Medically reviewed by Drugs.com. Last updated on Apr 24, 2023.
Severe and sometimes fatal hepatitis has been reported with isoniazid therapy and may occur even after many months of treatment. The risk for hepatitis generally increases with advancing age and alcohol use. Monthly clinical evaluation and liver function tests should be performed. Instruct patients 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. 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 The drug should be restarted in very small and gradually increasing doses and should be withdrawn immediately if there is any indication of recurrent liver involvement.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 .
Uses for IsonaRif
Rifampin and isoniazid combination is used to treat tuberculosis (TB) infection. It may be taken alone or with one or more other medicines for TB. Rifampin belongs to the class of medicines called antibiotics and works to kill or prevent the growth of bacteria. However, it will not work for colds, flu, or other virus infections.
This medicine is available only with your doctor's prescription.
Before using IsonaRif
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 this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine 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.
Appropriate studies have not been performed on the relationship of age to the effects of rifampin and isoniazid combination in children younger than 15 years of age. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of rifampin and isoniazid combination in the elderly.
Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.
Interactions with 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 this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine 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.
- Tenofovir Alafenamide
Using this medicine 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.
- Abiraterone Acetate
- Cholera Vaccine, Live
- Dabigatran Etexilate
- Doxorubicin Hydrochloride Liposome
- Ethinyl Estradiol
- Irinotecan Liposome
- Mycophenolate Mofetil
- Mycophenolic Acid
- Sirolimus Protein-Bound
- Vincristine Sulfate Liposome
Using this medicine 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.
- Aminosalicylic Acid
- Aripiprazole Lauroxil
- Enalapril Maleate
- Morphine Sulfate Liposome
- Valproic Acid
Interactions with Food/Tobacco/Alcohol
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. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine 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 this medicine, or give you special instructions about the use of food, alcohol, or tobacco.
Using this medicine 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 this medicine, or give you special instructions about the use of food, alcohol, or tobacco.
- Tyramine Containing Food
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Alcohol abuse, or history of—Use with caution. There may be an increased chance of getting liver problems if you take this medicine and drink alcohol daily.
- Blood clotting problems or
- Diabetes, history of or
- Porphyria (an enzyme problem) or
- Seizures or
- Vitamin K deficiency—Use with caution. May make these conditions worse.
- Gout, acute or
- Liver disease, acute or severe or
- Meningococcal disease (including infections of the lining of the brain and spinal cord [meningitis] and blood stream [eg, bacteremia, septicemia])—Should not be used in patients with these conditions.
- Kidney disease, severe—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
- Liver disease, chronic or
- Patients with poor nutrition status—Use with caution. May increase risk for vitamin K deficiency, which may lead to excessive bleeding.
Proper use of IsonaRif
Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects.
This medicine should be taken on an empty stomach, 1 hour before or 2 hours after a meal, with a full of glass of water. It is important to take this medicine on a regular schedule.
If this medicine upsets your stomach, take it with food. Antacids may also help. However, do not take aluminum-containing antacids (eg, Maalox®, Mylanta®) within 1 hour of the time you take rifampin and isoniazid combination. They may keep this medicine from working properly.
To help clear up your tuberculosis (TB) infection 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. It is important that you do not miss any doses.
Your doctor may also want you to take pyridoxine (eg, Hexa-Betalin, vitamin B6) 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 everyday along with this medicine. Do not miss any doses.
If you are taking itraconazole, do not use rifampin and isoniazid combination 2 weeks before and during itraconazole treatment.
The dose of this medicine 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 this medicine. 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.
- For the oral dosage form (capsules):
- For the treatment of tuberculosis:
- Adults and children 15 years of age and older weighing 55 kilograms (kg)—2 capsules (containing 600 milligrams (mg) of rifampin and 300 mg of isoniazid) once a day.
- Children younger than 15 years of age—Use and dose must be determined by your doctor.
- For the treatment of tuberculosis:
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.
If rifampin and isoniazid combination is taken on an irregular schedule, side effects may occur more often and may be more serious than usual. If you have any questions about this, check with your doctor.
