JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D III Year PHARMACOTHERAPEUTICS - II Previous Question Paper (October/November - 2019 - R08)

The treatment of tuberculosis (TB) follows a standardized regimen divided into an intensive phase and a continuation phase to ensure bactericidal activity and prevent the emergence of drug resistance.

The standard 6-month regimen consists of:

1. Intensive Phase (2 months): Isoniazid (INH), Rifampicin (RIF), Pyrazinamide (PZA), and Ethambutol (EMB) administered daily.
2. Continuation Phase (4 months): Isoniazid and Rifampicin administered daily or intermittently.

Safety monitoring parameters are essential due to the hepatotoxic and neurotoxic potential of these agents:

• Hepatotoxicity: Monitor baseline and periodic liver function tests (LFTs) including serum transaminases and bilirubin, particularly for INH, RIF, and PZA. Patients must be educated to report jaundice, dark urine, or abdominal pain.
• Ocular Toxicity: Baseline and monthly visual acuity and color vision testing are required for patients on Ethambutol to monitor for optic neuritis.
• Peripheral Neuropathy: Monitor for numbness or tingling in extremities, especially with INH therapy; pyridoxine (Vitamin B6) supplementation is standard to mitigate this risk.
• Hyperuricemia: Monitor serum uric acid levels in patients receiving PZA, as it may precipitate gout.
• Ototoxicity: If streptomycin is included in the regimen, monitor for hearing loss and vestibular dysfunction.

Surgical antibiotic prophylaxis aims to reduce the incidence of surgical site infections (SSIs) by achieving adequate tissue concentrations of the antibiotic at the time of incision.

Key principles and agents include:

• Timing: Antibiotics are administered intravenously within 60 minutes prior to the surgical incision to ensure peak serum levels.
• First-generation Cephalosporins: Cefazolin is the drug of choice for most clean and clean-contaminated procedures (e.g., cardiothoracic, orthopedic, and vascular surgeries) due to its excellent activity against Staphylococcus aureus and skin flora.
• Second-generation Cephalosporins: Cefoxitin or Cefotetan are often used for colorectal or gynecological procedures to provide broader coverage against anaerobic organisms.
• Alternative Agents: In patients with severe beta-lactam allergies, Vancomycin or Clindamycin is utilized. Vancomycin is preferred for procedures involving high risks of MRSA colonization.
• Duration: Prophylaxis is typically discontinued within 24 hours post-operatively to minimize the risk of developing antimicrobial resistance and adverse effects.