Rifampin
RIFADIN
What it isInhibitor of bacterial RNA polymerase; tuberculosis, staphylococcal prosthetic infection and meningococcal prophylaxis.
Why this oneIt penetrates biofilm and intracellular sites that other agents cannot reach, which is why it is added in prosthetic infection.
What limits it⚑ Its potent enzyme induction can defeat contraceptives, anticoagulants, and transplant drugs. Orange body fluids and hepatotoxicity are expected.
FDA-approved for
- tuberculosis (1971)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Tuberculosis (all forms) | adult | 10 mg/kg QD | 10 mg/kg QD | 600 mg/day |
| Tuberculosis (all forms) | pediatric | 10-20 mg/kg QD | 10-20 mg/kg QD | 600 mg/day |
| Meningococcal carriers | adult | 600 mg BID x2 days | 600 mg BID x2 days | 600 mg/dose |
| Meningococcal carriers | pediatric ≥1 mo | 10 mg/kg q12h x2 days | 10 mg/kg q12h x2 days | 600 mg/dose |
| Meningococcal carriers | pediatric <1 mo | 5 mg/kg q12h x2 days | 5 mg/kg q12h x2 days |
Renal Undefined (label refers to Clinical Pharmacology for renal-failure dosing; no explicit adjustment given)
Hepatic Undefined
Instructions
- Take 1 hour before or 2 hours after a meal with a full glass of water
- Extemporaneous 10 mg/mL oral suspension may be compounded for patients who cannot swallow capsules
Contraindications
- Ritonavir-boosted saquinavir (risk of severe hepatocellular toxicity)
- Atazanavir, darunavir, fosamprenavir, saquinavir, tipranavir, cabotegravir, fostemsavir, lenacapavir (markedly decreased antiviral levels)
- Praziquantel (subtherapeutic praziquantel levels)
- Lurasidone (strong CYP3A4 induction lowers lurasidone exposure)
Cautions
- Hepatotoxicity (transient LFT abnormalities, hepatitis); monitor
- Thrombocytopenia/purpura — discontinue if purpura occurs (cerebral hemorrhage reported on continuation)
- Hypersensitivity reactions incl. DRESS, SJS, TEN, anaphylaxis
- 'Flu syndrome' and hypersensitivity with intermittent/interrupted dosing
- C. difficile-associated diarrhea
- Potent CYP450 enzyme induction — many drug interactions
- Red-orange discoloration of body fluids; permanent tooth discoloration
Adverse reactions
- Nausea/vomiting, diarrhea, cramps
- Hepatotoxicity
- Thrombocytopenia
- Flu syndrome
- Rash/pruritus
- Discolored body fluids
Pregnancy Use only if benefit outweighs risk; late-pregnancy use may cause postnatal hemorrhage in mother and infant (vitamin K may be indicated)
Lactation Undefined
NO BOXED WARNINGS
Principal riskThe most powerful enzyme inducer in clinical use
Cost, est. cash$10–$300/month
Generic entry1997
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityPowerful enzyme induction lowers many drug exposures; hepatotoxicity and body-fluid discoloration occur.
Mechanism of action: Rifampin ballicule
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