Other drug names:	A-Am  An-Az  B  C-Ch  Ci-Cz  D-Dh  Di-Dz  E  F  G  H  I-J  K-L  M-Mh  Mi-Mz  N-Nh  Ni-Nz  O  P-Pl  Pm-Pz  Q-R  S-Sn  So-Sz  T-To  Tp-Tz  U-V  W-Z  0-9

Another commonly used name for isoniazid is INH.Other commonly used names for thiacetazone are thioacetazone; amithiozone.

Isoniazid and thiacetazone (eye-soe-NYE-a-zid and thye-a-SEET-a-zone) combination is used to treat tuberculosis (TB). It is given in combination with other medicines to treat TB.

Isoniazid and thiacetazone combination may cause some serious side effects, including damage to the liver. Liver damage is more likely to occur in patients over 50 years of age. This medicine may also cause a severe skin rash, especially in patients infected with the human immunodeficiency virus (HIV). You and your doctor should talk about the good this medicine will do, as well as the risks of taking it.

To help clear up your TB completely, you must keep taking this medicine for the full time of treatment, even if you begin to feel better. This is very important. It is also important that you do not miss any doses.

Isoniazid and thiacetazone combination is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (Africa; Asia; Latin America)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For isoniazid and thiacetazone combination, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to isoniazid or thiacetazone. Also tell your health care worker if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Isoniazid has not been shown to cause birth defects or other problems in humans and has not been shown to cause birth defects in animals. Studies in rats and rabbits have shown that isoniazid may increase the risk of miscarriage. However, tuberculosis is a very serious disease and many women have been treated with isoniazid during pregnancy with no problems occurring in their babies. Studies on the effects of thiacetazone in pregnancy have not been done in humans or animals.

Breast-feeding—Isoniazid passes into the breast milk. However, isoniazid has not been reported to cause problems in nursing babies. Also, there is not enough isoniazid in breast milk to protect or treat babies who have been exposed to tuberculosis. It is not known whether thiacetazone passes into breast milk.

Children—Isoniazid and thiacetazone combination can cause serious side effects in any patient. Therefore, it is especially important that you discuss with the child's doctor the good that this medicine may do as well as the risks of using it.

Older adults—Hepatitis may be especially likely to occur in older patients, who are usually more sensitive than younger adults to the effects of isoniazid.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking isoniazid and thiacetazone combination, it is especially important that your health care worker know if you are taking any of the following:

• Acetaminophen (e.g., paracetamol, Tylenol) (with long-term, high-dose use) or
• Amiodarone (e.g., Cordarone) or
• Anabolic steroids (nandrolone [e.g., Anabolin], oxandrolone [e.g., Anavar], oxymetholone [e.g., Anadrol], stanozolol [e.g., Winstrol]) or
• Androgens (male hormones) or
• Antithyroid agents (medicine for overactive thyroid) or
• Carmustine (e.g., BiCNU) or
• Chloroquine (e.g., Aralen) or
• Dantrolene (e.g., Dantrium) or
• Daunorubicin (e.g., Cerubidine) or
• Divalproex (e.g., Depakote) or
• Estrogens (female hormones) or
• Etretinate (e.g., Tegison) or
• Gold salts (medicine for arthritis) or
• Hydroxychloroquine (e.g., Plaquenil) or
• Mercaptopurine (e.g., Purinethol) or
• Methotrexate (e.g., Mexate) or
• Methyldopa (e.g., Aldomet) or
• Naltrexone (e.g., Trexan) (with long-term, high-dose use) or
• Oral contraceptives (birth control pills) containing estrogen or
• Other anti-infectives by mouth or by injection (medicine for infection) or
• Phenothiazines (acetophenazine [e.g., Tindal], chlorpromazine [e.g., Thorazine], fluphenazine [e.g., Prolixin], mesoridazine [e.g., Serentil], perphenazine [e.g., Trilafon], prochlorperazine [e.g., Compazine], promazine [e.g., Sparine], promethazine [e.g., Phenergan], thioridazine [e.g., Mellaril], trifluoperazine [e.g., Stelazine], triflupromazine [e.g., Vesprin], trimeprazine [e.g., Temaril]) or
• Plicamycin (e.g., Mithracin) or
• Rifampin (e.g., Rifadin) or
• Valproic acid (e.g., Depakene)—These medicines may increase the chance of liver damage if taken with isoniazid and thiacetazone combination

• Carbamazepine (e.g., Tegretol) or
• Phenytoin (e.g., Dilantin)—These medicines may increase the chance of liver damage if taken with isoniazid and thiacetazone combination. There may also be an increased chance of side effects of carbamazepine and phenytoin

• Disulfiram (e.g., Antabuse)—Use of this medicine with isoniazid and thiacetazone combination may increase the chance of liver damage and side effects, such as dizziness, lack of coordination, irritability, and trouble in sleeping

• Ketoconazole (e.g., Nizoral)—Use of ketoconazole with isoniazid and thiacetazone combination can lower the blood levels of ketoconazole decreasing its effects

