What is the pharmacokinetics of isoniazid?
Isonicotinyl hydrazine or isoniazid (INH) has been the mainstay of TB treatment and prevention in both adults and children. When given orally in the fasted state, INH is rapidly absorbed with the maximum concentration (Cmax) occurring 1–2 hours post-dose. Food delays and decreases the extent of absorption.
What is the mechanism of action of isoniazid?
Mechanism of action — The antimicrobial activity of INH is selective for mycobacteria, likely due to its ability to inhibit mycolic acid synthesis, which interferes with cell wall synthesis, thereby producing a bactericidal effect [1].
What is the bioavailability of isoniazid?
Absolute bioavailability in the fasted state and the fed state was 93% and 78% for isoniazid, 87% and 71% for rifampicin and 87% and 82% for ethambutol.
What is the half life of isoniazid?
The plasma half-life of isoniazid in patients with normal renal and hepatic function ranges from 1-4 hours, depending on the rate of metabolism. From 50% to 70% of a dose of isoniazid is excreted in the urine within 24 hours, mostly as metabolites.
How is isoniazid absorbed?
Absorption: Rapidly and completely absorbed from the GI tract after oral administration. INH also is absorbed readily after I.M. injection. Distribution: Distributed widely into body tissues and fluids, including ascitic, synovial, pleural, and cerebrospinal fluids; lungs and other organs; and sputum and saliva.
Is isoniazid an inducer or inhibitor?
Isoniazid is a mechanism-based inhibitor of cytochrome P450 1A2, 2A6, 2C19 and 3A4 isoforms in human liver microsomes.
Is isoniazid soluble in water?
Intellectual property rights: Generic. First synthesized in 1912, first used clinically in 1952. Solubility: Solubility in water: ∼14% at 25ºC, ∼26% at 40ºC; in ethanol: ∼2% at 25ºC, ∼10% in boiling ethanol; in chloroform: ∼0.1%.
How long is isoniazid in your system?
Isoniazid is used to treat tuberculosis (TB). TB is a bacterial infection which mostly affects the lungs, but which can affect any part of your body. It is treatable with a course of medicines which usually lasts for six months in total….About isoniazid.
| Type of medicine | An antituberculosis medicine |
|---|---|
| Available as | Tablets |
Does isoniazid inhibit protein synthesis?
After the addition of INH, the rate of DNA synthesis began to decrease and was abolished within 4 hr. RNA synthesis ceased after 6 hr, and protein synthesis was inhibited after 7 hr. Thus, it appears that inhibition of the synthesis of DNA is one of the earliest events after INH addition.
How is isoniazid excreted?
Excretion: About 75% of a dose is excreted in urine as unchanged drug and metabolites in 24 hours; some drug is excreted in saliva, sputum, feces, and breast milk. Plasma half-life in adults is 1 to 4 hours, depending on metabolic rate. Drug is removed by peritoneal dialysis or hemodialysis.
Does isoniazid need to be fasted?
Isonicotinyl hydrazine or isoniazid (INH) has been the mainstay of TB treatment and prevention in both adults and children. When given orally in the fasted state, INH is rapidly absorbed with the maximum concentration (Cmax) occurring 1–2 hours post-dose. Food delays and decreases the extent of absorption.
How is isoniazid administered?
2.1. Absorption Isoniazid is usually administered orally, but if the patient is critically ill, the drug can be delivered intramuscularly or intravenously as a slow 5-min bolus in 25 ml of normal saline [ 12, 13 ].
Does isoniazid cause hepatotoxicity?
Although isoniazid (INH) has been successful in treating Tuberculosis (TB) since its introduction in 1952, there has been continual reports of drug-associated hepatotoxicity in TB patients. These toxic side effects may reveal more about the recipient of the drug, than the drug itself.
What is the concentration of isoniazid and pyrazinamide?
The assays were validated over the concentration range of 0.112 to 26 mg/L for isoniazid, 0.203 to 81.1 mg/L for pyrazinamide and 0.081 to 5.18 mg/L for ethambutol. The mean percentage accuracies during inter-day sample analysis at low, medium, and high quality control levels,…
