Tuberculosis.

Hepatitis(rare). Peripheral neuritis, nausea, vomiting, Epigastric distress,visual disturbances, Hepatitis, fever, rash, Pyridoxine deficiency, Hyperglycaemia, Hepatotoxicity (enhanced by rifampicin).

Drug induced hepatic disease.

Special precautions: Renal impairment.

Indications:

Tuberculosis.

Dosage:

Take on an empty stomach at least 1 hour before or 2 hours after meals. Used in conjunction with other anti-tubercular agents.

Adults- 300mg/day in a single dose. Infants and children- 10 to 20mg/kg/day(upto 300mg total) in a single dose..

Diffuse Hepacellular Damage

Drugs causing Adverse Reactions- (385 )

1. Halothane

2. Methoxyfurane

3. Methyldopa

4. Isoniazid

5. Rifampin

6. Aminosalicylic acid

7. Ethionamide

8. Phenytoin and hydantoin

9. Acetoaminophen ( Paracetamol )

10. Salicylates

11. Allopurinol

12. Sulfonamides

13. Tetracycline

14. Erythromycin estrolate

15. Propylthiouracil

16. Methimazole

17. Oxyphenisatin

18. Methotrexate

19. Pyridium

20. Propoxyphene

21. Monoamine oxidase inhibitors Acne- ( 243 )

 Acne vulgaris is is a seriouys problem especially common during adolescence and its therapy is complex and prolonged.

Drugs causing adverse reactions- ( 385 )

1. Anabolic and androgenic steroids

2. Corticosteroids

3. Bromides

4. Iodides

5. Oral contraceptives

6. Isoniazid

7. Troxidone

1.Take on an empty stomach, atleast 1 hour before or 2 hours after meals; it may be taken with food to decrease GI upset.

2. Take as directed, do not discontinue except on advise of physcian.

3. Minimise daily alcohol consumption while on INH, due to increased hepatitis risk.

4. Notify physician of weakness, fatigue, loss of appetite, nausea, and vomiting, yellowing of skin or eyes, darkening of urine, or numbness or tingling in hands and feet

5.Allergies- tell your doctor if you have ever had any unusual or allergic reaction to isoniazid, ethionamide, pyrazinamide, or niacin . Also tell your doctor if youare allergic to any other substances, such as foods, presrvatives or dyes.

6. Diet- most medicines contain more than just the active ingredient and many liquid preparations contain alcohol. Make sure that your doctor knows if you are on alow sodium .low sugar or other special diet.

7.Pregnancy - tuberculosis is a very serious disease and many women have been treated with isoniazid during pregancy with no problems to their babies

8.Breast feeding- isoniazid has not been reported to cause problems in nursing babies

9 Children - isoniazid can cause serios side effects in any patient.

10. Elderly- hepatitis is likely to occur in older patients

11. Other medicines - Acetaminophen or Amiodarone or Anabolic steroids or Androgens or Antithyroid agents or Carmustine or Chloroquine or Dantralene or Daunorubicin or Disulfram or Divalproex or Estrogens or Gold salts or Hydroxychloroquine or Mercaptopurine or Methotexate or Methyldopa or Naltexone or Oral contraceptives or Other anti-infective by mouth or injection or Phenithiazines or Plicamycin or Valproic acid or Carbamazepine or Phenytoin - these medicines may also be an increased chance of side effects of carbamazipine or phenytoin

Disulram - this medicine may increase the chance of liver damage and side effects Ketoconazole or Rifampicin - use of these medicines with isoniazid can lower the blood levels of ketoconazole or rifampicin, decreasing their effects

12. Other medical problems - Tell your doctor if you have any other medical problems especially -

Alcohol abuse or Liver disease - there is an increasecchgance of hepatitis with daily drinking of alcohol

Kidney disease- an increased chance ofvside effects in patients with severe kidney disease

Seizure disorders  increased chance of seiziures and convulsions

13. Missed dose - If you miss a dose of this medicine, take it as soon as possible. however, if it is almost time for the next dose, skip the missed dose. Do not double doses.

14. Storage - Keep out of reach of children. Store away from heat or direct sunlight. Do not store the capsule in bathroom, near the kitchen sink, or in other damp places.

15. Outdated medicines - Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of reach of children.

Pharmacology:

INH- isoniazid acts against actively growing tubercle bacilli. It is bactericidal and interferes with lipid and nucleic acid biosynthesis in growing organisms.

Pharmacokinetics:

INH is rapidly and completely absorbed orally and parentrally and produces peak levels within 1 to 2 hours; these decline to less than 50% within 6 hours. The rate and extent of absorption is decreased by food. The half-life of INH is widely variable and dependent on acetylator status. Approximately 50% to 70% of a dose of INH is excreted unchanged drug metabolites by the kidneys in 24 hours. Elimination is largely independent of renal function.

Rate and extent of absorption is decreased by food.

Pregnancy:

Prescribe during pregnancy only when therapeutically necessary.

Lactation:

Since isoniazid appears in breast milk, observe breastfed infants of isoniazid mothers for any evidence of adverse effects.