Clindamycin
Clindamycin is a broad-spectrum **lincosamide antibiotic** widely used in veterinary medicine. It is highly effective against many anaerobic bacteria, gram-positive aerobic cocci (such as *Staphylococcus* and *Streptococcus*), and certain protozoa including *Toxoplasma*, *Neospora*, and *Babesia*. **Clinical Pearls:** * **Excellent Tissue Penetration:** Clindamycin achieves high concentrations in bone, synovial fluid, abscesses, and white blood cells, making it a first-line choice for **osteomyelitis**, **dental infections**, and **deep pyoderma**. * **Toxoplasmosis:** It is a primary treatment for clinical toxoplasmosis in cats and dogs. * **Toxicity in Herbivores:** It is strictly contraindicated in hindgut fermenters (horses, rabbits, rodents) and ruminants due to the risk of fatal clostridial enterocolitis. * **Esophageal Stricture Risk:** In cats, dry-pilling capsules or tablets can cause severe esophagitis and strictures. Always follow oral solid doses with a water bolus or food.
Mechanism: Clindamycin acts by binding to the **50S ribosomal subunit** of susceptible bacteria. * **Mechanism:** It inhibits peptide bond formation (transpeptidation) โ blocks bacterial protein synthesis. * **Effect:** It can be either **bacteriostatic** or **bactericidal**, depending on the drug concentration at the infection site and the specific susceptibility of the organism. * **Resistance:** Complete cross-resistance occurs between clindamycin and lincomycin, and partial cross-resistance occurs with macrolides (like erythromycin) due to overlapping ribosomal binding sites.
Dosing by species
- Susceptible bacterial infections ยท 5-10 mg/kg ยท PO ยท q12h
- Infected wounds, abscesses and dental infections ยท 11-33 mg/kg ยท PO ยท once a day (q24h) ยท Maximum 14 days ยท Do not treat acute infections for more than 3-4 days if no clinical response is seen.
- Sepsis ยท 11 mg/kg ยท IV ยท q12h
- Anaerobic infections ยท 5-10 mg/kg ยท PO, IV ยท q12h
- Intra-abdominal sepsis ยท 5-11 mg/kg ยท IV, SC, PO ยท q8-12h ยท 5-7 days ยท Combined with gentamicin or a parenteral 3rd generation cephalosporin or enrofloxacin
- Pancreatitis ยท 5-11 mg/kg ยท IV, SC, PO ยท q8-12h ยท 3-5 days
- Susceptible respiratory infections ยท 10-15 mg/kg ยท PO, SC ยท q12h
- Surgical prophylaxis for gram-positive aerobes and anaerobic coverage ยท 5-11 mg/kg ยท PO ยท once ยท 16-60 minutes preoperatively
- Toxoplasmosis (to decrease zoonotic risk by reducing shedding period) ยท 25-50 mg/kg ยท PO ยท daily
- Clinical toxoplasmosis ยท 10 mg/kg ยท PO ยท q12h ยท at least 28 days ยท Institute supportive care as needed.
- Enteroepithelial toxoplasmosis ยท 8-16 mg/kg ยท PO, SC ยท q8h ยท 14-28 days
Routes of administration
Contraindications
- Horses
- Rabbits
- Hamsters
- Chinchillas
- Guinea pigs
- Ruminants
- Patients hypersensitive to lincosamides
- Neonatal small animals (generally avoided)
- Known hypersensitivity to lincosamides
Adverse effects
- Gastroenteritis (emesis, loose stools, bloody diarrhea)
- Esophageal injuries (esophagitis, strictures) in cats if dry-pilled
- Hypersalivation or lip smacking in cats after oral administration
- Pain at IM injection site
- Mild, clinically insignificant increases in liver enzymes (AST, ALT, ALP)
- Colitis
- Vomiting
- Diarrhoea
- Oesophagitis (especially in cats)
- Oesophageal stricture (especially in cats)
Drug interactions
- Cyclosporine ยท Clindamycin may reduce cyclosporine levels
- Erythromycin ยท In vitro antagonism when used with clindamycin; concomitant use should probably be avoided
- Neuromuscular blocking agents (e.g., pancuronium) ยท Clindamycin possesses intrinsic neuromuscular blocking activity and should be used cautiously with other neuromuscular blocking agents
- Non-depolarizing muscle relaxants (e.g., tubocurarine) ยท May enhance the neuromuscular blocking effect ยท major
- Neostigmine ยท May antagonize the effects of neostigmine ยท moderate
- Pyridostigmine ยท May antagonize the effects of pyridostigmine ยท moderate
- Macrolides (e.g., erythromycin) ยท Antagonistic antimicrobial effects due to competing binding sites ยท major
- Chloramphenicol ยท Antagonistic antimicrobial effects due to competing binding sites ยท major
- Other lincosamides ยท Antagonistic antimicrobial effects ยท major
- Tubocurarine (and other non-depolarizing muscle relaxants) ยท May enhance the neuromuscular blocking effect ยท moderate
- Lincomycin ยท Complete cross-resistance and antagonistic effect ยท major
Monitoring
- Clinical efficacy
- Adverse effects; particularly severe diarrhea
- Periodic liver and kidney function tests and blood counts if therapy persists for more than 30 days
- Gastrointestinal signs (vomiting, diarrhoea)
- Hepatic and renal function in patients with pre-existing impairment
Overdose
There is little information available regarding overdoses of this drug. * In dogs, oral doses of up to **300 mg/kg/day** for up to one year did not result in toxicity. * Dogs receiving **600 mg/kg/day** developed anorexia, vomiting, and weight loss.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturerโs current label.