Metronidazole vs. Clindamycin
See how Metronidazole and Clindamycin compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Metronidazole is a nitroimidazole used mainly for trichomoniasis, bacterial vaginosis, and anaerobic or parasitic infections, while clindamycin is a lincosamide used for a broader range of anaerobic and gram-positive bacterial infections.
Both carry boxed warnings, but for different reasons: metronidazole for potential carcinogenicity shown in animal studies, and clindamycin for severe C. difficile-associated diarrhea and colitis.
Metronidazole is typically taken for a short, defined course, while clindamycin dosing varies more widely depending on infection severity and route.
Metronidazole vs. Clindamycin Drug Summary
Metronidazole
Metronidazole is a nitroimidazole antimicrobial used to treat trichomoniasis, bacterial vaginosis, amebiasis, and various anaerobic bacterial infections. It comes as an oral tablet or capsule, and also as IV, topical, and vaginal formulations, usually taken for a short defined course.
Clindamycin
Clindamycin is a lincosamide antibacterial used for serious infections caused by anaerobic bacteria as well as certain streptococci, staphylococci, and pneumococci. It is available as an oral capsule, IV or IM injection, and topical or vaginal formulations, with dosing that varies by infection type and severity.
Metronidazole vs. Clindamycin Side Effects
Metronidazole
Clindamycin
Metronidazole vs. Clindamycin Dosage
Metronidazole
Clindamycin
| STAGE | DOSE | WHEN |
| Starting dose | 250 mg three times daily | Days 1-7 |
| Maximum dose | 2 g single or divided dose | Day 1 |
| Dose changes | 1 increase | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 150 mg every 6 hours | At the start |
| Maximum dose | up to 4800 mg/day IV | If needed |
| Dose changes | 6 increases | As tolerated |
Metronidazole
| STAGE | DOSE | WHEN |
| Starting dose | 250 mg three times daily | Days 1-7 |
| Maximum dose | 2 g single or divided dose | Day 1 |
| Dose changes | 1 increase | As tolerated |
Clindamycin
| STAGE | DOSE | WHEN |
| Starting dose | 150 mg every 6 hours | At the start |
| Maximum dose | up to 4800 mg/day IV | If needed |
| Dose changes | 6 increases | As tolerated |
Metronidazole vs. Clindamycin Indications
Metronidazole
Metronidazole is FDA-approved for trichomoniasis, bacterial vaginosis, amebiasis, and anaerobic bacterial infections including intra-abdominal infections. A topical form is approved for rosacea. It is also used off-label for H. pylori eradication and C. difficile infection.
Trichomoniasis (symptomatic and asymptomatic)
Bacterial vaginosis
Amebiasis
Intra-abdominal infections including peritonitis and liver abscess
Rosacea (topical form)
Clindamycin
Clindamycin is FDA-approved for serious infections caused by anaerobic bacteria as well as susceptible streptococci, pneumococci, and staphylococci. It covers lower respiratory, skin, gynecological, intra-abdominal, and bone or joint infections. Topical forms are approved for acne, and a vaginal form for bacterial vaginosis.
Serious anaerobic bacterial infections
Skin and skin structure infections
Lower respiratory tract infections
Bone and joint infections
Acne vulgaris (topical form)
Metronidazole vs. Clindamycin Pros and Cons
Metronidazole
Metronidazole is a well-established, low-cost option that remains first-line for trichomoniasis and bacterial vaginosis. It carries a boxed warning based on animal carcinogenicity data and requires strict avoidance of alcohol during treatment.
Pros
First-line choice for trichomoniasis and bacterial vaginosis
Long track record of use since 1963
Effective off-label for C. difficile and H. pylori regimens
Available in oral, IV, topical, and vaginal forms
Cons
Boxed warning for carcinogenicity shown in animal studies
Causes a disulfiram-like reaction if combined with alcohol
Contraindicated with disulfiram or in Cockayne syndrome
Risk of seizures, peripheral neuropathy, and metallic taste
Clindamycin
Clindamycin covers a broader range of gram-positive and anaerobic bacteria, making it a common alternative for patients with penicillin allergies. It carries a boxed warning for C. difficile-associated diarrhea and colitis, which can be severe.
Pros
Preferred alternative for penicillin-allergic patients
Covers streptococci, staphylococci, and pneumococci, not just anaerobes
Useful for bone, joint, and lower respiratory infections
Available in oral, IV/IM, topical, and vaginal forms, including acne treatment
Cons
Boxed warning for C. difficile-associated diarrhea and colitis
Oral capsules can cause esophagitis if not taken with enough fluid
Should not be combined with erythromycin due to antagonism
Reserved for serious infections due to risk profile
Common Symptoms and Related Diseases You Can Explore
Explore a range of common symptoms the Doctronic Symptom Checker can help you understand.