The lincosamides, lincomycin and clindamycin, are inhibitors of bacterial protein synthesis. Drugs in this class share the same binding site as that of macrolides and amphenicols; however, they differ in chemical structure. Lincosamides target the 50S ribosomal subunit and interfere with transpeptidation. The antimicrobial coverage of lincosamides encompasses gram-positive cocci (including MRSA) and anaerobes. Clindamycin can also be used to treat toxic shock syndrome and necrotizing fasciitis owing to its antitoxin effect. Diarrhea is a common adverse effect, and clindamycin is often associated with a higher risk of Clostridioides difficile colitis.

Last update:

Table of Contents

Share this concept:

Share on facebook
Share on twitter
Share on linkedin
Share on reddit
Share on email
Share on whatsapp

Chemistry and Pharmacodynamics

Chemical structure

  • The chemical structure consists of amino acid and sugar moieties.
  • Lincomycin is the protype drug.
  • Clindamycin is a chlorinated derivative.
chemical structure of clindamycin Lincosamides

Chemical structure of clindamycin

Image: “Clindamycin” by Jü. License: Public Domain

Mechanism of action

  • Inhibits bacterial protein synthesis by binding reversibly to the 50S ribosomal subunit: 
    • Binds near the peptidyltransferase center → prevents peptidyltransferase from adding amino acids to the growing peptide (prevents transpeptidation)
    • Similar binding site as that of macrolides and chloramphenicol
  • Limits bacterial growth → bacteriostatic
  • Can exert a time-dependent killing effect for some bacteria
  • Additional effect: inhibits the production of staphylococcal and streptococcal toxins
Site of action Clindamycin Lincosamides

Site of action of clindamycin at the 50S ribosomal subunit

Image by Lecturio. License: CC BY-NC-SA 4.0


Since lincomycin is rarely used, the pharmacokinetics of clindamycin are have been listed:

Absorption and distribution

  • Rapid absorption
  • Protein bound
  • Taken up by phagocytic cells
  • Widely distributed in body fluids, bone, and tissues
  • Crosses placenta
  • Does not cross the blood-brain barrier

Metabolism and excretion

  • Metabolism: primarily by CYP3A4
  • Excretion:
    • Urine
    • Feces/bile


Antimicrobial coverage

  • Gram-positive microbes:
    • Streptococcus
    • Staphylococcus (including MRSA)
  • Anaerobes:
    • Bacteroides
    • Clostridium perfringens
    • Fusobacterium
    • Prevotella melaninogenicus
    • Peptostreptococcus

Type of infections

  • Skin and soft tissue infections:
    • Acne
    • Cellulitis
  • Respiratory infections:
    • Oral infections
    • Pneumonia 
    • Lung abscess
  • Bone and joint infections:
    • Osteomyelitis
    • Prosthetic joint infection
    • Septic arthritis
  • Intraabdominal infections
  • Gynecologic infections:
    • Bacterial vaginosis
    • Pelvic inflammatory disease
    • Endometritis
  • Used as part of combination therapy for:
    • Babesiosis
    • Toxoplasmosis
    • Pneumocystis jirovecii pneumonia
    • Toxic shock syndrome and necrotizing fasciitis (antitoxin effect)

Adverse Effects and Contraindications

Adverse effects

  • Topical:
    • Pruritis
    • Xeroderma
    • Erythema
    • Exfoliation
  • Vaginal:
    • Candidiasis
    • Vulvovaginitis
  • Systemic:
    • GI upset and diarrhea
    • Pseudomembranous colitis (Clostridioides difficile)
    • Esophagitis
    • Metallic taste
    • Azotemia
    • Agranulocytosis
    • Allergic reactions:
      • Erythema multiforme
      • Stevens-Johnson syndrome
      • Anaphylaxis


  • History of C. difficile infections
  • History of lincosamide allergy

Drug interactions

  • Inducers of CYP3A4: ↓ clindamycin concentrations
  • Neuromuscular blocking agents: ↑ neuromuscular blocking effect
  • Should not be used in combination with macrolides or chloramphenicol (due to the same ribosomal target site)

Mechanisms of Resistance

There are 3 main routes of resistance:

  • Target site modification: 
    • Ribosomal methylation or mutation prevents the binding of the antibiotic to its ribosomal target. 
    • Most prevalent mechanism of resistance to lincosamides
  • Efflux pumps
  • Enzymatic inactivation (uncommon, mostly seen in Staphylococcus)

Comparison of Antibiotics

The following table compares several classes of bacterial protein synthesis inhibitor antibiotics:

Table: Comparison of several classes of bacterial protein synthesis inhibitor antibiotics
Drug classMechanism of actionCoverageAdverse effects
  • Bind to the 50S subunit
  • Prevent transpeptidation
  • Gram positives
  • Gram negatives
  • Atypicals
  • GI upset
  • Optic neuritis
  • Aplastic anemia
  • Gray baby syndrome
  • Bind to the 50S subunit
  • Prevent transpeptidation
  • Gram-positive cocci:
    • MSSA
    • MRSA
    • Streptococcus
  • Anaerobes
  • GI upset
  • Allergic reactions
  • Pseudomembranous colitis
  • Bind to the 50S subunit
  • Prevent transpeptidation
  • Gram positives
  • Gram negatives
  • Atypicals
  • Mycobacterium avium complex
  • GI upset
  • QT prolongation
  • Hepatotoxicity
  • Myasthenia gravis exacerbation
  • Bind to the 23S rRNA of the 50S subunit
  • Prevent initiation complex formation
Gram-positive cocci:
  • MSSA
  • MRSA
  • VRE
  • Streptococcus
  • Myelosuppression
  • Neuropathy
  • Lactic acidosis
  • Serotonin syndrome
rRNA: ribosomal RNA
VRE: vancomycin-resistant Enterococcus
Antibiotic sensitivity chart

Antibiotic sensitivity:
Chart comparing the microbial coverage of different antibiotics for gram-positive cocci, gram-negative bacilli, and anaerobes.

Image by Lecturio. License: CC BY-NC-SA 4.0


  1. Deck, D.H., Winston, L.G. (2012). Tetracyclines, macrolides, clindamycin, chloramphenicol, streptogramins, & oxazolidinones. In Katzung, B.G., Masters, S.B., Trevor, A.J. (Eds.), Basic & Clinical Pharmacology (12th edition, pp. 809-819).
  2. Leclercq, R. (2002). Mechanisms of resistance to macrolides and lincosamides: Nature of the resistance elements and their clinical implications. Clinical Infectious Diseases, 34(4), 482-492.
  3. Johnson, M. (2020). Clindamycin: An overview. In Bond, S. (Ed.), UpToDate. Retrieved June 30, 2021, from
  4. Murphy, P.B., Bistas, K.G., Le, J.K. (2020). Clindamycin. StatPearls. Retrieved June 30, 2021, from
  5. Werth, B.J. (2020). Clindamycin. MSD Manual Professional Version. Retrieved June 30, 2021, from

Study on the Go

Lecturio Medical complements your studies with evidence-based learning strategies, video lectures, quiz questions, and more – all combined in one easy-to-use resource.

Learn even more with Lecturio:

Complement your med school studies with Lecturio’s all-in-one study companion, delivered with evidence-based learning strategies.

🍪 Lecturio is using cookies to improve your user experience. By continuing use of our service you agree upon our Data Privacy Statement.