Amoxicillin Vs. Clindamycin: Drug Comparison

Amoxicillin is a broad-spectrum antibiotic in the penicillin class that treats bacterial infections by inhibiting the formation of bacterial cell walls, leading to their destruction. FDA-approved indications include treating infections such as pneumonia, ear infections, sinusitis, strep throat, and urinary tract infections. Off-label uses may include treatment of Lyme disease or prevention of bacterial endocarditis in certain patients. Amoxicillin is available in various forms, including capsules, tablets, chewable tablets, and oral suspensions. Common side effects include nausea, diarrhea, and skin rash. Amoxicillin may interact with blood thinners like warfarin. Caution is advised in patients with penicillin allergies.

Clindamycin is an antibiotic used to treat bacterial infections by inhibiting bacterial protein synthesis, effectively stopping bacterial growth. Its FDA-approved indications include the treatment of serious infections such as respiratory tract infections, skin and soft tissue infections, and infections caused by susceptible anaerobic bacteria. Off label, clindamycin may be used for treating acne, bacterial vaginosis, or certain types of bone and joint infections. It is available in various forms, including oral capsules, topical solutions, and intravenous (IV) injections. Common side effects include nausea, abdominal pain, diarrhea, and rash. Clindamycin carries a boxed warning for the risk of severe and potentially life-threatening Clostridioides difficile-associated diarrhea (C. diff), a serious gastrointestinal complication.

Penicillin-class antibacterial

Lincomycin antibiotic

Amoxicillin is indicated for treatment of infections due to susceptible strains of designated microorganisms:

• Infections of the ear, nose, throat, genitourinary tract, skin and skin structure, and lower respiratory tract

• In combination for treatment of H. pylori infection and duodenal ulcer disease

Clindamycin is indicated in:

• The treatment of serious infections caused by susceptible anaerobic bacteria

• Typically taken orally twice or three times daily

• Comes in 250 mg and 300 mg capsules

• Typically taken orally four times daily

• Comes in 75 mg, 150 mg, and 300 mg capsules

The most common adverse reactions (>1%) observed in clinical trials of amoxicillin capsules, were:

• Diarrhea

• Rash

• Vomiting

• Nausea

Adverse reactions have been reported in the following systems:

• Infections and infestations

• Gastrointestinal

• Hypersensitivity reactions

• Skin and mucous membranes

• Liver

• Renal

• Hematopoietic

• Immune system

• Musculoskeletal

• History of a serious hypersensitivity reaction (e.g., anaphylaxis or Stevens-Johnson syndrome) to amoxicillin or to other beta-lactams (e.g., penicillins or cephalosporins)

• Drug interactions: Probenicid, oral anticoagulants, allopurinol, oral contraceptives

• Hypersensitivity to preparations containing clindamycin or lincomycin

• Drug interactions: neuromuscular blocking agents, inhibitors and inducers of CYP3A4 and CYP3A5

• Anaphylactic reactions

• Drug-induced enterocolitis syndrome

• Clostridium difficile-associated diarrhea (ranging from mild diarrhea to fatal colitis)

• Clostridioides difficile-associated diarrhea

• Anaphylactic and severe hypersensitivity reactions

• Nephrotoxicity

• Pregnancy: Clindamycin should be used during the first trimester of pregnancy only if clearly needed

• Breastfeeding: Clindamycin has the potential to cause adverse effects on the breast-fed infant's gastrointestinal flora

WARNING

Clostridioides difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including clindamycin HCl and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon, leading to overgrowth of C. difficile.

Because clindamycin HCl therapy has been associated with severe colitis which may end fatally, it should be reserved for serious infections where less toxic antimicrobial agents are inappropriate, as described in the INDICATIONS AND USAGE section. It should not be used in patients with nonbacterial infections such as most upper respiratory tract infections.

C. difficile produces toxins A and B, which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents.

If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.

*This information is from the amoxicillin label used by Micro Labs Limited. See the Full Prescribing Information for more complete information. This information may not be accurate for all medications that include the active ingredient amoxicillin.

*This information is from the clindamycin hydrochloride label used by Chartwell RX, LLC. See the Full Prescribing Information for more complete information. Clindamycin may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient clindamycin.