Clarithromycin (Biaxin): Uses, Warnings, and More

What is clarithromycin?

Clarithromycin is an active ingredient used to treat certain bacterial infections. The content provided for this page identifies it as clarithromycin citrate.

In the United States, common brand names include Biaxin and Biaxin XL.

How clarithromycin works

Clarithromycin works by interfering with protein synthesis in sensitive bacteria. It binds to the 50S ribosomal subunit, which helps stop bacterial growth.

What clarithromycin is used for

The original content lists clarithromycin for several bacterial infections. These include:

• Pharyngitis and tonsillitis
• Sinusitis
• Chronic bronchitis and acute exacerbations of chronic bronchitis
• Bacterial pneumonia
• Mild to moderate skin and soft tissue infections
• Folliculitis, cellulitis, and erysipelas
• Some infections caused by M. avium, M. intracellulare, M. chelonae, M. fortuitum, and M. kansaii
• Gastric or duodenal ulcer associated with H. pylori, together with appropriate anti-ulcer treatment
• Prevention of disseminated infection by M. avium complex in high-risk HIV patients

Some uses are listed for adults, adolescents, or children in the original content. The exact indication depends on the formulation and the clinical situation.

Available forms and administration

The original content mentions oral and intravenous forms.

Oral forms

• Tablets
• Extended-release tablets
• Granules for suspension

Granules for suspension must be reconstituted before use.

Intravenous use

IV clarithromycin is administered by infusion in a large proximal vein. The original content states it should be infused over 60 minutes and not given as a bolus or intramuscular injection.

Dosage information from the original content

The dose depends on the formulation, age, infection, and kidney function. The original content includes the following examples:

Because dosing varies by product and condition, readers should verify the exact regimen in the official leaflet or with a healthcare professional.

Contraindications listed in the original content

• Hypersensitivity to macrolides
• Use with certain medicines that may increase the risk of QT prolongation or severe arrhythmias
• Hypokalemia
• Severe liver failure combined with renal failure
• Congenital or acquired QT interval prolongation
• Modified-release tablets in creatinine clearance below 30 mL/minute

Warnings and precautions

• Use caution in pregnancy; the original content says risk and benefit should be assessed.
• Use caution in older adults.
• Use caution in moderate to severe kidney failure and liver failure.
• Stop treatment and seek medical advice if signs of liver disease appear, such as anorexia, jaundice, dark urine, itching, or abdominal tenderness.
• There is a risk of C. difficile-associated colitis, superinfection, and worsening of myasthenia gravis.
• Monitor for possible hearing-related effects during prolonged treatment, especially in M. avium infection.
• Use caution with medicines that may prolong the QT interval or affect blood sugar, bleeding, or heart rhythm.
• Stop treatment if hypersensitivity reactions occur, including severe skin reactions.

Kidney and liver considerations

The original content notes that clarithromycin is mainly excreted by the liver, so caution is needed in liver disease. It also states that severe liver failure combined with renal failure is a contraindication.

For renal impairment, the content highlights dose reduction when creatinine clearance is below 30 mL/min. The exact adjustment depends on the formulation.

Important drug interactions

Clarithromycin inhibits CYP3A4, so it can interact with many medicines. The original content lists interactions with:

• Some antiarrhythmics and other QT-prolonging medicines
• Statins such as lovastatin and simvastatin
• Colchicine
• Ergot derivatives
• Digoxin
• Cyclosporine, tacrolimus, and sirolimus
• Phenytoin, carbamazepine, valproate, and theophylline
• Alprazolam and some other sedatives
• Some HIV medicines and rifamycins
• Calcium channel blockers such as verapamil and diltiazem
• Oral anticoagulants

If you take prescription medicines, over-the-counter products, or herbal supplements, the official leaflet and a pharmacist can help check for interactions.

Pregnancy and breastfeeding

The original content says the safety of clarithromycin in pregnancy has not been established and that risk and benefit should be considered.

It also states that clarithromycin is excreted in breast milk and should not be used during lactation.

Effects on driving and using machines

No specific data were provided in the original content. It advises considering possible effects such as dizziness, vertigo, confusion, or disorientation before driving or using machines.

Possible side effects listed in the original content

• Headache
• Altered taste or dysgeusia
• Insomnia
• Hearing loss, which may be reversible after stopping treatment
• Tinnitus
• Dyspepsia, nausea, and abdominal pain
• Mild skin rash
• Changes in liver function tests
• With IV use: vasodilation, phlebitis, pain, and inflammation at the injection site

The original content also mentions serious cardiovascular outcomes among reported adverse reactions. Any new chest pain, fainting, palpitations, or severe reaction should be assessed urgently.

What to verify in the official leaflet

Because clarithromycin products can differ by formulation, it is useful to confirm:

• The exact indication for the specific product
• Whether the tablet is standard release or modified release
• Age limits for the formulation
• Kidney dose adjustments
• Interaction warnings for your current medicines
• Pregnancy and breastfeeding guidance

Safety reminder

Frequently asked questions

Sources and official references

The original content cites FDA and U.S. drug information resources. For verification, readers can review the official medication guide and product labeling.