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Biaxin Side Effects

Generic name: clarithromycin

Medically reviewed by Last updated on Sep 14, 2023.

Note: This document contains side effect information about clarithromycin. Some dosage forms listed on this page may not apply to the brand name Biaxin.

Applies to clarithromycin: oral powder for suspension, oral tablet, oral tablet extended release.

Serious side effects of Biaxin

Along with its needed effects, clarithromycin (the active ingredient contained in Biaxin) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking clarithromycin:

Less common


Incidence not known

Other side effects of Biaxin

Some side effects of clarithromycin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Incidence not known

For Healthcare Professionals

Applies to clarithromycin: oral powder for reconstitution, oral tablet, oral tablet extended release.


The most common side effects were abdominal pain/discomfort, diarrhea, nausea, vomiting, and dysgeusia/taste perversion.

In immunocompromised patients treated with higher doses of this drug (1 to 2 g/day), the most common side effects were nausea, vomiting, taste perversion, abdominal pain, diarrhea, rash, flatulence, headache, constipation, hearing disturbance, increased AST, and increased ALT.[Ref]

Nervous system

Very common (10% or more): Dysgeusia/taste perversion (up to 16%)

Common (1% to 10%): Headache, dizziness

Uncommon (0.1% to 1%): Loss of consciousness, dyskinesia, somnolence, hearing impaired, tinnitus, tremor, vertigo

Frequency not reported: New onset of symptoms of myasthenic syndrome, exacerbation of symptoms of myasthenia gravis, hearing disturbance, muzziness

Postmarketing reports: Convulsions, ageusia, parosmia/smell perversion, anosmia, paresthesia, deafness, hyperkinesia[Ref]

Deafness was reported mainly in elderly women and was usually reversible.[Ref]


Very common (10% or more): Nausea (up to 12.3%)

Common (1% to 10%): Diarrhea, vomiting, abdominal pain/discomfort, dyspepsia/heartburn, flatulence, oral candidiasis/moniliasis, constipation

Uncommon (0.1% to 1%): Glossitis, stomatitis, esophagitis, gastroesophageal reflux disease, gastritis, proctalgia, abdominal distension, dry mouth, eructation, gastroenteritis, gastrointestinal hemorrhage, bleeding gums, bloodstained stools

Frequency not reported: Clostridium difficile-associated diarrhea (ranging from mild diarrhea to fatal colitis), pancreatitis

Postmarketing reports: Acute pancreatitis, tongue discoloration, tooth discoloration, pseudomembranous colitis, enteritis[Ref]

The incidence of dry mouth was similar for patients treated with 1 to 2 g/day, but was generally about 3 to 4 times as frequent for those treated with 4 g/day.

Severity of pseudomembranous colitis has ranged from mild to life-threatening.

Tooth discoloration was usually reversible with professional dental cleaning after the drug was stopped.[Ref]


These side effects are specific to the IV formulation.

Very common (10% or more): Injection site phlebitis

Common (1% to 10%): Injection site pain, injection site inflammation, tenderness at site of administration

Frequency not reported: Vessel puncture site pain


Elevated AST (greater than 5 times the upper limit of normal [5 x ULN]) and ALT (greater than 5 x ULN) were reported in up to 4% and up to 3% of patients, respectively.

Hepatic dysfunction (sometimes severe and usually reversible), including increased liver enzymes, and hepatocellular and/or cholestatic hepatitis, with or without jaundice have been reported. In some instances, hepatic failure with fatal outcome has been reported and generally has been associated with serious underlying diseases (e.g., preexisting liver disease) and/or concomitant medications (e.g., hepatotoxic agents).

Drug-induced hepatotoxicity was rare and typically associated with higher doses (1 to 2 g/day) and high serum drug levels. The enzyme elevation pattern was usually cholestatic with minimal elevations of AST and ALT.[Ref]

Common (1% to 10%): Elevated AST, elevated ALT, abnormal liver function test

Uncommon (0.1% to 1%): Cholestasis, hepatitis (symptoms included anorexia, jaundice, dark urine, pruritus, tender abdomen), increased blood bilirubin, elevated GGT, elevated direct bilirubin, hepatic dysfunction (including increased liver enzymes), hepatitis and cholestasis with or without jaundice

Frequency not reported: Hepatocellular and/or cholestatic hepatitis (with or without jaundice), drug-induced hepatotoxicity, fulminant hepatic failure

Postmarketing reports: Hepatic failure, hepatocellular jaundice, adverse reactions related to hepatic dysfunction, abnormal hepatic function, liver abnormalities[Ref]


Common (1% to 10%): Anaphylactoid reaction

Uncommon (0.1% to 1%): Hypersensitivity, allergic reactions

Postmarketing reports: Anaphylactic reaction, angioedema[Ref]

Allergic reactions have ranged from urticaria and mild skin eruptions to rare cases of anaphylaxis.

