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Side Effects of Biaxin (clarithromycin)

Does Biaxin (clarithromycin) cause side effects?

Biaxin (clarithromycin) is a macrolide antibiotic used to treat susceptible bacteria causing the following infections:

Biaxin has been used in combination with omeprazole/sodium bicarbonate (Prilosec) in treating H. Pylori that causes stomach ulcers. Biaxin is effective against a wide variety of bacteria, such as

Like all macrolide antibiotics, Biaxin prevents bacteria from growing by interfering with their ability to make proteins. 

Due to the differences in the way proteins are made in bacteria and humans, the macrolide antibiotics do not interfere with production of proteins in humans. 

Common side effects of Biaxin include

Serious but rare side effects of Biaxin include

Drug interactions of Biaxin include colchicine, simvastatin, lovastatin, atorvastatin, verapamil, amlodipine, and diltiazem because Biaxin reduces the activity of liver enzymes that breakdown these drugs.

This leads to increased blood levels and side effects from the affected drugs.

Safe use of Biaxin in pregnancy has not been established. There are no adequate studies of Biaxin in pregnant women. 

Biaxin is excreted in breast milk. Consult your doctor before breastfeeding. 

What are the important side effects of Biaxin (clarithromycin)?

Clarithromycin generally is well tolerated, and side effects usually are mild and transient. Common side effects of clarithromycin are:

Other important side effects which are rare, but serious include:

Clarithromycin should be avoided by patients known to be allergic to clarithromycin or other chemically-related macrolide antibiotics, such as erythromycin. Treatment with clarithromycin and other antibiotics can alter the normal bacteria flora of the colon and permit overgrowth of C. difficile, a bacterium responsible for pseudomembranous colitis.

Patients who develop pseudomembranous colitis as a result of antibiotics treatment may experience

Biaxin (clarithromycin) side effects list for healthcare professionals

The following serious adverse reactions are described below and elsewhere in the labeling:

  • Acute Hypersensitivity Reactions
  • QT Prolongation
  • Hepatotoxicity
  • Serious Adverse Reactions Due to Concomitant Use with Other Drugs
  • Clostridium difficile Associated Diarrhea
  • Exacerbation of Myasthenia Gravis

Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

Based on pooled data across all indications, the most frequent adverse reactions for both adult and pediatric populations observed in clinical trials are

  • abdominal pain,
  •  diarrhea,
  • nausea,
  • vomiting and
  • dysgeusia.

Also reported were

The subsequent subsections list the most common adverse reactions for prophylaxis and treatment of mycobacterial infections and duodenal ulcer associated with H. pylori infection. In general, these profiles are consistent with the pooled data described above.

Prophylaxis Of Mycobacterial Infections

In AIDS patients treated with Biaxin over long periods of time for prophylaxis against M. avium, it was often difficult to distinguish adverse reactions possibly associated with Biaxin administration from underlying HIV disease or intercurrent illness. Median duration of treatment was 10.6 months for the Biaxin group and 8.2 months for the placebo group.

Table 4: Incidence Rates (%) of Selected Adverse Reactionsa in Immunocompromised Adult Patients Receiving Prophylaxis Against M. avium Complex

Body Systemb Adverse Reaction Biaxin
(n=339) %		 Placebo
(n=339) %
Body as a Whole
Abdominal pain 5% 4%
Headache 3% 1%
Digestive
Diarrhea 8% 4%
Dyspepsia 4% 3%
Flatulence 2% 1%
Nausea 11% 7%
Vomiting 6% 3%
Skin & Appendages
Rash 3% 4%
Special Senses
Taste Perversion 8%c 0.3%
a Includes those events possibly or probably related to study drug and excludes concurrent conditions
b 2% or greater Adverse Reaction Incidence Rates for either treatment group
c Significant higher incidence compared to the placebo-treated group

Changes In Laboratory Values

Selected laboratory adverse experiences that were reported during therapy in greater than 2 % of adult patients treated with Biaxin in a randomized double-blind clinical trial involving 682 patients are presented in Table 5.

