RIFAMPIN- rifampin capsule
Lupin Pharmaceuticals, Inc.
Rx only
To reduce the development of drug-resistant bacteria and maintain the effectiveness of rifampin capsules USP and other antibacterial drugs, rifampin should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.
DESCRIPTION
Rifampin capsules USP for oral administration contain 150 mg or 300 mg rifampin per capsule. The 150 mg and 300 mg capsules also contain, as inactive ingredients: corn starch, crospovidone, D & C Red no. 28, FD & C Blue no. 1, FD & C Red no. 40, gelatin, magnesium stearate, potassium hydroxide, pregelatinized starch, propylene glycol, shellac, sodium lauryl sulphate and titanium dioxide.
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 C43 H58 N4 O12 . 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-2,4,12,16,20,22�heptamethyl-8-[N-(4-methyl-1-piperazinyl)formimidoyl]-2,7-(epoxypentadeca[1,11,13]trienimino)naphtho[2,1-b ]furan-1,11(2H)-dione 21-acetate.
Its structural formula is:
rifampin
(click image for full-size original)
CLINICAL PHARMACOLOGY
Oral Administration
Rifampin is readily absorbed from the gastrointestinal tract. Peak serum concentrations in healthy adults and pediatric populations vary widely from individual to individual. Following a single 600 mg oral dose of rifampin in healthy adults, the peak serum concentration averages 7 mcg/mL but may vary from 4 to 32 mcg/mL. Absorption of rifampin is reduced by about 30% when the drug is ingested with food.
Rifampin is widely distributed throughout the body. It is present in effective concentrations in many organs and body fluids, including cerebrospinal fluid. Rifampin is about 80% protein bound. Most of the unbound fraction is not ionized and, therefore, diffuses freely into tissues.
Microbiology
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.
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.
DOSAGE AND ADMINISTRATION
Rifampin can be administered by the oral route (see INDICATIONS AND USAGE ). See CLINICAL PHARMACOLOGY for dosing information in patients with renal failure.
Tuberculosis
Adults
10 mg/kg, in a single daily administration, not to exceed 600 mg/day, oral
Pediatric Patients
10-20 mg/kg, not to exceed 600 mg/day, oral
It is recommended that oral rifampin be administered once daily, either 1 hour before or 2 hours after a meal with a full glass of water.
