Isoniazid Tab

Antitubercular; extralabel use in horses for Rhodococcus equi infections; mycobacterial infections in small animals. Bactericidal antibiotic (isoniazid / INH). Mechanism: prodrug activated by mycobacterial catalase-peroxidase (KatG) → inhibits InhA (enoyl-ACP reductase) → blocks mycolic acid synthesis in mycobacterial cell wall → bactericidal against actively dividing Mycobacterium. Also inhibits DNA synthesis. Used for Rhodococcus equi in horses (extralabel). Key information Used for equine leucoencephalomalacia and neurological cases. Monitor liver enzymes — hepatotoxic. Pyridoxine (B6) supplementation may be given concurrently. Store at room temperature.

Oral tablets: Administer orally. May be given with food to improve compliance and reduce GI upset. Administer on an empty stomach for optimal absorption. for best absorption (may give with food if GI upset). Supplement pyridoxine (B6) concurrently. Administer at consistent times. Store at room temperature; protect from light. If a dose is missed Administer as soon as you remember. If it is almost time for the next scheduled dose, skip the missed dose and resume the normal schedule. Never double up doses to make up for a missed one.

Hepatotoxicity (most serious — monitor liver enzymes). Peripheral neuropathy (pyridoxine/B6 deficiency — supplement B6 concurrently). GI: nausea, vomiting, anorexia. CNS: seizures with overdose (pyridoxine-responsive). Lupus-like syndrome (prolonged use). Drug interactions: CYP2E1 inhibitor.

For animals Monitor liver enzymes with prolonged use. — monitor liver enzymes. Supplement pyridoxine (B6) to prevent peripheral neuropathy. Drug interaction: CYP2E1 inhibitor — increases levels of some anesthetic agents. Use with caution in pregnant animals. For people handling this medication Wash hands thoroughly with soap and water after handling. Avoid contact with eyes; if contact occurs, flush with water for 15 minutes and seek medical attention. Keep out of reach of children. If accidental ingestion occurs, contact Poison Control (1-800-222-1222). Antimycobacterial — Wash hands thoroughly with soap and water after handling. after handling. Keep out of reach of children. Pregnant women and women of childbearing age should avoid contact. Supplement B6 if handling frequently. Keep out of reach of children.

Contact your veterinarian immediately. Isoniazid overdose causes severe acute neurotoxicity: seizures, metabolic acidosis, and vomiting. Treat with pyridoxine (Vitamin B6) and anticonvulsants. Medical emergency. Contact your veterinarian, a veterinary emergency clinic, or the ASPCA Animal Poison Control Center (888-426-4435) immediately. Do not induce vomiting unless specifically directed by a veterinary professional.