In immunocompromised patients receiving prophylaxis against M. avium, evaluations of laboratory values were made by analyzing those values outside the seriously abnormal value (i.e., the extreme high or low limit) for the specified test.

Table 5: Percentage of Patientsa Exceeding Extreme Laboratory Values in Patients Receiving Prophylaxis Against M. avium Complex

    Biaxin 500 mg twice a day Placebo
WBC Count <1 x 109/L 2/103 (4%) 0/95
SGOT >5 x ULNb 7/196 (4%) 5/208 (2%)
SGPT >5 x ULNb 6/217 (3%) 4/232 (2%)
a Includes only patients with baseline values within the normal range or borderline high (hematology variables) and within normal range or borderline low (chemistry variables)
b ULN= Upper Limit of Normal

Treatment Of Mycobacterial Infections

  • The adverse reaction profiles for both the 500 mg and 1000 mg twice a day dose regimens were similar.
  • In AIDS patients and other immunocompromised patients treated with the higher doses of Biaxin over long periods of time for mycobacterial infections, it was often difficult to distinguish adverse reactions possibly associated with Biaxin administration from underlying signs of HIV disease or intercurrent illness.
  • The following analysis summarizes experience during the first 12 weeks of therapy with Biaxin.
  • Data are reported separately for trial 1 (randomized, double-blind) and trial 2 (openlabeled, compassionate use) and also combined. Adverse reactions were reported less frequently in trial 2, which may be due in part to differences in monitoring between the two studies.
  • In adult patients receiving Biaxin 500 mg twice a day, the most frequently reported adverse reactions, considered possibly or possibly related to study drug, with an incidence of 5% or greater, are listed below (Table 6).
  • Approximately 8% of the patients who received 500 mg twice a day and 12% of the patients who received 1000 mg twice a day discontinued therapy due to drug related adverse reactions during the first 12 weeks of therapy; adverse reactions leading to discontinuation in at least 2 patients included
    • nausea,
    • vomiting,
    • abdominal pain,
    • diarrhea,
    • rash, and
    • asthenia.

Table 6: Selected Treatment-Relateda Adverse Reaction Incidence Rates (%) in Immunocompromised Adult Patients During the First 12 Weeks of Therapy with 500 mg Twice a Day Biaxin Dose

Adverse Reaction Trial 1
(n=53)		 Trial 2
(n=255)		 Combined
(n=308)
Abdominal Pain 8 2 3
Diarrhea 9 2 3
Flatulence 8 0 1
Headache 8 0 2
Nausea 28 9 12
Rash 9 2 3
Taste Perversion 19 0 4
Vomiting 25 4 8
a Includes those events possibly or probably related to study drug and excludes concurrent conditions

  • A limited number of pediatric AIDS patients have been treated with Biaxin suspension for mycobacterial infections.
  • The most frequently reported adverse reactions excluding those due to the patient's concurrent conditions were consistent with those observed in adult patients.
Changes In Laboratory Values
  • In the first 12 weeks of starting on Biaxin 500 mg twice a day, 3% of patients has SGOT increases and 2% of patients has SGPT increases > 5 times the upper limit of normal in trial 2 (469 enrolled adult patients) while trial 1 (154 enrolled patients) had no elevation of transaminases.
  • This includes only patients with baseline values within the normal range or borderline low.

Duodenal Ulcer Associated With H. pylori Infection

  • In clinical trials using combination therapy with Biaxin plus omeprazole and amoxicillin, no adverse reactions specific to the combination of these drugs have been observed.
  • Adverse reactions that have occurred have been limited to those that have been previously reported with Biaxin, omeprazole or amoxicillin.
  • The adverse reaction profiles are shown below (Table 7) for four randomized double-blind clinical trials in which patients received the combination of Biaxin 500 mg three times a day, and omeprazole 40 mg daily for 14 days, followed by omeprazole 20 mg once a day, (three studies) or 40 mg once a day (one study) for an additional 14 days.
  • Of the 346 patients who received the combination, 3.5% of patients discontinued drug due to adverse reactions.

