Rifamate

(Isoniazid/Rifampacin)

The active ingredients in Rifamate are rifampin and isoniazid. Rifamate is a combination of rifampicin and isoniazid used to treat tuberculosis. Rifampicin works by inhibiting bacterial RNA synthesis through blocking DNA-dependent RNA polymerase, which stops protein production in Mycobacterium tuberculosis. Isoniazid inhibits the synthesis of mycolic acids, essential components of the mycobacterial cell wall. Together, they kill actively dividing bacteria and prevent resistance, making the treatment more effective.

Follow all directions given to you by your doctor and read all documents provided, including the full Prescribing Information, FDA-Approved Product Labeling, Instructions for Use, and Medication Guide before using Rifamate. However, the following is a synopsis of the general guidelines for the use of Rifamate:

• Rifamate is taken by mouth on an empty stomach, either 1 hour before or 2 hours after meals.
• It should be taken with a full glass of water.
• The medication is usually taken once daily.
• Rifamate should be taken exactly as prescribed for the full course of treatment, even if symptoms improve.
• Pyridoxine (vitamin B6) may be prescribed to reduce the risk of nerve problems caused by isoniazid.
• Regular blood tests are required to monitor liver function and other laboratory values.
• Soft contact lenses may be permanently stained.

Some mild or common side effects of rifampin include:

• Loss of appetite.
• Stomach pain or heartburn.
• Dizziness.
• Mild skin rash.
• Orange or reddish discoloration of urine, sweat, saliva, or tears.

Some individuals may experience serious side effects while using Rifamate. These side effects may require immediate medical attention. If you experience any of the following, contact your healthcare provider or seek emergency medical help:

• Signs of liver disease or hepatitis, such as dark urine, elevated liver enzymes, yellowing of the skin or eyes, or severe fatigue.
• Severe hypersensitivity reactions, including fever and skin peeling.
• Unusual bleeding or bruising.
• Numbness or tingling in the hands or feet.

These are not all of the possible adverse reactions of Rifamate. You should always seek medical advice from your healthcare provider for any questions or concerns about your medical condition or treatment. Read all patient information, medication guides, or drug information sheets that come with this medication. You can also report adverse effects to the Food and Drug Administration at www.fda.gov/medwatch or 1-800-FDA-1088.

Before starting Rifamate, it is crucial to discuss any existing health conditions with your healthcare provider. You should be sure that your healthcare provider is aware of all your medical conditions, including if you have:

• Liver disease or a history of hepatitis.
• Alcohol use disorder.
• Kidney disease.
• Diabetes.
• HIV infection.
• A history of hypersensitivity reactions.
• Peripheral neuropathy.
• Pregnancy or breastfeeding plans.
• Birth control pills may not work properly while you are using this medicine.
• Concomitant antacid administration may reduce the absorption of rifampin.
• Rifamate can cause serious liver toxicity, especially when combined with other hepatotoxic agents or alcohol.

Boxed Warning

Rifamate has a boxed warning for hepatotoxicity.

Severe and sometimes fatal liver injury has been reported with rifampin and isoniazid. The risk is higher in patients with liver disease, those who drink alcohol daily, and older adults. Liver function tests should be performed before treatment and monitored regularly during therapy.

Rifamate should not be used in patients who:

• Have severe liver disease.
• Have a history of hypersensitivity to rifampin, isoniazid, or other rifamycins.
• Are receiving ritonavir-boosted saquinavir.
• Are taking certain medications that strongly interact with rifampin and cannot be adjusted.

Rifamate begins working shortly after treatment starts, but tuberculosis treatment requires several months to fully clear the infection. Symptoms may improve within weeks, but treatment must continue as prescribed.

When Rifamate is taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the frequency or severity of side effects. Make sure that you tell your healthcare professional about anything that you are taking to avoid any negative drug interactions, including:

• Atazanavir, darunavir, saquinavir, fosamprenavir, and tipranavir may have reduced plasma concentrations.
• Warfarin, which may have reduced the anticoagulant effect.
• Hormonal contraceptives may be less effective due to enzyme induction.
• Ketoconazole, itraconazole, and fluconazole may have reduced antifungal activity.
• Cyclosporine and tacrolimus, which may have reduced immunosuppressive levels.
• Phenytoin, which may have altered blood levels.
• Zidovudine, which may have reduced antiviral effectiveness.
• Methadone, which may have reduced therapeutic effect.
• Verapamil, diltiazem, nifedipine, quinine, and quinidine.
• Clarithromycin.
• Dapsone.
• Diazepam.
• Praziquantel.
• Theophylline.
• Digoxin.
• Levothyroxine.
• Haloperidol.
• Enalapril.
• Tyramine.
• Pyrazinamide.
• Disopyramide.

Rifamate is available as an oral capsule containing fixed doses of rifampin and isoniazid. Dosing is determined by the healthcare provider based on treatment phase and patient factors.

It should be stored at room temperature, away from the reach of children or pets.

Rifamate is manufactured by companies approved by the Food and Drug Administration.

Yes. Generic versions containing rifampin and isoniazid are available.

Do not stop taking Rifamate without medical advice. Stopping treatment early may cause treatment failure or drug resistance. Your healthcare provider will guide safe discontinuation.

When given during the last few weeks of pregnancy, rifampin can cause hemorrhages in the mother and infant, for which treatment with vitamin K may be needed. Rifamate should only be used during pregnancy if the possible benefits outweigh the potential risk to the unborn baby.

You should not take Rifamate if you are breastfeeding. Talk to your provider if you plan on breastfeeding.