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Quick facts
- Drug class
- Rifamycin Antibacterial [EPC]
- How it is given
- intravenous
- Type
- human prescription drug
- Brand names
- Rifadin IV
- RxNorm ID
- 207436
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
INDICATIONS AND USAGE In the treatment of both tuberculosis and the meningococcal carrier state, the small number of resistant cells present within large populations of susceptible cells can rapidly become the predominant type. Bacteriologic cultures should be obtained before the start of therapy to confirm the susceptibility of the organism to rifampin and they should be repeated throughout therapy to monitor the response to treatment. Since resistance can emerge rapidly, susceptibility tests should be performed in the event of persistent positive cultures during the course of treatment. If test results show resistance to rifampin and the patient is not responding to therapy, the drug regimen should be modified. Tuberculosis Rifampin is indicated in the treatment of all forms of tuberculosis. A three-drug regimen consisting of rifampin, isoniazid, and pyrazinamide is recommended in the initial phase of short-course therapy which is usually continued for 2 months. The Advisory Council for the Elimination of Tuberculosis, the American Thoracic Society, and Centers for Disease Control and Prevention recommend that either streptomycin or ethambutol be added as a fourth drug in a regimen containing isoniazid (INH), rifampin, and pyrazinamide for initial treatment of tuberculosis unless the likelihood of INH resistance is very low. The need for a fourth drug should be reassessed when the results of susceptibility testing are known. If community rates of INH resistance are currently less than 4%, an initial treatment regimen with less than four drugs may be considered. Following the initial phase, treatment should be continued with rifampin and isoniazid for at least 4 months. Treatment should be continued for longer if the patient is still sputum or culture positive, if resistant organisms are present, or if the patient is HIV positive. RIFADIN IV is indicated for the initial treatment and retreatment of tuberculosis when the drug cannot be taken by mouth. Meningococcal Carriers Rifampin is indicated for the treatment of asymptomatic carriers of Neisseria meningitidis to eliminate meningococci from the nasopharynx. […]
About this medicine
DESCRIPTION RIFADIN (rifampin capsules USP) for oral administration contains 150 mg or 300 mg rifampin per capsule. The 150 mg and 300 mg capsules also contain, as inactive ingredients: corn starch, D&C Red No. 28, FD&C Blue No. 1, FD&C Red No. 40, gelatin, magnesium stearate, and titanium dioxide. RIFADIN IV (rifampin for injection USP) contains rifampin 600 mg, sodium formaldehyde sulfoxylate 10 mg, and sodium hydroxide to adjust pH. Rifampin is a semisynthetic antibiotic derivative of rifamycin SV. Rifampin is a red-brown crystalline powder very slightly soluble in water at neutral pH, freely soluble in chloroform, soluble in ethyl acetate and in methanol. Its molecular weight is 822.95 and its chemical formula is C 43 H 58 N 4 O 12 . The chemical name for rifampin is either: 3-[[(4-Methyl-1-piperazinyl)imino]methyl]rifamycin or 5,6,9,17,19,21-hexahydroxy-23-methoxy-2,4,12,16,18,20,22– heptamethyl-8-[ N -(4-methyl-1-piperazinyl)formimidoyl]-2,7-(epoxypentadeca [1,11,13]trienimino)naphtho[2,1- b ]furan-1,11(2 H )-dione 21-acetate. Its structural formula is: Chemical Structure
How it works
Mechanism of Action Rifampin inhibits DNA-dependent RNA polymerase activity in susceptible Mycobacterium tuberculosis organisms. Specifically, it interacts with bacterial RNA polymerase but does not inhibit the mammalian enzyme.