Table 7: Adverse Reactions with an Incidence of 3% or Greater

Adverse Reaction Biaxin + Omeprazole
(n=346) % of Patients		 Omeprazole
(n=355) % of Patients		 Biaxin
(n=166) % of Patientsa
Taste Perversion 15 1 16
Nausea 5 1 3
Headache 5 6 9
Diarrhea 4 3 7
Vomiting 4 <1 1
Abdominal Pain 3 2 1
Infection 3 4 2
a Only two of four studies

Changes In Laboratory Values

Changes in laboratory values with possible clinical significance in patients taking Biaxin and omeprazole in four randomized double-blind trials in 945 patients are as follows:

  • Hepatic: elevated direct bilirubin <1%; GGT <1%; SGOT (AST) <1%; SGPT (ALT) <1%, Renal: elevated serum creatinine <1%.

Less Frequent Adverse Reactions Observed During Clinical Trials Of Clarithromycin

Based on pooled data across all indications, the following adverse reactions were observed in clinical trials with clarithromycin at a rate less than 1%:

Gastrointestinal Adverse Reactions

  • In the acute exacerbation of chronic bronchitis and acute maxillary sinusitis studies overall gastrointestinal adverse reactions were reported by a similar proportion of patients taking either Biaxin Filmtab or Biaxin XL Filmtab; however, patients taking Biaxin XL Filmtab reported significantly less severe gastrointestinal symptoms compared to patients taking Biaxin Filmtab.
  • In addition, patients taking Biaxin XL Filmtab had significantly fewer premature discontinuations for drug-related gastrointestinal or abnormal taste adverse reactions compared to Biaxin Filmtab.

All-Cause Mortality In Patients With Coronary Artery Disease 1 To 10 Years Following Biaxin 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 was observed in patients randomized to clarithromycin.
  • Clarithromycin for treatment of coronary artery disease is not an approved indication. Patients were treated with clarithromycin or placebo for 14 days and observed for primary outcome events (e.g., all-cause mortality or non-fatal cardiac events) for several years.1
  • A numerically higher number of primary outcome events in patients randomized to receive clarithromycin was observed with a hazard ratio of 1.06 (95% confidence interval 0.98 to 1.14).
  • However, at follow-up 10 years post-treatment, there were 866 (40%) deaths in the clarithromycin group and 815 (37%) deaths in the placebo group that represented a hazard ratio for all-cause mortality of 1.10 (95% confidence interval 1.00 to 1.21).
  • The difference in the number of deaths emerged after one year or more after the end of treatment.

The cause of the difference in all-cause mortality has not been established. Other epidemiologic studies evaluating this risk have shown variable results.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of Biaxin. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

  • Blood and Lymphatic System: Thrombocytopenia, agranulocytosis
  • Cardiac: Ventricular arrhythmia, ventricular tachycardia, torsades de pointes
  • Ear and Labyrinth: Deafness was reported chiefly in elderly women and was usually reversible.
  • Gastrointestinal: Pancreatitis acute, tongue discoloration, tooth discoloration was reported and was usually reversible with professional cleaning upon discontinuation of the drug.

There have been reports of Biaxin XL Filmtab in the stool, many of which have occurred in patients with anatomic (including ileostomy or colostomy) or functional gastrointestinal disorders with shortened GI transit times.

In several reports, tablet residues have occurred in the context of diarrhea. It is recommended that patients who experience tablet residue in the stool and no improvement in their condition should be switched to a different clarithromycin formulation (e.g. suspension) or another antibacterial drug.

