. Tell your doctor if you have a history of myasthenia gravis. Seek medical care without delay if you develop muscle weakness after taking clarithromycin.
Drug Resistant Bacteria: Clarithromycin is an antibiotic and will not treat a cold, flu, or other viral infections. Using antibiotics when they are not needed or using them for prolonged or repeated periods can lead to antibiotic resistance in bacteria. This can make bacterial infections harder to treat in the future.

Precautions Before Starting Clarithromycin

Tell your doctor if you are allergic to clarithromycin, any of the active or inactive ingredients in clarithromycin formulations, other antibiotics, or any other drugs. Your pharmacy can give you a list of ingredients.

Give your doctor and pharmacist a complete list of all the drugs you are taking, including prescription medications, over-the-counter medicines, vitamins, supplements, and herbal products. This can help avoid possible interactions.

Give your doctor a complete medical history. Clarithromycin may not be safe for people with certain medical conditions such as jaundice or liver disease after taking clarithromycin, prolonged QT interval, low potassium, low magnesium, coronary artery disease, irregular heart beat, slow heartbeat, low white blood cell count, myasthenia gravis, severe kidney problems or reduced kidney function, or liver disease.

Tell your doctor if you are pregnant, could be pregnant, plan to get pregnant soon, or are breast-feeding. This drug passes into breast milk in small amounts.

Precautions During Use of Clarithromycin

Keep all your medical and lab appointments while taking clarithromycin.

Clarithromycin can cause dizziness, confusion, and disorientation in some people. Do not drive, operate machinery, or do other hazardous activities until you know how it affects you.

Tell your doctor immediately if you become pregnant while on clarithromycin.

Tell all your doctors you are on clarithromycin before any surgery, including dental procedures.

Clarithromycin Drug Interactions

Certain drugs can affect how clarithromycin works. Possible interactions with other medicines can increase the risk of severe adverse effects. You should not take clarithromycin if you are on these medications:

Colchicine (Colcrys, Mitigare) in people with kidney or liver disease
Cisapride (Propulsid)
Lomitapide (Juxtapid)
Dihydroergotamine (D.H.E. 45, Migranal) and ergotamine (Ergomar, in Cafergot, in Migergot)
Lovastatin (in Advicor) and simvastatin (Zocor, in Vytorin)
Pimozide (Orap)

The following medications can also have possible drug interactions with clarithromycin:

Anticoagulants or blood thinners such as warfarin (Coumadin, Jantoven)
Dopamine receptor agonists such as bromocriptine (Parlodel)
Certain benzodiazepine drugs such as midazolam, alprazolam (Xanax), and triazolam (Halcion)
Non-benzodiazepine hypnotic drugs such as eszopiclone (Lunesta)
Calcium channel blockers including diltiazem (Cardizem, Tiazac, Cartia), amlodipine (Norvasc, in Lotrel, in Caduet), nifedipine (Afeditab CR, Adalat), and verapamil (Verelan, Calan, in Tarka)
Antiseizure drugs such as phenobarbital, phenytoin (Dilantin, Phenytek), valproate (Depacon), and carbamazepine (Tegretol, Epitol, Teril)
Gout medications such as colchicine (Mitigare, Colcrys)
HIV medications such as efavirenz (Sustiva, in Atripla), atazanavir (Reyataz), didanosine (Videx), etravirine (Intelence), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), nevirapine (Viramune), saquinavir (Invirase), zidovudine (Retrovir, AZT), and maraviroc (Selzentry)
Certain medications used to cardiac arrhythmias such as disopyramide (Norpace), dofetilide (Tikosyn), amiodarone (Pacerone), procainamide, sotalol (Sorine, Betapace), and quinidine (in Nuedexta)
Medications prescribed for high cholesterol (statins), including atorvastatin (Lipitor, in Caduet) and pravastatin (Pravachol)
Antiplatelet medications such as cilostazol
Immunosuppressants such as cyclosporine (Neoral, Gengraf, Sandimmune) and tacrolimus (Prograf, Astagraf)
Medications prescribed for bladder conditions, such as darifenacin (Enablex) and tolterodine (Detrol)
Heart medications such as digoxin (Lanoxin, Digitek)
Cancer medications such as erlotinib (Tarceva) and vinblastine
Antifungals such as fluconazole (Diflucan) and itraconazole (Sporanox, Onmel)
Insulin and oral anti-diabetes medications such as pioglitazone (Actos, in Actoplus Met, in Duetact), nateglinide (Starlix), repaglinide (Prandin, in Prandimet), and rosiglitazone (Avandia, in Avandamet, in Avandaryl)
Corticosteroids such as methylprednisolone (Medrol)
Proton pump inhibitors such as omeprazole (Prilosec)
Medications used to treat psychiatric conditions such as quetiapine (Seroquel)
Antitubercular drugs such as rifabutin (Mycobutin), rifampin (Rifadin, Rimactane, in Rifater, in Rifamate), and rifapentine (Priftin)
PDE5 inhibitors such as sildenafil (Viagra, Revatio), vardenafil (Levitra, Staxyn), and tadalafil (Adcirca, Cialis)
Medications used to treat lung conditions such as theophylline (Theo-24, Elixophyllin, Theochron)
Herbal products such as St. John's wort

The above list may not describe all the potential interactions of clarithromycin. Give your doctor or pharmacist a complete list of your medications, including prescription medications, over-the-counter medications, dietary supplements, and herbal remedies. Also, tell your healthcare professional if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription medications.

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