What You Need to Know About Clindamycin Side Effects

Clindamycin is a powerful antibiotic — and like all antibiotics, it comes with side effects. Most are mild and go away on their own. But some are serious enough that you need to know the warning signs before you start treatment.

This guide covers the common side effects you'll probably experience, the serious ones you need to watch for, and exactly when to call your doctor.

What Is Clindamycin?

Clindamycin is a lincosamide antibiotic that fights bacterial infections. It's available under brand names like Cleocin, ClindaMax, and Evoclin, and comes in oral capsules, topical formulations (gel, lotion, foam), injectable solutions, and vaginal preparations.

Doctors prescribe it for skin and soft tissue infections, respiratory tract infections, bone and joint infections, dental infections, acne, and bacterial vaginosis. For a full overview, see our guide: What Is Clindamycin?

Common Side Effects

These side effects affect a significant number of people taking Clindamycin. They're usually mild and manageable:

Gastrointestinal Effects (Most Common)

• Diarrhea — This is the most frequent side effect, affecting up to 20% of patients taking oral Clindamycin. The antibiotic disrupts your gut bacteria, which can cause loose or watery stools.
• Nausea — Stomach discomfort is common, especially when starting treatment.
• Vomiting — Less common than nausea but still reported.
• Abdominal pain or cramping — Mild belly discomfort during treatment.

Other Common Side Effects

• Metallic taste — Some people notice an unpleasant metallic taste in their mouth, particularly with oral formulations.
• Rash — A mild skin rash can develop during treatment.
• Vaginal irritation — For those using vaginal Clindamycin cream or suppositories.
• Skin irritation — Dryness, peeling, or burning at the application site with topical Clindamycin (gel, lotion, foam).

Important: Mild diarrhea during antibiotic treatment is common and usually not dangerous. However, Clindamycin carries a specific warning about a more serious form of diarrhea — read the next section carefully.

Serious Side Effects: When to Call Your Doctor Immediately

Clindamycin has an FDA Boxed Warning — the most serious type of drug safety warning — for a condition called Clostridioides difficile-associated diarrhea (CDAD). Here's what to watch for:

C. difficile-Associated Diarrhea (CDAD)

This is the most important risk to understand. Clindamycin can kill the beneficial bacteria in your gut, allowing a dangerous bacterium called C. difficile to overgrow. This can cause:

• Severe, watery diarrhea (10+ times per day)
• Bloody or mucus-filled stools
• Fever
• Severe abdominal cramping and tenderness
• Dehydration

Call your doctor immediately if you develop severe diarrhea, especially with blood or mucus. CDAD can occur during treatment or even weeks after you finish your course of Clindamycin. Do not take anti-diarrheal medications (like Imodium) without asking your doctor first — they can make CDAD worse.

Severe Allergic Reactions (Anaphylaxis)

Though rare, anaphylaxis can occur. Seek emergency medical help if you experience:

• Difficulty breathing or swallowing
• Swelling of face, lips, tongue, or throat
• Hives or widespread rash
• Rapid heartbeat
• Dizziness or fainting

Severe Skin Reactions

• Stevens-Johnson syndrome (SJS) — Painful blistering of the skin and mucous membranes
• DRESS syndrome — Drug Reaction with Eosinophilia and Systemic Symptoms: fever, rash, swollen lymph nodes, and organ involvement

These are medical emergencies. Go to the ER immediately.

Liver Problems (Hepatotoxicity)

Signs include:

• Yellowing of skin or eyes (jaundice)
• Dark urine
• Unusual fatigue
• Upper right abdominal pain

Blood Disorders (Agranulocytosis)

Rarely, Clindamycin can affect blood cell production. Watch for:

• Unexplained fever or chills
• Persistent sore throat
• Unusual bruising or bleeding

Side Effects in Specific Populations

Pregnant Women

Clindamycin is Pregnancy Category B, meaning animal studies haven't shown harm, but there are no adequate human studies. It's generally considered safe when the benefit outweighs the risk. Your OB/GYN should make this call.

Breastfeeding Mothers

Clindamycin is excreted in breast milk. While it's sometimes used during breastfeeding, watch your infant for diarrhea, rash, or thrush. Discuss the risks with your doctor.

Children

Clindamycin is approved for use in children. The oral solution (75 mg/5 mL) is available for pediatric dosing. GI side effects (especially diarrhea) are the most common concern.

Older Adults

Older adults are at higher risk for C. difficile infection. If you're over 65, your doctor may monitor you more closely or consider alternative antibiotics when possible.

People With Liver Disease

Clindamycin is metabolized by the liver. If you have severe hepatic impairment, your doctor may adjust your dose or choose a different antibiotic.

How to Manage Common Side Effects

Here are practical tips to reduce discomfort while taking Clindamycin:

For Diarrhea

• Take a probiotic — Probiotics containing Saccharomyces boulardii or Lactobacillus strains may help reduce antibiotic-associated diarrhea. Take them at least 2 hours apart from your Clindamycin dose.
• Stay hydrated — Drink plenty of water and electrolyte drinks.
• Eat bland foods — Rice, bananas, toast, and applesauce can help settle your stomach.
• Don't stop your medication early — Unless your doctor tells you to. Mild diarrhea usually isn't a reason to stop treatment.

For Nausea

• Take your capsules with a full glass of water
• Take doses with food if nausea is bothersome (Clindamycin can be taken with or without food)
• Avoid lying down immediately after taking your dose

For Metallic Taste

• Chew sugar-free gum or mints
• Rinse your mouth after taking your dose
• This side effect goes away when you finish treatment

For Topical Irritation

• Apply a thin layer only — more product doesn't mean better results
• Use a gentle, fragrance-free moisturizer
• Avoid combining with other harsh topical products (benzoyl peroxide, retinoids) unless directed by your dermatologist

When to Call Your Doctor: Quick Reference

Call immediately if you experience:

• Severe or bloody diarrhea
• Diarrhea with fever and abdominal cramping
• Signs of allergic reaction (swelling, hives, difficulty breathing)
• Blistering or peeling skin
• Yellowing of eyes or skin
• Unexplained fever, sore throat, or unusual bruising

Mention at your next visit:

• Mild diarrhea that's manageable but persistent
• Ongoing nausea or stomach discomfort
• Rash that doesn't worsen
• Metallic taste

Final Thoughts

Most people tolerate Clindamycin well. Diarrhea is the most common complaint, and for most patients it's mild and temporary. But the risk of C. difficile infection is real — it's why Clindamycin carries a boxed warning and why doctors reserve it for infections where less toxic antibiotics aren't appropriate.

Know the warning signs, don't hesitate to call your doctor if something feels wrong, and complete your full course of treatment unless told otherwise.

Need to fill your prescription? Medfinder can help you find Clindamycin in stock at a pharmacy near you.