  • Hepatobiliary: Hepatic failure, jaundice hepatocellular. Adverse reactions related to hepatic dysfunction have been reported with clarithromycin.
  • Infections and Infestations: Pseudomembranous colitis.
  • Immune System: Anaphylactic reactions, angioedema
  • Investigations: Prothrombin time prolonged, white blood cell count decreased, international normalized ratio increased. Abnormal urine color has been reported, associated with hepatic failure.
  • Metabolism and Nutrition: Hypoglycemia has been reported in patients taking oral hypoglycemic agents or insulin.
  • Musculoskeletal and Connective Tissue: Myopathy rhabdomyolysis was reported and in some of the reports, clarithromycin was administered concomitantly with statins, fibrates, colchicine or allopurinol.
  • Nervous System: Parosmia, anosmia, ageusia, paresthesia and convulsions
  • Psychiatric: Abnormal behavior, confusional state, depersonalization, disorientation, hallucination, depression, manic behavior, abnormal dream, psychotic disorder. These disorders usually resolve upon discontinuation of the drug.
  • Renal and Urinary: Nephritis interstitial, renal failure
  • Skin and Subcutaneous Tissue: Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS), Henoch-Schonlein purpura, acne, acute generalized exanthematous pustulosis
  • Vascular: Hemorrhage

What drugs interact with Biaxin (clarithromycin)?

  • Co-administration of Biaxin is known to inhibit CYP3A, and a drug primarily metabolized by CYP3A may be associated with elevations in drug concentrations that could increase or prolong both therapeutic and adverse effects of the concomitant drug.
  • Biaxin should be used with caution in patients receiving treatment with other drugs known to be CYP3A enzyme substrates, especially if the CYP3A substrate has a narrow safety margin (e.g., carbamazepine) and/or the substrate is extensively metabolized by this enzyme.
  • Adjust dosage when appropriate and monitor serum concentrations of drugs primarily metabolized by CYP3A closely in patients concurrently receiving clarithromycin.

