Isoniazid Pharmacology


About Isoniazid
Hydrazine derivative, Antitubercular Agent.
Mechanism of Action of Isoniazid
Isoniazid is a bactericidal drug. I t inhibits the mycolic acid synthesis which is essential for the cell wall formation. It also inhibits DNA, RNA and protein synthesis and cell metabolism. As the results of these bacterial death occurs.
Pharmacokinets of Isoniazid
Absorption: It is rapidly absorbed after oral administration.Distribution: It is very widely distributed in the body.Metabolism: It undergoes metabolism in the liver.Excretion:It is mainly excreted through urine and small amount excreted through bile, breast milk, sputum and saliva.
Onset of Action for Isoniazid
1 - 2 days
Duration of Action for Isoniazid
1 day
Half Life of Isoniazid
1 - 4 hour
Side Effects of Isoniazid
1. Nausea
2 .Vomiting
3. Gastric upset
4. Peripheral neuritis
5. Optic neuritis
6. Atrophy
7. Paresthesia
8. Allergy
9. Fever
12.Lymph adenopathy
Contra-indications of Isoniazid
1. Hypersensitivity to Isoniazide
2. Drug induced hepatic disease
Special Precautions while taking Isoniazid
1.Renal impairment
2.Hepatic impairment
Pregnancy Related Information
Old Age Related Information
Use with caution
Breast Feeding Related Information
Use with caution
Children Related Information
May be used
NEONATES: may be used
Indications for Isoniazid
1.Tuberculosis (pulmonary &extra pulmonary)
Interactions for Isoniazid
Alcohol: Regular ingestion of alcohol is associated with higher incidence of INH-related hepatitis.
Aluminium Salts: Oral absorption of INH reduced leading to decreased serum levels.
Oral anticoagulants: Efficacy of oral anticoagulants increased.
Benzodiazepines: Activity of benzodiazepines that undergo oxidative metabolism is possibly increased.
Carbamazepine: Isoniazid hepatotoxicity & carbamazepine toxicity may occur from concurrent use.
Cycloserine: Increased cycloserine related CNS side effects, especially dizziness.
Disulfiram: Acute behavioural and co-ordination changes.
Enflurane: High output renal failure may occur.
Halothane: Hepatotoxicity and hepatic encephalopathy.
Hydantoins: Serum hydantoin levels increased leading to enhanced pharmacological and toxic effects.
Ketoconazole: Serum concentrations of ketoconazole decreased possibly leading to resistance to antifungal treatment.
Rifampicin: Higher incidence of hepatotoxicity than with either agent alone.
Food: Interaction with tyramine-containing foods since INH has MAOI activity.
Exaggerated response (headache, palpitation, sweating, hypotension, flushing, itching) to foods containing histamine (tuna, sauerkraut juice, yeast extract).

Typical Dosage for Isoniazid
Adult: 200 - 300 mg once daily for 6 months to 24 months depending on the severity of infection
Children:5 - 10 mg / kg body weight / day for 6 months to 24 months depending on the severity of infection.
Schedule of Isoniazid
Storage Requirements for Isoniazid
The drug should be stored at room temperature .Keep away from heat, light and moisture. The vial should be kept at 2 - 8 degree Celsius.
Effects of Missed Dosage of Isoniazid
Take the missed dose as soon as noticed and if it is the time for next dose then skip the missed dose.Continue the regular schedule.Do not double the dose.
Effects of Overdose of Isoniazid
Give supportive measures and treatment. Control seizure by giving Diazepam. Then Pyridoxine is administered followed by gastric lavage. Acidosis can be treated with sodium bicarbonate by parenteral administration. Forced diuresis and dialysis can be done if necessary.

Home Delivery for Isoniazid in Your City

Medicine India is just a publishing medium for medicine related information and does not provide services or sales of medicines including isoniazid.

However, we do publish a comprehensive directory of Pharmacies, Chemists and Druggists in cities all over India. You can use this directory to find the medicine stores in your city (or area) that provide home delivery services for isoniazid and other medicines and health products. Home delivery services for isoniazid may be free or they may cost you depending on the pharmacy and the minimum order requirements. It would be best to get this clarified while placing the order.

Please be aware that you should take isoniazid only if a doctor has recommended or prescribed it. Some or all pharmacies who provide a home delivery service for medicines might insist on a prescription for isoniazid before they complete the sale. You can get this information while placing the order for isoniazid with the pharmacy.

Isoniazid is a generic medicine name and there are several brands available for it. Some of the brands for isoniazid might be better known than isoniazid itself. If the pharmacy that's willing to deliver medicines to your home doesn't have isoniazid in stock, you can ask for one of the branded alternatives for isoniazid.