Isoniazid has rarely caused very serious (possibly fatal) liver disease. The risk of liver disease is increased in people who are 35 years and older, who use alcohol or illegal injection drugs, or who currently have long-term liver problems. Tell your doctor right away if you develop symptoms of liver disease, including persistent nausea/vomiting, severe stomach/abdominal pain, unusual weakness/tiredness, dark urine, yellowing eyes/skin.
Your doctor should order liver function tests while you are taking this medication. Keep all medical and laboratory appointments.Who should not take Rifamate?
This product is used to treat tuberculosis (TB). It contains 2 medications: rifampin and isoniazid. Both medications are antibiotics. Rifampin is known as a rifamycin antibiotic. This product works by stopping the growth of bacteria.
This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.
Take this product by mouth 1 hour before or 2 hours after a meal, usually once daily or as directed by your doctor.
If you also take antacids, take this medication at least 1 hour before the antacid.
The dosage is based on your age, weight, medical condition, and response to treatment.
Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals. To help you remember, take it at the same time each day.
Continue to take this medication (and other TB medications) until the full prescribed amount is finished, even if symptoms disappear. Stopping the medication too early or skipping doses may allow the bacteria to continue to grow, which may result in a return of the infection and cause the infection to be more difficult to treat (resistant).
Your doctor may also direct you to take vitamin B6 (pyridoxine) to help prevent certain side effects (such as nerve problems) from isoniazid. Follow your doctor's instructions carefully.
Isoniazid may interact with foods containing tyramine/histamine (such as cheese, red wine, certain types of fish). This interaction may cause increased blood pressure, flushing of the skin, headache, dizziness, or fast/pounding heartbeat. Tell your doctor right away if any of these symptoms occur. Your doctor may recommend that you follow a special diet while taking this medication. Consult your doctor for more details.
Tell your doctor if your condition persists or worsens.
See also Warning section.
Nausea/vomiting, upset stomach, heartburn, or headache may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
This medication may cause urine, sweat, saliva, or tears to turn reddish. This effect is harmless and will disappear when the medication is stopped. However, dentures and contact lenses may become permanently stained.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if any of these unlikely but serious side effects occur: numbness/tingling of arms/legs, painful/swollen joints.
Tell your doctor right away if any of these rare but serious side effects occur: change in the amount of urine, increased thirst/urination, bloody urine, vision changes, easy bruising/bleeding, signs of a new infection (such as fever, persistent sore throat), mental/mood changes (such as confusion, psychosis), seizures.
This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea products or narcotic pain medications if you have any of the following symptoms because these products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
See also Warning section.
Before taking this product, tell your doctor or pharmacist if you are allergic to rifampin or isoniazid; or to other rifamycins (such as rifabutin, rifapentine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: previous severe reaction from isoniazid (such as liver disease), liver disease, kidney disease, alcohol use, HIV infection, diabetes, numbness/tingling of arms/legs (peripheral neuropathy), recent childbirth, a certain blood disorder (porphyria).
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Alcohol may increase the risk of liver disease. Avoid alcoholic beverages while using this medication.
This product may cause live bacterial vaccines (such as typhoid vaccine) not to work as well. Therefore, do not have any immunizations/vaccinations while using this medication without the consent of your doctor.
During pregnancy, this product should be used only when clearly needed. When rifampin is taken during the last few weeks of pregnancy, the risk of bleeding in both mother and infant may be increased. Tell your doctor right away if you notice any bleeding in your newborn. Discuss the risks and benefits with your doctor.
This product passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.
See also How to Use section.
The effects of some drugs can change if you take other drugs or herbal products at the same time. This can increase your risk for serious side effects or may cause your medications not to work correctly. These drug interactions are possible, but do not always occur. Your doctor or pharmacist can often prevent or manage interactions by changing how you use your medications or by close monitoring.
To help your doctor and pharmacist give you the best care, be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before starting treatment with this product. While using this product, do not start, stop, or change the dosage of any other medicines you are using without your doctor's approval.
Some products that may interact with this drug include: acetaminophen, carbamazepine, disulfiram, MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, tranylcypromine), SSRI antidepressants (such as fluoxetine, sertraline), valproic acid.
Rifampin can speed up the removal of other medications from your body, which may affect how they work. Examples of affected drugs include cyclosporine, digoxin, nimodipine, phenytoin, ranolazine, tacrolimus, theophylline, certain anti-infectives (e.g., chloramphenicol, clarithromycin, dapsone, doxycycline, linezolid, telithromycin, zidovudine, quinolones such as ciprofloxacin) azole antifungals (such as itraconazole, ketoconazole), "blood thinners" (such as warfarin), calcium channel blockers (such as diltiazem, verapamil), HIV NNRTIs (such as delavirdine, etravirine, nevirapine), HIV protease inhibitors (such as atazanavir, ritonavir, saquinavir), among others.
This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Discuss with your doctor or pharmacist if you should use additional reliable birth control methods while using this medication. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well.
This medication may interfere with certain laboratory tests (including folate/vitamin B12 levels, urine glucose tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
This document does not contain all possible interactions. Keep a list of all the products you use. Share this list with your doctor and pharmacist to lessen your risk for serious medication problems.
If overdose is suspected, contact a poison control center or emergency room right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe stomach/abdominal pain, unusual tiredness/weakness, yellowing eyes/skin, vision changes, slow/shallow breathing, severe drowsiness.
Do not share this medication with others.
Laboratory and/or medical tests (such as sputum test, kidney/liver function, bilirubin levels, complete blood count) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
For the best possible benefit, it is important to take each scheduled dose of this medication as directed. If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Store at room temperature away from light and moisture. Check the product package for the exact temperature range, or ask your pharmacist. Do not store in the bathroom. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised March 2013. Copyright(c) 2013 First Databank, Inc.
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