  • Table 8: Clinically Significant Drug Interactions with Biaxin

Drugs That Are Affected By Biaxin
Drug(s) with Pharmacokinetics Affected by Biaxin Recommendation Comments
Antiarrhythmics: Disopyramide
Quinidine
Dofetilide
Amiodarone
Sotalol
Procainamide		 Not Recommended Disopyramide, Quinidine: There have been postmarketing reports of torsades de pointes occurring with concurrent use of clarithromycin and quinidine or disopyramide. Electrocardiograms should be monitored for QTc prolongation during coadministration of clarithromycin with these drugs.
Serum concentrations of these medications should also be monitored. There have been spontaneous or published reports of CYP3A based interactions of clarithromycin with disopyramide and quinidine.
There have been postmarketing reports of hypoglycemia with the concomitant administration of clarithromycin and disopyramide. Therefore, blood glucose levels should be monitored during concomitant administration of clarithromycin and disopyramide.
Digoxin Use With Caution Digoxin: Digoxin is a substrate for P-glycoprotein (Pgp) and clarithromycin is known to inhibit Pgp. When clarithromycin and digoxin are coadministered, inhibition of Pgp by clarithromycin may lead to increased exposure of digoxin. Elevated digoxin serum concentrations in patients receiving clarithromycin and digoxin concomitantly have been reported in postmarketing surveillance. Some patients have shown clinical signs consistent with digoxin toxicity, including potentially fatal arrhythmias. Monitoring of serum digoxin concentrations should be considered, especially for patients with digoxin concentrations in the upper therapeutic range.
Oral anticoagulants:
Oral Anticoagulants: Warfarin Use With Caution Oral anticoagulants: Spontaneous reports in the postmarketing period suggest that concomitant administration of clarithromycin and oral anticoagulants may potentiate the effects of the oral anticoagulants. Prothrombin times should be carefully monitored while patients are receiving clarithromycin and oral anticoagulants simultaneously.
Antiepileptics:
Carbamazepine Use With Caution Carbamazepine: Concomitant administration of single doses of clarithromycin and carbamazepine has been shown to result in increased plasma concentrations of carbamazepine. Blood level monitoring of carbamazepine may be considered. Increased serum concentrations of carbamazepine were observed in clinical trials with clarithromycin. There have been spontaneous or published reports of CYP3A based interactions of clarithromycin with carbamazepine.
Antifungals:
Itraconazole Use With Caution Itraconazole: Both clarithromycin and itraconazole are substrates and inhibitors of CYP3A, potentially leading to a bi-directional drug interaction when administered concomitantly (see also Itraconazole under “Drugs That Affect Biaxin” in the table below). Clarithromycin may increase the plasma concentrations of itraconazole. Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged adverse reactions.
Fluconazole No Dose Adjustment Fluconazole: See prescribing information.
Anti-Gout Agents:
Colchicine (in patients with renal or hepatic impairment) Contraindicated Colchicine: Colchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (Pgp). Clarithromycin and other macrolides are known to inhibit CYP3A and Pgp. The dose of colchicine should be reduced when co-administered with clarithromycin in patients with normal renal and hepatic function.
Colchicine (in patients with normal renal and hepatic function) Use With Caution
Antipsychotics:
Pimozide
Quetiapine		 Contraindicated Pimozide: See prescribing information.
Quetiapine: Quetiapine is a substrate for CYP3A4, which is inhibited by clarithromycin. Coadministration with clarithromycin could result in increased quetiapine exposure and possible quetiapine related toxicities. There have been postmarketing reports of somnolence, orthostatic hypotension, altered state of consciousness, neuroleptic malignant syndrome, and QT prolongation during concomitant administration. Refer to quetiapine prescribing information for recommendations on dose reduction if coadministered with CYP3A4 inhibitors such as clarithromycin.
Antispasmodics:
Tolterodine (patients deficient in CYP2D6 activity) Use With Caution Tolterodine: The primary route of metabolism for tolterodine is via CYP2D6. However, in a subset of the population devoid of CYP2D6, the identified pathway of metabolism is via CYP3A. In this population subset, inhibition of CYP3A results in significantly higher serum concentrations of tolterodine. Tolterodine 1 mg twice daily is recommended in patients deficient in CYP2D6 activity (poor metabolizers) when co-administered with clarithromycin.
Antivirals:
Atazanavir Use With Caution Atazanavir: Both clarithromycin and atazanavir are substrates and inhibitors of CYP3A, and there is evidence of a bi-directional drug interaction (see Atazanavir under “Drugs That Affect Biaxin” in the table below).
