Clindamycin is an FDA-approved for the treatment of septicemia, intra-abdominal infections, lower respiratory infections, gynecological infections, bone, and joint infections, and skin and skin structure infections. Clindamycin is also used in the treatment of streptococcal pharyngitis, acne vulgaris, bacterial vaginosis, and severe pelvic inflammatory disease. Although not a first-line treatment, Infectious Diseases Society of America (IDSA) has published guidelines for using intravenous (IV) clindamycin for the inpatient treatment of community-acquired pneumonia and aspiration pneumonia. Dentists will use clindamycin for prophylactic coverage against endocarditis. Anesthesiologists and surgeons will often administer clindamycin per American Society of Health-System Pharmacists (ASHP) and IDSA guidelines as prophylaxis in the operating room. Gynecologists use clindamycin in combination with gentamycin +/- ampicillin for covering their patients with endometritis. It can also be an alternative to metronidazole for treating Gardnerella vaginosis, which presents with gray, fishy vaginal odor with clue cells on wet prep. 

Additionally, clindamycin can be used to treat babesiosis, anthrax, and malaria. Clindamycin is also commonly used in skin and soft tissue infections that are uncomplicated. Clindamycin is used in soft tissue infections when due to its efficacy against MRSA. Clindamycin is also a choice for outpatient treatment because of its cost, availability, and effectiveness against methicillin-resistant Staphylococcus aureus.

Clindamycin prevents peptide bond formation, thereby inhibiting protein synthesis by reversibly binding to 50S ribosomal subunits. Depending on the organism, infection site, and drug concentration, clindamycin may be a bacteriostatic or bactericidal antibiotic. When taken orally, absorption cannot take place until clindamycin palmitate becomes hydrolyzed in the gastrointestinal (GI) tract. It then distributes across the body in tissue and other regions containing blood. Clindamycin cannot efficiently penetrate meninges very well and is therefore not an antibiotic of choice for infections of the cerebrospinal fluid (CSF). As it travels through the bloodstream, clindamycin is primarily bound to protein. Clindamycin is primarily metabolized in the liver by CYP 3A4 (major) and CYP 3A5, which oxidize the antibiotic into clindamycin sulfoxide (primary metabolite) and N-desmethyl clindamycin respectively. When administered orally, the antibiotic peaks within 60 minutes. When given intramuscularly (IM), the drug achieves peak concentrations in 1 to 3 hours. The half-life of clindamycin is approximately 3 hours in adults and approximately 2.5 hours in children, at which point it is excreted in the urine (major) and feces (minor) as active and inactive metabolites.[1][2][3][4]

Clindamycin can be administered into the body by multiple routes. It is available topically as a foam, gel, lotion, or solution for the treatment of acne vulgaris. A thin film needs to be applied twice a day. For the treatment of bacterial vaginosis, it is available in cream and suppository for intravaginal administration. Systemic infections can be treated orally with a capsule (75 mg, 150 mg, 300 mg) or in solution (75 mg/5 mL). It is also available as an intramuscular injection (9 g/60 mL, 300 mg/2 mL, 600 mg/4 mL, 900 mg/6 mL). Intravenous formulations are available as follows: clindamycin phosphate (300 mg/2 mL, 600 mg/4 mL, 900 mg/6 mL), and clindamycin phosphate in D5W or NaCl (300 mg/50 mL, 600 mg/50 mL, 900 mg/50 mL). To minimize esophageal ulceration, administer orally with a full glass of water. The absorption of clindamycin flavored granules is not adversely affected by co-administration with food. When administered intramuscularly, the sites must require rotation with no dose exceeding 600 mg in a single injection. Clindamycin is administered by intravenous (IV) intermittent infusion over at least 10 to 60 minutes at a maximum rate of 30 mg/minutes. The final concentration of the IV solution should not exceed 18 mg/mL. Pediatric dosing for neonates is 15 to 20 mg/kg per day, given IM/IV divided over 6 to 8 hours. Infants, children, and adolescents are treated with 8 to 40 mg/kg per day orally divided over 3 to 4 doses. For IM/IV administration, 20 to 40 mg/kg per day can be given over 3 to 4 doses.

The adverse effects of clindamycin vary based on how its mode of administration. The most common side effects experienced with topical use include pruritis, xeroderma, erythema, burning, exfoliation, or oily skin. With intravaginal administration, the most common side effects are vaginal candidiasis, pruritis, vulvovaginal disease, and vulvovaginitis. The primary adverse effects of clindamycin with systemic administration are pseudomembranous colitis, nausea, vomiting, and diarrhea, which is a result of clindamycin destroying much of the GI tract’s healthy flora. Clostridium difficile is allowed to overgrow in this environment. Toxins A and B, which are produced by C. difficile, cause Clostridium difficile-associated diarrhea (CDAD). If suspected, a stool antigen test should is in order. Severe cases that result from hypertoxic-producing strains occur in an increase in morbidity and mortality, which may require colectomy for definitive treatment. Other adverse effects include thrombophlebitis or metallic taste with IV administration, azotemia, agranulocytosis, anaphylactic shock, abscess formation, induration, or irritation at the site of IM injection.[5][6][7][8]

Clindamycin is contraindicated in patients with a history of pseudomembranous colitis or ulcerative colitis. Care is also necessary for antibiotic use as bacterial and fungal superinfections may occur. It is also contraindicated in patients with hypersensitivity to clindamycin, lincomycin, or any of their components. Special care must also be taken in patients with atopic dermatitis as colonization is more prevalent in this patient population. The pathogenicity of skin infections is higher in this population; this is important for future infections as antibiotic resistance is a problematic complication.