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.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions while using IsonaRif
It is very important that your doctor check your or your child's progress at regular visits. Blood and urine tests may be needed to check for unwanted effects.
If your or your child's symptoms do not improve within 2 to 3 weeks, or if they become worse, check with your doctor.
Do not use this medicine if you are also receiving certain medicines to treat HIV infection (eg, atazanavir, darunavir, fosamprenavir, ritonavir, saquinavir, tipranavir, Aptivus®, Fortovase®, Invirase®, Lexiva®, Norvir®, Prezista®, or Reyataz®).
Do not use this medicine together with praziquantel. If you need to take praziquantel, you should stop using this medicine 4 weeks before starting praziquantel. You may restart this medicine one day after the last dose of praziquantel.
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 this medicine.
Check with your doctor right away if you or your child have a fever, chills, cough, sore throat, swollen, painful, or tender lymph glands in the neck, armpit, or groin, or yellow skin or eyes while using this medicine. These could be symptoms of a serious condition called drug reaction with eosinophilia and systemic symptoms (DRESS).
Serious skin reactions can occur with this medicine. Check with your doctor right away if you or your child have blistering, peeling, or loosening of the skin, red skin lesions, severe acne or a skin rash, sores or ulcers on the skin, or fever or chills with this medicine.
Check with your doctor right away if blurred vision, difficulty in reading, or any other change in vision occurs during or after treatment. Your doctor may want you or your child to have your eyes checked by an ophthalmologist (eye doctor).
Do not stop using this medicine suddenly without asking your doctor. You may need to slowly decrease your dose before stopping it completely.
Check with your doctor right away if you have joint pain, stiffness, or swelling, lower back, side, or stomach pain, or swelling of the feet or lower legs. These could be symptoms of an acute gout.
This medicine will cause urine, stool, saliva, sputum, sweat, teeth, and tears to turn reddish-orange to reddish-brown. This is to be expected while you are using this medicine. This effect may cause soft contact lenses to become permanently discolored. Standard cleaning solutions may not take out all the discoloration. It is best not to wear soft contact lenses while using this medicine. Hard contact lenses are not discolored by this medicine. This condition will return to normal once you stop using this medicine. If you have any questions about this, check with your doctor.
Check with your doctor right away if you feel very tired or very weak, or if you have clumsiness, unsteadiness, loss of appetite, nausea, numbness, tingling, burning, or pain in the hands and feet, or vomiting. 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.
Before you have any medical tests, tell the medical doctor in charge that you are using this medicine. The results of some tests may be affected by this medicine.
Eating certain foods (eg, Cheshire cheese, Swiss cheese, skipjack, tuna, or Sardinella) or drinking red wine may cause reactions in some patients taking isoniazid-containing medicines. Check with your doctor if flushing, fast or pounding heartbeat, headache, red or itching skin, sweating, dizziness, or lightheadedness occur while you are taking this medicine.
Birth control pills may not work properly while you are using this medicine. To keep from getting pregnant, use another form of birth control along with your birth control pills. Other forms include condoms, diaphragms, or contraceptive foams or jellies.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Side Effects of IsonaRif
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:
- Clumsiness or unsteadiness
- dark urine
- loss of appetite
- nausea and vomiting
- numbness, tingling, burning, or pain in the hands and feet
- unusual tiredness or weakness
- yellow eyes or skin
- difficult breathing
- itching, skin rash and redness
- muscle and bone pain
- Bloody or cloudy urine
- blurred vision or loss of vision, with or without eye pain
- convulsions (seizures)
- greatly decreased frequency of urination or amount of urine
- mood or mental changes
- sore throat
- unusual bleeding or bruising
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:
- stomach pain or upset
- Sore mouth or tongue
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.
More about IsonaRif (isoniazid / rifampin)
- Check interactions
- Compare alternatives
- Drug images
- Side effects
- Dosage information
- During pregnancy
- Drug class: antituberculosis combinations
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