Rifampicin (Rifampin)

Rifadin, Rimactane, Rifampin

Antimycobacterial • Rifamycin antibiotic

Premium

Hepatotoxic

Half-life

3-4 hours

Protein Binding

80%

Metabolized By

CYP3A4

External

Drugs.com

Boxed warning

Hepatotoxicity — monitor liver function tests

Clinical alerts

Boxed warning

1 boxed warning

Hepatotoxic

Monitor liver function

Mechanism of action

Inhibits bacterial DNA-dependent RNA polymerase; one of the most potent CYP enzyme inducers known

Interactions

17 curated · 12 major or contraindicated · select a row for management

Interacting drug	Severity	Effect
alprazolam	major	Marked reduction in anxiolytic effect; risk of benzodiazepine withdrawal in chronic users.
apixaban	major	Substantially reduced anticoagulant effect; increased thromboembolic risk.
atorvastatin	major	Marked reduction in statin efficacy; loss of lipid-lowering effect.
fluconazole	major	Reduced antifungal efficacy; risk of treatment failure for fungal infections.
imatinib	major	Loss of tyrosine kinase inhibition; risk of cancer progression.
isoniazid	major	Increased risk of drug-induced hepatitis, particularly in slow acetylators, elderly, and patients with pre-existing liver disease.
oxycodone	major	Near-complete loss of opioid analgesia; risk of uncontrolled pain and potential opioid withdrawal in dependent patients.
phenytoin	major	Sub-therapeutic phenytoin levels; increased seizure risk.
quetiapine	major	Loss of antipsychotic efficacy; risk of psychotic relapse.
sildenafil	major	Near-complete loss of PDE5 inhibitor efficacy (both for erectile dysfunction and pulmonary hypertension indications).
simvastatin	major	Near-complete loss of statin efficacy; LDL cholesterol control lost.
warfarin	major	Profound reduction in warfarin anticoagulant effect; INR may drop to sub-therapeutic levels within days, leading to thromboembolic risk.
acetaminophen	moderate	Increased risk of hepatotoxicity, especially at higher acetaminophen doses. Reduced analgesic/antipyretic effectiveness due to accelerated clearance.
carbamazepine	moderate	Reduced carbamazepine levels; increased seizure risk.
digoxin	moderate	Reduced digoxin levels; risk of loss of rate/rhythm control.
levothyroxine	moderate	Decreased levothyroxine levels; hypothyroidism may develop or worsen.
metformin	minor	Modest change in metformin exposure; generally not clinically significant.

Common adverse effects

Orange/red discoloration of urine, tears, sweat
Nausea
Hepatitis
Flu-like syndrome
Thrombocytopenia

Food, alcohol & herbal

Food

Take on empty stomach (1 hour before or 2 hours after meals)
Food decreases absorption by ~30%
Avoid tyramine-rich foods in combination with isoniazid co-therapy

Alcohol · major

Increased hepatotoxicity risk; alcohol accelerates rifampicin metabolism and increases liver damage potential

Herbal

St. John's Wort (moderate) — Additive CYP induction — may further reduce levels of co-administered drugs
Kava (major) — Additive hepatotoxicity risk
Milk thistle (minor) — May modestly inhibit CYP enzymes, partially counteracting rifampicin induction

Pharmacokinetics

Half-life: 3-4 hours
Protein binding: 80%
Metabolised by: CYP3A4
Induces: CYP3A4, CYP2C9, CYP2C19, CYP1A2, CYP2B6, CYP2C8

Pregnancy & lactation

Not recorded for Rifampicin (Rifampin). Absence here means this database does not hold a category — not that the drug is safe in pregnancy or breastfeeding.

Sources

Assembled from: drug index, curated drug database, curated interaction pairs.

Not a substitute for clinical judgement

Rifampicin (Rifampin)

Rifadin, Rimactane, Rifampin

Antimycobacterial • Rifamycin antibiotic

Premium

Hepatotoxic

Half-life

3-4 hours

Protein Binding

80%

Metabolized By

CYP3A4

External

Drugs.com

Boxed warning

Hepatotoxicity — monitor liver function tests

Clinical alerts

Boxed warning

1 boxed warning

Hepatotoxic

Monitor liver function

Mechanism of action

Inhibits bacterial DNA-dependent RNA polymerase; one of the most potent CYP enzyme inducers known

Interactions

17 curated · 12 major or contraindicated · select a row for management

Interacting drug	Severity	Effect
alprazolam	major	Marked reduction in anxiolytic effect; risk of benzodiazepine withdrawal in chronic users.
apixaban	major	Substantially reduced anticoagulant effect; increased thromboembolic risk.
atorvastatin	major	Marked reduction in statin efficacy; loss of lipid-lowering effect.
fluconazole	major	Reduced antifungal efficacy; risk of treatment failure for fungal infections.
imatinib	major	Loss of tyrosine kinase inhibition; risk of cancer progression.
isoniazid	major	Increased risk of drug-induced hepatitis, particularly in slow acetylators, elderly, and patients with pre-existing liver disease.
oxycodone	major	Near-complete loss of opioid analgesia; risk of uncontrolled pain and potential opioid withdrawal in dependent patients.
phenytoin	major	Sub-therapeutic phenytoin levels; increased seizure risk.
quetiapine	major	Loss of antipsychotic efficacy; risk of psychotic relapse.
sildenafil	major	Near-complete loss of PDE5 inhibitor efficacy (both for erectile dysfunction and pulmonary hypertension indications).
simvastatin	major	Near-complete loss of statin efficacy; LDL cholesterol control lost.
warfarin	major	Profound reduction in warfarin anticoagulant effect; INR may drop to sub-therapeutic levels within days, leading to thromboembolic risk.
acetaminophen	moderate	Increased risk of hepatotoxicity, especially at higher acetaminophen doses. Reduced analgesic/antipyretic effectiveness due to accelerated clearance.
carbamazepine	moderate	Reduced carbamazepine levels; increased seizure risk.
digoxin	moderate	Reduced digoxin levels; risk of loss of rate/rhythm control.
levothyroxine	moderate	Decreased levothyroxine levels; hypothyroidism may develop or worsen.
metformin	minor	Modest change in metformin exposure; generally not clinically significant.

Common adverse effects

Orange/red discoloration of urine, tears, sweat
Nausea
Hepatitis
Flu-like syndrome
Thrombocytopenia

Food, alcohol & herbal

Food

Take on empty stomach (1 hour before or 2 hours after meals)
Food decreases absorption by ~30%
Avoid tyramine-rich foods in combination with isoniazid co-therapy

Alcohol · major

Increased hepatotoxicity risk; alcohol accelerates rifampicin metabolism and increases liver damage potential

Herbal

St. John's Wort (moderate) — Additive CYP induction — may further reduce levels of co-administered drugs
Kava (major) — Additive hepatotoxicity risk
Milk thistle (minor) — May modestly inhibit CYP enzymes, partially counteracting rifampicin induction

Pharmacokinetics

Half-life: 3-4 hours
Protein binding: 80%
Metabolised by: CYP3A4
Induces: CYP3A4, CYP2C9, CYP2C19, CYP1A2, CYP2B6, CYP2C8

Pregnancy & lactation

Not recorded for Rifampicin (Rifampin). Absence here means this database does not hold a category — not that the drug is safe in pregnancy or breastfeeding.

Sources

Assembled from: drug index, curated drug database, curated interaction pairs.

Not a substitute for clinical judgement

Rifampicin (Rifampin) Drug Profile | PharmaGraphX