Who should not take it
CONTRAINDICATIONS RIFADIN is contraindicated in patients with a history of hypersensitivity to rifampin or any of the components, or to any of the rifamycins. (See WARNINGS .) Rifampin is contraindicated in patients who are also receiving ritonavir-boosted saquinavir due to an increased risk of severe hepatocellular toxicity. (See PRECAUTIONS, Drug Interactions .) Rifampin is contraindicated in patients who are also receiving atazanavir, darunavir, fosamprenavir, saquinavir, tipranavir, cabotegravir, fostemsavir and lenacapavir (see prescribing information for SUNLENCA ® ) due to the potential of rifampin to substantially decrease plasma concentrations of these antiviral drugs, which may result in decreased antiviral efficacy and/or development of viral resistance. (See PRECAUTIONS, Drug Interactions .) Rifampin is contraindicated in patients receiving praziquantel since therapeutically effective blood levels of praziquantel may not be achieved. In patients receiving rifampin who need immediate treatment with praziquantel alternative agents should be considered. However, if treatment with praziquantel is necessary, rifampin should be discontinued 4 weeks before administration of praziquantel. Treatment with rifampin can then be restarted one day after completion of praziquantel treatment. Rifampin is contraindicated in patients receiving lurasidone. Concomitant use of lurasidone with strong CYP3A4 inducers (e.g., rifampin) decreased the exposure of lurasidone compared to the use of lurasidone alone. (See PRECAUTIONS, Drug Interactions ).
Warnings
WARNINGS Hepatotoxicity of hepatocellular, cholestatic, and mixed patterns has been reported in patients treated with rifampin. Severity ranged from asymptomatic elevations in liver enzymes, isolated jaundice/hyperbilirubinemia, symptomatic self-limited hepatitis to fulminant liver failure and death. Severe hepatic dysfunction including fatalities were reported in patients with liver disease and in patients taking rifampin with other hepatotoxic agents. Monitor for symptoms and clinical/laboratory signs of liver injury, especially if treatment is prolonged or given with other hepatotoxic drugs. Patients with impaired liver function should be given rifampin only in cases of necessity and then under strict medical supervision. In these patients, careful monitoring of liver function should be done prior to therapy and then every 2 to 4 weeks during therapy. If signs of hepatic damage occur or worsen, discontinue rifampin. Rifampin has enzyme-inducing properties, including induction of delta amino levulinic acid synthetase. Isolated reports have associated porphyria exacerbation with rifampin administration. The possibility of rapid emergence of resistant meningococci restricts the use of RIFADIN to short-term treatment of the asymptomatic carrier state. RIFADIN is not to be used for the treatment of meningococcal disease. Systemic hypersensitivity reactions were reported with RIFADIN administration. Signs and symptoms of hypersensitivity reactions may include fever, rash, urticaria, angioedema, hypotension, acute bronchospasm, conjunctivitis, thrombocytopenia, neutropenia, elevated liver transaminases or flu-like syndrome (weakness, fatigue, muscle pain, nausea, vomiting, headache, chills, aches, itching, sweats, dizziness, shortness of breath, chest pain, cough, syncope, palpitations). Manifestations of hypersensitivity, such as fever, lymphadenopathy or laboratory abnormalities (including eosinophilia, liver abnormalities) may be present even though rash is not evident. Monitor patients receiving RIFADIN for signs and/or symptoms of hypersensitivity reactions. If these signs or symptoms occur, discontinue RIFADIN and administer supportive measures. […]
Reported side effects
ADVERSE REACTIONS The following adverse reactions associated with the use of RIFADIN were identified in clinical studies or postmarketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Gastrointestinal Heartburn, epigastric distress, anorexia, nausea, vomiting, jaundice, flatulence, cramps, and diarrhea have been noted in some patients. Although Clostridium difficile has been shown in vitro to be sensitive to rifampin, pseudomembranous colitis has been reported with the use of rifampin (and other broad-spectrum antibiotics). Therefore, it is important to consider this diagnosis in patients who develop diarrhea in association with antibiotic use. Tooth discoloration (which may be permanent) may occur. Hepatic Hepatotoxicity including transient abnormalities in liver function tests (e.g., elevations in serum bilirubin, alkaline phosphatase, serum transaminases, gamma-glutamyl transferase), hepatitis, shock-like syndrome with hepatic involvement and abnormal liver function tests, and cholestasis have been reported (see WARNINGS ). Hematologic Cases of thrombotic microangiopathy, including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, have been reported (see WARNINGS ). Thrombocytopenia has occurred primarily with high dose intermittent therapy but has also been noted after resumption of interrupted treatment. It rarely occurs during well-supervised daily therapy. This effect is reversible if the drug is discontinued as soon as purpura occurs. Cerebral hemorrhage and fatalities have been reported when rifampin administration has been continued or resumed after the appearance of purpura. Rare reports of disseminated intravascular coagulation have been observed. Leukopenia, hemolytic anemia, decreased hemoglobin, bleeding, and vitamin K–dependent coagulation disorders (abnormal prolongation of prothrombin time or low vitamin K–dependent coagulation factors) have been observed. Agranulocytosis has been reported very rarely. […]
