Biaxin (clarithromycin) is generally well-tolerated in pediatric patients aged 6 months and older, with gastrointestinal effects being most common. Taste disturbance (dysgeusia) affects up to 16% of patients, making it one of the most frequent side effects. QT prolongation is a serious concern requiring cardiac monitoring in high-risk patients. While hepatotoxicity is rare, it can be severe when it occurs, particularly with higher doses. Safety and efficacy are not established in children under 6 months for bacterial infections.
The most common side effects include diarrhea (3%), nausea (3%), abdominal pain (3%), and vomiting (6%). C. difficile-associated diarrhea can occur during treatment or up to 2 months after completion, requiring immediate medical attention. Generally mild and self-limiting with standard therapeutic doses. Management: Give with food to reduce stomach upset, maintain hydration, avoid anti-diarrheal medications for severe cases. Monitoring: Watch for severe, bloody, or persistent diarrhea; report cramping, fever, or signs of dehydration immediately.
Metallic or abnormal taste occurs in up to 16% of patients, making it one of the most frequent side effects. Can significantly impact appetite and nutrition, especially in children. Usually reversible after treatment completion but may persist for days to weeks. Management: Encourage varied flavors, use sugar-free gum or mints, maintain good oral hygiene, ensure adequate nutrition despite taste changes. Monitoring: Report persistent taste changes lasting >2 weeks after completion or significant impact on eating.
Clarithromycin can cause dangerous heart rhythm abnormalities including QT prolongation and torsade de pointes. Risk is higher in patients with existing heart conditions, electrolyte imbalances, or concurrent QT-prolonging medications. Can be life-threatening and requires immediate intervention. Management: Avoid in patients with known QT prolongation, monitor electrolytes, obtain baseline and follow-up ECGs in high-risk patients. Monitoring: Watch for palpitations, chest pain, fainting, or unusual fatigue; seek emergency care for cardiac symptoms.
Rare but potentially severe liver injury can occur, typically presenting as cholestatic hepatitis within one week of treatment initiation. More common with higher doses (1-2 g/day) and in patients with underlying liver disease. Fatal cases have been reported, particularly in elderly patients with comorbidities. Management: Monitor liver function tests in high-risk patients, discontinue immediately if liver injury suspected. Monitoring: Watch for jaundice, dark urine, right upper quadrant pain, unusual fatigue, or pale stools.
Clarithromycin is a potent CYP3A4 inhibitor, leading to significant drug interactions with many commonly prescribed medications. Notable interactions include statins (muscle toxicity), colchicine (toxicity), and various cardiac medications. Can affect levels of other antibiotics and immunosuppressants. Management: Review all medications before prescribing, avoid contraindicated combinations, monitor for signs of drug toxicity. Monitoring: Watch for unusual symptoms when starting clarithromycin with other medications, report muscle pain, weakness, or other new symptoms.
Biaxin adverse effects in pediatric patients include gastrointestinal symptoms (3-6% incidence), taste disturbance (up to 16%), and rare but serious QT prolongation and hepatotoxicity. The medication has extensive drug interactions due to CYP3A4 inhibition. Most side effects are mild and reversible, but cardiac and hepatic complications require immediate attention.
4 documented effects
Usually resolves within days of treatment completion
Maintain hydration; give with food; avoid anti-diarrheal medications if severe; probiotics may help
Report severe, bloody, or persistent diarrhea >3 days; watch for signs of C. difficile infection
Self-limited; resolves between doses
Take with food; ensure adequate fluid intake; consider dose timing adjustments
Report persistent vomiting preventing oral intake or signs of dehydration
Usually temporary and self-limiting
Take with food; maintain regular meal schedule; avoid spicy foods
Report severe or persistent abdominal pain, especially with fever
Requires specific antibiotic treatment; can be prolonged
Discontinue clarithromycin immediately; specific antibiotic therapy; supportive care
Watch for severe, watery, bloody diarrhea with fever, cramping, or abdominal pain
3 documented effects
Usually resolves days to weeks after completion; may persist longer
Encourage varied flavors; sugar-free gum/mints; maintain oral hygiene; ensure adequate nutrition
Monitor food intake in children; report persistent taste changes >2 weeks after completion
Usually resolves with continued therapy
Ensure adequate rest and hydration; consider acetaminophen if needed
Report persistent or severe headaches, especially with fever or neck stiffness
Usually temporary
Avoid activities requiring alertness; ensure proper hydration; consider dose timing
Report persistent dizziness or balance problems
2 documented effects
Usually reversible after discontinuation
Monitor QTc interval; avoid in patients with known QT prolongation; maintain electrolyte balance
Watch for palpitations, chest pain, fainting, or unusual fatigue; obtain ECG if risk factors
Immediate intervention required; potentially fatal
Emergency cardiac care; discontinue immediately; correct electrolytes; consider defibrillation
