Severe and sometimes fatal hepatitis associated with isoniazid therapy may occur and may develop even after many months of treatment. The risk of developing hepatitis is age related. Approximate case rates by age are: 0 per 1,000 for persons under 20 years of age, 3 per 1,000 for persons in the 20-34 year age group, 12 per 1,000 for persons in the 35-49 year age group, 23 per 1,000 for persons in the 50-64 year age group, and 8 per 1,000 for persons over 65 years of age. The risk of hepatitis is increased with daily consumption of alcohol. Precise data to provide a fatality rate for isoniazid-related hepatitis is not available; however, in a U.S. Public Health Service Surveillance Study of 13,838 persons taking isoniazid, there were 8 deaths among 174 cases of hepatitis.
Therefore, patients given isoniazid should be carefully monitored and interviewed at monthly intervals. Serum transaminase concentration becomes elevated in about 10-20 percent of patients, usually during the first few months of therapy, but it can occur at any time. Usually, enzyme levels return to normal despite continuance of drug, but in some cases progressive liver dysfunction occurs. Patients should be instructed to report immediately any of the prodromal symptoms of hepatitis, such as fatigue, weakness, malaise, anorexia, nausea, or vomiting. If these symptoms appear or if signs suggestive of hepatic damage are detected, isoniazid should be discontinued promptly, since continued use of the drug in these cases has been reported to cause a more severe form of liver damage.
Patients with tuberculosis should be given appropriate treatment with alternative drugs. If isoniazid must be reinstituted, it should be reinstituted only after symptoms and laboratory abnormalities have cleared. The drug should be restarted in very small and gradually increasing doses and should be withdrawn immediately if there is any indication of recurrent liver involvement. Treatment should be deferred in persons with acute hepatic diseases .
Severe and sometimes fatal hepatitis has been reported with isoniazid therapy and may occur even after many months of treatment. The risk for hepatitis increases with advancing age and alcohol use. Monthly clinical evaluation and liver function tests should be performed .
Commonly used brand name(s):
In the U.S.
Available Dosage Forms:
Therapeutic Class: Antitubercular Combination
Chemical Class: Rifamycin
Rifampin and isoniazid is a combination antibiotic and anti-infective medicine. This combination medication is used to treat tuberculosis (TB). It may be taken alone or with one or more other medicines for TB.
To help clear up your tuberculosis (TB) infection completely, you must keep taking rifampin and isoniazid 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.
Rifampin and isoniazid combination is available only with your doctor's prescription.
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 rifampin and isoniazid, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to rifampin and isoniazid or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Rifampin and isoniazid combination is not recommended for use in children.
Liver problems are more likely to occur in patients over 50 years of age who are taking isoniazid-containing medicines.
|All Trimesters||C||Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.|
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.Rifampin
Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.
Using rifampin and isoniazid with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using rifampin and isoniazid with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using rifampin and isoniazid with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Using rifampin and isoniazid with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use rifampin and isoniazid, or give you special instructions about the use of food, alcohol, or tobacco.
Using rifampin and isoniazid with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use rifampin and isoniazid, or give you special instructions about the use of food, alcohol, or tobacco.
The presence of other medical problems may affect the use of rifampin and isoniazid. Make sure you tell your doctor if you have any other medical problems, especially:
If rifampin and isoniazid upsets your stomach, take it with food. Antacids may also help. However, do not take aluminum-containing antacids within 1 hour of the time you take rifampin and isoniazid combination. They may keep rifampin and isoniazid from working properly.
To help clear up your tuberculosis (TB) completely, it is very important that you keep taking rifampin and isoniazid 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 1 to 2 years or more. 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 to help prevent or lessen some of the side effects of isoniazid. If it is needed, it is very important to take pyridoxine every day along with rifampin and isoniazid. Do not miss any doses.
The dose of rifampin and isoniazid 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 rifampin and isoniazid. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
If you miss a dose of rifampin and isoniazid, 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.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
It is very important that your doctor check your progress at regular visits. In addition, you should check with your doctor immediately if blurred vision or loss of vision, with or without eye pain, occurs during treatment. He or she may want you to have your eyes checked by an ophthalmologist (eye doctor).
If your symptoms do not improve within 2 to 3 weeks, or if they become worse, check with your doctor.
Oral contraceptives (birth control pills) containing estrogen may not work properly if you take them while you are taking rifampin and isoniazid combination. Unplanned pregnancies may occur. You should use a different means of birth control while you are taking rifampin and isoniazid. If you have any questions about this, check with your health care professional.
Liver problems may be more likely to occur if you drink alcoholic beverages regularly while you are taking rifampin and isoniazid. Also, the regular use of alcohol may keep rifampin and isoniazid from working properly. Therefore, you should strictly limit the amount of alcoholic beverages you drink while you are taking rifampin and isoniazid.
Certain foods such as cheese (Swiss or Cheshire) or fish (tuna, skipjack, or Sardinella) may rarely cause reactions in some patients taking isoniazid-containing medicines. Check with your doctor if redness or itching of the skin, hot feeling, fast or pounding heartbeat, sweating, chills or clammy feeling, headache, or lightheadedness occurs after eating these foods while you are taking rifampin and isoniazid.
rifampin and isoniazid will cause the urine, stool, saliva, sputum, sweat, and tears to turn reddish-orange to reddish-brown. This is to be expected while you are taking rifampin and isoniazid. This effect may cause soft contact lenses to become permanently discolored. Standard cleaning solutions may not take out all the discoloration. Therefore, it is best not to wear soft contact lenses while taking rifampin and isoniazid. This condition will return to normal once you stop taking rifampin and isoniazid. Hard contact lenses are not discolored by rifampin and isoniazid. If you have any questions about this, check with your doctor.
If rifampin and isoniazid 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, stop taking it and check with your doctor immediately. These may be early warning symptoms of more serious liver or nerve problems that could develop later.
Rifampin and isoniazid combination may cause blood problems. These problems may result in a greater chance of certain infections, slow healing, and bleeding of the gums. Therefore, you should be careful when using regular toothbrushes, dental floss, and toothpicks. Dental work should be delayed until your blood counts have returned to normal. Check with your medical doctor or dentist if you have any questions about proper oral hygiene (mouth care) during treatment.
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 immediately if any of the following side effects occur:More common
Some 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. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:More common
rifampin and isoniazid commonly causes reddish-orange to reddish-brown discoloration of urine, stool, saliva, sputum, sweat, and tears. This side effect does not usually require medical attention.
Dark urine and yellowing of the eyes or skin (signs of liver problems) are more likely to occur in patients 50 years of age and older.
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
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