section name header

Pronunciation

eye-soe-NYE-a-zid

Classifications

Therapeutic Classification: antituberculars

Indications

REMS

Action

Therapeutic Effects:

Pharmacokinetics

Absorption: Well absorbed following PO/IM administration.

Distribution: Widely distributed; readily crosses the blood-brain barrier.

Metabolism/Excretion: 50% metabolized by the liver by N-acetyltransferase (rate of acetylation is genetically determined [slow acetylators have isoniazid levels and risk of toxicity; fast acetylators have isoniazid levels and risk for treatment failure]); 50% excreted unchanged by the kidneys.

Half-life: 1–4 hr in patients with normal renal and hepatic function; 0.5–1.6 hr in fast acetylators; 2–5 hr in slow acetylators.

Time/Action Profile

(plasma concentrations)

ROUTEONSETPEAKDURATION
POrapid1–2 hrup to 24 hr
IMrapid1–2 hrup to 24 hr

Contraind./Precautions

Contraindicated in:

Use Cautiously in:

Adv. Reactions/Side Effects

Derm: DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), rash, TOXIC EPIDERMAL NECROLYSIS.

EENT: visual disturbances.

Endo: gynecomastia.

GI: HEPATOTOXICITY, nausea, vomiting.

Hemat: blood dyscrasias.

Neuro: peripheral neuropathy, psychosis, seizures.
Misc: fever.

Interactions

Drug-Drug:

Drug-Food:

Route/Dosage

see Calculator

Availability

(Generic available)

Assessment

Lab Test Considerations: Toxicity and Overdose:

Implementation

Patient/Family Teaching

Evaluation/Desired Outcomes

Canadian Brand Names

Isotamine