Continuous cardiac monitoring for high-risk patients; immediate care for cardiac symptoms
2 documented effects
Variable; most recover but some develop chronic injury
Discontinue immediately if liver injury suspected; supportive care; monitor liver function
Watch for jaundice, dark urine, right upper quadrant pain, unusual fatigue, pale stools
Life-threatening emergency requiring intensive care
Emergency medical care; discontinue immediately; supportive care; consider liver transplant
Monitor liver function tests in high-risk patients; immediate care for liver injury signs
1 documented effect
Usually resolves after discontinuation
Discontinue if severe; antihistamines for mild reactions; topical steroids per provider guidance
Watch for widespread rash, fever, blistering, or signs of severe allergic reaction
Age under 6 months (safety not established for bacterial infections)
Pre-existing cardiac conditions or family history of QT prolongation
Electrolyte imbalances (hypokalemia, hypomagnesemia)
Hepatic impairment or history of liver disease
Concurrent use of QT-prolonging medications
Renal impairment (dose adjustment required)
Give with food to reduce GI upset; maintain good oral hygiene for taste disturbances; review all medications for interactions; monitor electrolytes if cardiac risk factors; avoid in patients under 6 months; complete full course even if symptoms improve; use sugar-free products to help with metallic taste
📞 Call your pediatrician immediately if you notice any of these symptoms:
Signs of liver injury (jaundice, dark urine, right upper quadrant pain, unusual fatigue)
Cardiac symptoms (palpitations, chest pain, fainting, irregular heartbeat)
Severe or bloody diarrhea with fever or cramping
Signs of severe allergic reaction (widespread rash, difficulty breathing, swelling)
Severe muscle pain or weakness (if taking interacting medications)
Persistent taste changes affecting nutrition significantly
Signs of drug toxicity from interactions (unusual symptoms with other medications)
| Effect | Biaxin | Azithromycin |
|---|---|---|
| Taste disturbance | Up to 16% (most common) | Less common |
| QT prolongation | Documented risk | Lower but documented risk |
| Drug interactions | Extensive (CYP3A4 inhibitor) | Fewer interactions |
Contraindicated; increased risk of severe muscle problems including rhabdomyolysis
Contraindicated in patients with kidney or liver disease; increased colchicine toxicity
Contraindicated; additive risk of QT prolongation and torsade de pointes
Contraindicated; increased risk of ergot toxicity and vasospasm
Enhanced anticoagulant effect; monitor INR closely and adjust warfarin dose
Biaxin is not approved for babies under 6 months old. For older infants, watch closely for diarrhea, vomiting, or changes in feeding. The medicine may cause a metallic taste that makes your baby fussy during feedings.
Your toddler may complain about a 'yucky' or 'metal' taste in their mouth - this happens to many children taking Biaxin. They might also have an upset tummy or loose stools. These usually get better after finishing the medicine.
Biaxin can make food taste metallic or weird - like having pennies in your mouth. Your child might also feel queasy or have diarrhea. Let them know these side effects are temporary and will go away after treatment.
This antibiotic commonly causes a metallic taste that can last for weeks. It also has many drug interactions, so don't take any other medications without checking first. Report any heart palpitations, severe stomach pain, or yellowing of skin immediately.
A: The metallic taste from Biaxin affects up to 16% of children and can significantly impact appetite. Try offering cold foods, citrus flavors, or sugar-free mints. Ensure they stay hydrated even if eating less. The taste will return to normal after stopping the medicine, though it may take a few weeks.
When to validate: Contact us if your child loses weight, shows signs of dehydration, or refuses all food for more than 24 hours.
A: Biaxin interacts with many medications because it affects how the liver processes drugs. This includes common medications like some allergy medicines, stomach acid reducers, and even some vitamins. Always check with us or a pharmacist before giving any other medication, including over-the-counter drugs.
When to validate: Call immediately if your child is taking any heart medications, has muscle pain while on cholesterol medicine, or develops new symptoms after starting another medication.
A: While rare, Biaxin can affect heart rhythm, especially in children with existing heart conditions or low potassium/magnesium levels. Most children have no cardiac issues, but it's important to watch for warning signs.
When to validate: Seek immediate care if your child has chest pain, racing heartbeat, dizziness, fainting, or says their heart feels 'funny' or 'fluttery'.
A: Biaxin can cause a serious intestinal infection called C. difficile that may occur even 2 months after finishing treatment. This is different from regular antibiotic-related diarrhea and requires specific treatment.
When to validate: Contact us immediately for severe, watery, or bloody diarrhea, especially with fever, stomach cramps, or if it persists more than 3 days after completing Biaxin.
Evidence-based clinical assessment framework for Biaxin adverse effects with focus on QT prolongation, hepatotoxicity, and drug interactions.
Parent and clinician concerns about Biaxin