Drug Interaction:
Interacting drugs- summary
Rifampicin + Isoniazid +
Paracetamol
Paracetamol levels are increased by INH leading to liver toxicity.
Oral contraceptives
Failure of oral contraceptives.
Phenytoin
Decreased excretion of phenytoin.
Methadone / Oral hypoglycemics/ Digoxin / Quinidine / Dapsone / Steroids
Decreased pharmacological activity of methadone, oral
hypoglycaemics digoxin, quinidine, dapsone and steroids.
Antacids
Antacids reduce the absorption of both drugs.
Liver enzymes
Rifampicin induces while INH inhibits liver enzymes. Interactions diffficult
to predict.
Vitamin D3
Rifampicin+INH reduce levels of 125 dihydroxy Vitamin D3.
Adverse Reaction:
Liver damage, hyperuricaemia,acute gout, arthritis, Neuropathies, convulsion, cutaneous syndrome, Flushing, itching and rash.
Hypersens to ioniazid, skin rash, liver, Lymphanopathy,vasculitis, rarely SLE, Flu like syndrome with rifampicin during intermitant therapy.
Contra-Indications:
Hyperesens, jaundice, acute liver disease, biliary obstruction.
Special precautions:
Impaired liver function, very young or malnourished patients, Patients with soft contact lenses. Pyridoxine deficiency states, hyperuricaemia.
Dosages/ Overdosage Etc:
Tuberculosis
Dosage-
1 tab daily 30 minutes before breakfast
Patient Information:
1. Allergies- tell your doctor if you have ever had any unusual or allergic reaction to rifampicin, ethionamide or isoniazid or pyrazinamide. Also tell your doctor if you are allergic to any other substances, such as foods, presevatives or dyes.
2..Pregnancy - pregnant women with tuberculosis should be treated with TB medicines including rifampicin and isoniazid. Rifampicin and isoniazid combination has not been shown to cause birth defects or other problems.
3..Breast feeding- rifampicin and isoniazid both pass into the breast milk. However it has not been reported cause problems in nursing babies
4.Children-rifampoicin and isoniazid combination is not recommended for children.
5. Elderly- dark urine and yellowing of the eyes or skin are more likely to occur in patients over 50 years of who are taking isoniazid containg medicines.
6.Other medicines - Acetoaminophen or Amiodarone or Anabolic steroids or Androgens or Antithyroid agents or Carbamazepine or Carmustine or Chloroquine or Dantrolene or Daunorubicin or Dissulfram or Divalproex or Etretinate or Gold salts or Hydroxychloroquine Mercaptopurine or Methyldopa or Naltrexone or Other anti-infectives by mouth or Phenothiazines or Pilcamycin or Valproic acid - therse medicines may increase the chance for liver damage if taken with rifampicin and isoniazid combination Anticoagulants or Aminophylline or Antidiabetics or Chloramphenicol or Corticosteroids or Digitalis glycosides or Disopyramide or Fluconazole or Itraconazole or Ketoconazole or Methadone or Methotrexate or Mexilitine or Oxytriphylline or Qunidine or Ritonavir or Theophylline or Tocainide or Verapramil - rifampicin and isoniazid combination may decrease or decrease the effects of these medicines Disulfram - this medicine may increase the chance of liver damage Estrogens or Oral contraceptives or Phenytoin - rifampicin and isinoazid combination may decrease the effects of these medicines. If you are taking oral contraceptives this may increase the chance of pregnancy. May also increase the chance of liver damage if taken with rifampicin and isoniazid combination.
7. Other medical problems - Tell your doctor if you have any other medical problems especially - Alcohol abuse or Liver disease - there may be an increased getting hepatitis ifyou are take this medicine and drink alcohol daily. Kidney disesase- increased chance of side effects
8. 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.
9. 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.
10. Outdated medicines - Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of reach of children.