Saquinavir (in patients with decreased renal function)   Saquinavir: Both clarithromycin and saquinavir are substrates and inhibitors of CYP3A and there is evidence of a bi-directional drug interaction (see Saquinavir under “Drugs That Affect Biaxin” in the table below).
Ritonavir
Etravirine		   Ritonavir, Etravirine: (see Ritonavir and Etravirine under “Drugs That Affect Biaxin” in the table below).
Maraviroc   Maraviroc: Clarithromycin may result in increases in maraviroc exposures by inhibition of CYP3A metabolism. See Selzentry® prescribing information for dose recommendation when given with strong CYP3A inhibitors such as clarithromycin.
Boceprevir (in patients with normal renal function) Didanosine No Dose Adjustment Boceprevir: Both clarithromycin and boceprevir are substrates and inhibitors of CYP3A, potentially leading to a bi-directional drug interaction when coadministered. No dose adjustments are necessary for patients with normal renal function (see Victrelis prescribing information).
Zidovudine Zidovudine: Simultaneous oral administration of clarithromycin immediate-release tablets and zidovudine to HIV-infected adult patients may result in decreased steady-state zidovudine concentrations. Administration of clarithromycin and zidovudine should be separated by at least two hours.
The impact of co-administration of clarithromycin extended-release tablets or granules and zidovudine has not been evaluated.
Calcium Channel Blockers:
Verapamil Use With Caution Verapamil: Hypotension, bradyarrhythmias, and lactic acidosis have been observed in patients receiving concurrent verapamil.
Amlodipine
Diltiazem		 Amlodipine, Diltiazem: See prescribing information.
Nifedipine: Nifedipine is a substrate for CYP3A. Clarithromycin and other macrolides are known to inhibit CYP3A. There is potential of CYP3A-mediated interaction between nifedipine and clarithromycin. Hypotension and peripheral edema were observed when clarithromycin was taken concomitantly with nifedipine.
Nifedipine
Ergot Alkaloids:
Ergotamine Dihydroergotamine Contraindicated Ergotamine, Dihydroergotamine: Postmarketing reports indicate that coadministration of clarithromycin with ergotamine or dihydroergotamine has been associated with acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system.
Gastroprokinetic Agents:
Cisapride Contraindicated Cisapride: See prescribing information.
HMG-CoA Reductase Inhibitors:
Lovastatin
Simvastatin		 Contraindicated Lovastatin, Simvastatin, Atorvastatin, Pravastatin, Fluvastatin: See prescribing information.
Atorvastatin
Pravastatin		 Use With Caution
Fluvastatin No Dose Adjustment
Hypoglycemic Agents:
Nateglinide
Pioglitazone
Repaglinide
Rosiglitazone1
Insulin		 Use With Caution Nateglinide, Pioglitazone, Repaglinide, Rosiglitazone: See prescribing information.
Insulin: See prescribing information.
Immunosuppressants:
Cyclosporine Use With Caution Cyclosporine: There have been spontaneous or published reports of CYP3A based interactions of clarithromycin with cyclosporine.
Tacrolimus   Tacrolimus: There have been spontaneous or published reports of CYP3A based interactions of clarithromycin with tacrolimus.
Phosphodiesterase inhibitors:
Sildenafil Tadalafil Vardenafil Use With Caution Sildenafil, Tadalafil, Vardenafil: Each of these phosphodiesterase inhibitors is primarily metabolized by CYP3A, and CYP3A will be inhibited by concomitant administration of clarithromycin. Co-administration of clarithromycin with sildenafil, tadalafil, or vardenafil will result in increased exposure of these phosphodiesterase inhibitors. Co-administration of these phosphodiesterase inhibitors with clarithromycin is not recommended. Increased systemic exposure of these drugs may occur with clarithromycin; reduction of dosage for phosphodiesterase inhibitors should be considered (see their respective prescribing information).
Proton Pump Inhibitors:
Omeprazole No Dose Adjustment Omeprazole: The mean 24-hour gastric pH value was 5.2 when omeprazole was administered alone and 5.7 when coadministered with clarithromycin as a result of increased omeprazole exposures (see also Omeprazole under “Drugs That Affect Biaxin” in the table below).
Xanthine Derivatives:
Theophylline Use With Caution Theophylline: Clarithromycin use in patients who are receiving theophylline may be associated with an increase of serum theophylline concentrations [see Pharmacokinetics]. Monitoring of serum theophylline concentrations should be considered for patients receiving high doses of theophylline or with baseline concentrations in the upper therapeutic range.
Triazolobenzodiazepines and Other Related Benzodiazepines:
Midazolam Use With Caution Midazolam: When oral midazolam is coadministered with clarithromycin, dose adjustments may be necessary and possible prolongation and intensity of effect should be anticipated.
Alprazolam