Other medical problems—The presence of other medical problems may affect the use of isoniazid and thiacetazone combination. Make sure you tell your doctor if you have any other medical problems, especially:

• Alcohol abuse (or history of) or
• Liver disease—There may be an increased chance of hepatitis with daily drinking of alcohol or in patients with liver disease

• Human immunodeficiency virus (HIV) infection—There may be an increased chance of severe skin rash in patients with HIV infection

• Kidney disease (severe)—There may be an increased chance of side effects in patients with severe kidney disease

• Seizure disorders such as epilepsy—There may be an increased chance of seizures (convulsions) in some patients

If you are taking isoniazid and thiacetazone combination and it upsets your stomach, take it with food. Antacids may also help. However, do not take aluminum-containing antacids within 1 hour of taking isoniazid and thiacetazone combination. They may keep this medicine from working properly.

To help clear up your tuberculosis (TB) completely, it is very important that you keep taking this medicine for the full time of treatment, even if you begin to feel better after a few weeks. You may have to take it every day for as long as 8 to 12 months. It is important that you do not miss any doses.

Your doctor may also want you to take pyridoxine (e.g., Hexa-Betalin, vitamin B ₆) every day during treatment with isoniazid and thiacetazone combination to help prevent or lessen some of the side effects of the combination. Pyridoxine is not usually needed in children who receive enough pyridoxine in their diet. If pyridoxine is needed, it is very important to take it every day along with this medicine. Do not miss any doses.

Dosing—

The dose of isoniazid and thiacetazone combination will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of isoniazid and thiacetazone combination. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take depends on the strength of the medicine.

• For oral dosage form (tablets):
  • For treatment of tuberculosis:
    • Adults, teenagers, and children over 40 kilograms (kg) (88 pounds) of body weight—300 milligrams (mg) of isoniazid and 150 mg of thiacetazone once a day.
    • Children up to 10 kg (22 pounds) of body weight—50 mg of isoniazid and 25 mg of thiacetazone once a day.
    • Children 10 to 20 kg (22 to 44 pounds) of body weight—100 mg of isoniazid and 50 mg of thiacetazone once a day.
    • Children 20 to 30 kg (44 to 66 pounds) of body weight—200 mg of isoniazid and 100 mg of thiacetazone once a day.
    • Children 30 to 40 kg (66 to 88 pounds) of body weight—250 mg of isoniazid and 125 mg of thiacetazone once a day.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is very important that your doctor or health care worker check your progress at regular visits. Also, check with your doctor or health care worker immediately if blurred vision or loss of vision, with or without eye pain, occurs during treatment. Your doctor may want you to have your eyes checked by an ophthalmologist (eye doctor).

It is also very important to check with your doctor or health care worker immediately if you develop any kind of rash. This medicine may cause a very serious rash in any patient, but it occurs more often in patients with human immunodeficiency virus (HIV) infection. If you notice a rash, stop taking this medicine and see your health care worker immediately.

If your symptoms do not improve within 2 to 3 weeks, or if they become worse, check with your doctor or health care worker.

Certain foods such as cheese (Swiss or Cheshire) or fish (tuna, skipjack, or Sardinella) may rarely cause reactions in some patients taking isoniazid and thiacetazone combination. Check with your doctor or health care worker if redness or itching of the skin, hot feeling, fast or pounding heartbeat, sweating, chills or clammy feeling, headache, or lightheadedness occurs while you are taking this medicine.

Liver problems may be more likely to occur if you drink alcoholic beverages regularly while you are taking this medicine. Also, the regular use of alcohol may keep this medicine from working properly. Therefore, you should strictly limit the amount of alcoholic beverages you drink while you are taking isoniazid and thiacetazone combination.

If this medicine causes you to feel very tired or very weak or causes clumsiness; unsteadiness; a loss of appetite; nausea; numbness, tingling, burning, or pain in the hands and feet; or vomiting, check with your health care worker immediately. These may be early warning signs of serious liver or nerve problems.

For diabetic patients:
• This medicine may affect the results of some urine sugar tests. Check with your doctor or health care worker before changing your diet or the dosage of your diabetes medicine.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or health care worker immediately if any of the following side effects occur:

• More common
  • Aching joints and muscles;  clumsiness or unsteadiness;  dark urine;  difficulty in swallowing;  loss of appetite;  nausea or vomiting;  numbness, tingling, burning, or pain in hands and feet;  redness, blistering, peeling, or loosening of skin;  unusual tiredness or weakness;  yellow eyes or skin 
  
  

• Rare
  • Blurred vision or loss of vision, with or without eye pain;  convulsions (seizures);  fever and sore throat;  joint pain;  mental depression;  mood or other mental changes;  redness of eyes with oozing;  skin rash ;  unusual bleeding or bruising 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor or health care worker if any of the following side effects continue or are bothersome:

• More common
  • Diarrhea;  dizziness;  stomach pain 
  
  

Dark urine and yellowing of the eyes or skin (signs of liver problems) are more likely to occur in patients over 50 years of age.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor or health care worker.

Developed: 06/22/1995