Interactions with other medicines
Drug Interactions Pharmacodynamic Interactions Healthy subjects who received rifampin 600 mg once daily concomitantly with saquinavir 1000 mg/ritonavir 100 mg twice daily (ritonavir-boosted saquinavir) developed severe hepatocellular toxicity. Therefore, concomitant use of these medications is contraindicated. (See CONTRAINDICATIONS .) When rifampin is given concomitantly with other hepatotoxic medications such as halothane or isoniazid, the potential for hepatotoxicity is increased. The concomitant use of rifampin and halothane should be avoided. Patients receiving both rifampin and isoniazid should be monitored closely for hepatotoxicity. Effect of Rifampin on Other Drugs Induction of Drug Metabolizing Enzymes and Transporters Drug metabolizing enzymes and transporters affected by rifampin include cytochromes P450 (CYP) 1A2, 2B6, 2C8, 2C9, 2C19, and 3A4, UDP-glucuronyltransferases (UGT), sulfotransferases, carboxylesterases, and transporters including P-glycoprotein (P-gp) and multidrug resistance-associated protein 2 (MRP2). Most drugs are substrates for one or more of these enzyme or transporter pathways and these pathways may be induced by rifampin simultaneously. Therefore, rifampin may increase the metabolism and decrease the activity of certain coadministered drugs or increase the activity of a coadministered pro-drug (where metabolic activation is required), and has the potential to perpetuate clinically important drug-drug interactions against many drugs and across many drug classes (Table 1). Table 1 summarizes the effect of rifampin on other drugs or drug classes. Adjust dosages of concomitant drugs based on approved drug labeling and if applicable, therapeutic drug monitoring, unless otherwise specified. […]
If too much is taken
OVERDOSAGE Signs and Symptoms Nausea, vomiting, abdominal pain, pruritus, headache, and increasing lethargy will probably occur within a short time after ingestion; unconsciousness may occur when there is severe hepatic disease. Transient increases in liver enzymes and/or bilirubin may occur. Brownish-red or orange discoloration of the skin, urine, sweat, saliva, tears, and feces will occur, and its intensity is proportional to the amount ingested. Liver enlargement, possibly with tenderness, can develop within a few hours after severe overdosage; bilirubin levels may increase and jaundice may develop rapidly. Hepatic involvement may be more marked in patients with prior impairment of hepatic function. Other physical findings remain essentially normal. A direct effect upon the hematopoietic system, electrolyte levels, or acid-base balance is unlikely. Facial or periorbital edema has also been reported in pediatric patients. Hypotension, sinus tachycardia, ventricular arrhythmias, seizures, and cardiac arrest were reported in some fatal cases. Acute Toxicity The minimum acute lethal or toxic dose is not well established. However, nonfatal acute overdoses in adults have been reported with doses ranging from 9 to 12 gm rifampin. Fatal acute overdoses in adults have been reported with doses ranging from 14 to 60 gm. Alcohol or a history of alcohol abuse was involved in some of the fatal and nonfatal reports. Nonfatal overdoses in pediatric patients ages 1 to 4 years old of 100 mg/kg for one to two doses has been reported. Treatment Intensive support measures should be instituted and individual symptoms treated as they arise. The airway should be secured and adequate respiratory exchange established. Since nausea and vomiting are likely to be present, gastric lavage within the first 2 to 3 hours after ingestion is probably preferable to induction of emesis. Following evacuation of the gastric contents, the instillation of activated charcoal slurry into the stomach may help absorb any remaining drug from the gastrointestinal tract. Antiemetic medication may be required to control severe nausea and vomiting. […]
Storing it safely
Storage: Store at 25°C (77°F); excursions permitted to 15–30°C (59–86°F) [see USP Controlled Room Temperature]. Avoid excessive heat (temperatures above 40°C or 104°F). Protect from light. Rx only
Before you take anything new
Tell your pharmacist or doctor about every medicine you take — including ones bought without a prescription, herbal products and supplements. Interactions are one of the most common avoidable causes of harm from medicines, and a pharmacist can check your full list in a couple of minutes.
This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 27 May 2026. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.