Triazolam		 Triazolam, Alprazolam: Caution and appropriate dose adjustments should be considered when triazolam or alprazolam is co-administered with clarithromycin. There have been postmarketing reports of drug interactions and central nervous system (CNS) effects (e.g., somnolence and confusion) with the concomitant use of clarithromycin and triazolam. Monitoring the patient for increased CNS pharmacological effects is suggested.
In postmarketing experience, erythromycin has been reported to decrease the clearance of triazolam and midazolam, and thus, may increase the pharmacologic effect of these benzodiazepines.
Temazepam
Nitrazepam
Lorazepam		 No Dose Adjustment Temazepam, Nitrazepam, Lorazepam: For benzodiazepines which are not metabolized by CYP3A (e.g., temazepam, nitrazepam, lorazepam), a clinically important interaction with clarithromycin is unlikely.
Cytochrome P450 Inducers:
Rifabutin Use With Caution Rifabutin: Concomitant administration of rifabutin and clarithromycin resulted in an increase in rifabutin, and decrease in clarithromycin serum levels together with an increased risk of uveitis (see Rifabutin under “Drugs That Affect Biaxin” in the table below).
Other Drugs Metabolized by CYP3A:
Alfentanil
Bromocriptine
Cilostazol
Methylprednisole
Vinblastine
Phenobarbital
St. John’s Wort		 Use With Caution There have been spontaneous or published reports of CYP3A based interactions of clarithromycin with alfentanil, methylprednisolone, cilostazol, bromocriptine, vinblastine, phenobarbital, and St. John’s Wort.
Other Drugs Metabolized by CYP450 Isoforms Other than CYP3A:
Hexobarbital
Phenytoin
Valproate		 Use With Caution There have been postmarketing reports of interactions of clarithromycin with drugs not thought to be metabolized by CYP3A, including hexobarbital, phenytoin, and valproate.
Drugs that Affect Biaxin
Drug(s) that Affect the Pharmacokinetics of Biaxin Recommendation Comments
Antifungals:
Itraconazole Use With Caution Itraconazole: Itraconazole may increase the plasma concentrations of clarithromycin. Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged adverse reactions (see also Itraconazole under “Drugs That Are Affected By Biaxin” in the table above).
Antivirals:
Atazanavir Use With Caution Atazanavir: When clarithromycin is co-administered with atazanavir, the dose of clarithromycin should be decreased by 50%.
Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is coadministered with atazanavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium complex. Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors.
Ritonavir (in patients with decreased renal function) Ritonavir: Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with ritonavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium.
Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors.
Saquinavir (in patients with decreased renal function) Saquinavir: When saquinavir is co-administered with ritonavir, consideration should be given to the potential effects of ritonavir on clarithromycin (refer to ritonavir above).
Etravirine Etravirine: Clarithromycin exposure was decreased by etravirine; however, concentrations of the active metabolite, 14-OH-clarithromycin, were increased. Because 14-OH-clarithromycin has reduced activity against Mycobacterium avium complex (MAC), overall activity against this pathogen may be altered; therefore alternatives to clarithromycin should be considered for the treatment of MAC.
Saquinavir (in patients with normal renal function) No Dose Adjustment  
Ritonavir (in patients with normal renal function)    
Proton Pump Inhibitors:
Omeprazole Use With Caution Omeprazole: Clarithromycin concentrations in the gastric tissue and mucus were also increased by concomitant administration of omeprazole.
Miscellaneous Cytochrome P450 Inducers:
Efavirenz
Nevirapine
Rifampicin
Rifabutin
Rifapentine		 Use With Caution Inducers of CYP3A enzymes, such as efavirenz, nevirapine, rifampicin, rifabutin, and rifapentine will increase the metabolism of clarithromycin, thus decreasing plasma concentrations of clarithromycin, while increasing those of 14-OH-clarithromycin. Since the microbiological activities of clarithromycin and 14-OH-clarithromycin are different for different bacteria, the intended therapeutic effect could be impaired during concomitant administration of clarithromycin and enzyme inducers. Alternative antibacterial treatment should be considered when treating patients receiving inducers of CYP3A. There have been spontaneous or published reports of CYP3A based interactions of clarithromycin with rifabutin (see Rifabutin under “Drugs That Are Affected By Biaxin” in the table above).

Summary

Biaxin (clarithromycin) is a macrolide antibiotic used to treat susceptible bacteria causing the following infections: middle ear, tonsillitis, throat infections, laryngitis, bronchitis, pneumonia, and skin infections. Common side effects of Biaxin include nausea, diarrhea, abnormal taste, indigestion/heartburn, abdominal pain and headache. There are no adequate studies of Biaxin in pregnant women. Biaxin is excreted in breast milk. Consult your doctor before breastfeeding.

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