A 92-year-old female admitted for heart failure and a right upper lobe infiltrate was started on clarithromycin 500 mg. The following day, this drug was discontinued and IV antibiotics were initiated due to persisting fever. She received only 1 dose of this drug. On day 6 of the hospitalization, the patient was afebrile, IV antibiotics were stopped, and this drug was again started. Two hours after the dose, the patient developed swelling in her lips, jaw, tongue, mouth, and face. The patient was given diphenhydramine and the clarithromycin was discontinued. She was discharged the following day.[Ref]


Common (1% to 10%): Vasodilation, phlebitis

Uncommon (0.1% to 1%): ECG QT prolonged, cardiac arrest, atrial fibrillation, extrasystoles, palpitations

Rare (0.01% to 0.1%): Arrhythmia

Frequency not reported: QT interval prolongation

Postmarketing reports: Ventricular arrhythmia, ventricular tachycardia, torsades de pointes, hemorrhage[Ref]


Decreased WBC (less than 1 x 10[9]/L), platelet count (less than 50 x 10[9]/L), and hemoglobin (less than 8 g/dL) were reported in up to 4%, up to 4%, and 3% of patients, respectively.[Ref]

Common (1% to 10%): Decreased WBC, decreased platelet count, decreased hemoglobin

Uncommon (0.1% to 1%): Leukopenia, neutropenia, thrombocythemia, eosinophilia, increased prothrombin time

Frequency not reported: Granulocytopenia, reduction in prothrombin time

Postmarketing reports: Thrombocytopenia, agranulocytosis, prolonged prothrombin time, decreased WBC count, increased INR[Ref]


Common (1% to 10%): Rash, hyperhidrosis, pruritus

Uncommon (0.1% to 1%): Urticaria, dermatitis bullous, maculopapular rash, cellulitis, pustular rash (non-urticarial), stained fingernails

Postmarketing reports: Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS), Henoch-Schonlein purpura, acne, erysipelas, erythrasma[Ref]


Many reports of extended-release tablets in the stool occurred in patients with anatomic (including ileostomy or colostomy) or functional gastrointestinal disorders with shortened gastrointestinal transit times. In several reports, tablet residues occurred in the context of diarrhea.

Colchicine toxicity has been reported with concomitant use of this drug and colchicine, especially in the elderly; some occurred in patients with renal dysfunction. Death occurred in some such patients.[Ref]

Common (1% to 10%): Infection, candidiasis, pyrexia/fever, asthenia

Uncommon (0.1% to 1%): Malaise, chest pain, chills, fatigue, thirst, abnormal albumin globulin ratio, body aches and pains, flushing, accidental injury, flu syndrome

Postmarketing reports: Otitis media, extended-release tablets in the stool, colchicine toxicity[Ref]


The incidence of insomnia was similar for patients treated with 1 to 2 g/day, but was generally about 3 to 4 times as frequent for those treated with 4 g/day.

Psychotic disorder, confusional state, depersonalization, depression, disorientation, manic behavior, hallucination, abnormal behavior, and/or abnormal dreams usually resolved after the drug was stopped.[Ref]

Common (1% to 10%): Insomnia

Uncommon (0.1% to 1%): Anxiety, nervousness, screaming, depression, sleep disturbance

Frequency not reported: Behavioral changes, nightmares, psychosis

Postmarketing reports: Psychotic disorder, confusional state, depersonalization, disorientation, hallucination, depression, manic behavior, abnormal behavior, abnormal dreams[Ref]


Common (1% to 10%): Increased alkaline phosphatase

Uncommon (0.1% to 1%): Anorexia, decreased appetite, increased blood LDH

Postmarketing reports: Hypoglycemia[Ref]

Increased alkaline phosphatase (greater than 5 x ULN) was reported in up to 2% of patients.

Hypoglycemia has been reported in patients receiving oral hypoglycemic agents or insulin.[Ref]


Common (1% to 10%): Dyspnea, rhinitis, increased cough, pharyngitis, asthma

Uncommon (0.1% to 1%): Epistaxis, pulmonary embolism

Frequency not reported: Laryngismus[Ref]

The incidence of dyspnea was similar for patients treated with 1 to 2 g/day, but was generally about 3 to 4 times as frequent for those treated with 4 g/day.[Ref]


Uveitis was reported primarily in patients treated with concomitant rifabutin; most cases were reversible.

A case of corneal opacities was reported in a patient with AIDS and Mycobacterium avium complex bacteremia. The patient's ocular signs and symptoms resolved upon substitution with azithromycin.[Ref]

Common (1% to 10%): Conjunctivitis

Uncommon (0.1% to 1%): Photophobia

Very rare (less than 0.01%): Uveitis

Frequency not reported: Corneal opacities[Ref]


Uncommon (0.1% to 1%): Elevated BUN, elevated serum creatinine, increased blood urea, increased blood creatinine

Frequency not reported: Acute renal failure

Postmarketing reports: Interstitial nephritis, renal failure[Ref]

Elevated BUN (greater than 50 mg/dL) was reported in less than 1% of patients.[Ref]


Uncommon (0.1% to 1%): Myalgia, muscle spasms, nuchal rigidity, musculoskeletal stiffness, arthralgia, back pain

Postmarketing reports: Myopathy, rhabdomyolysis

In some cases of rhabdomyolysis, this drug was coadministered with statins, fibrates, colchicine, or allopurinol.


Uncommon (0.1% to 1%): Vaginal infection

Postmarketing reports: Abnormal urine color (associated with hepatic failure), dysuria[Ref]


Rare (0.01% to 0.1%): Leukocytoclastic vasculitis[Ref]

Frequently asked questions


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8. Hamedani P, Ali J, Hafeez S, et al. (1991) "The safety and efficacy of clarithromycin in patients with legionella pneumonia." Chest, 100, p. 1503-6

9. Peters D, Clissold S (1992) "Clarithromycin: a review of its antimicrobial activity, pharmacokinetic properties and therapeutic potential." Drugs, 44, p. 117-64

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.