Antituberculosis agent (ansamycin; potent enzyme inducer)
Rifampicin is an antibiotic used mainly to treat tuberculosis, always in combination with other medicines. It is very effective, but speeds up the elimination of many other medicines, so it can reduce the effect of treatments you take at the same time.
Also known as: Rifadin, Rimactane
Rifampin accelerates Omeprazole metabolism and reduces its acid-suppressing effect.
Omeprazole is metabolised by CYP2C19 and CYP3A4; rifampicin induces these enzymes and can reduce its concentrations by more than 50%, decreasing gastric acid suppression (relevant in ulcer, severe GORD or stress prophylaxis). Monitor the clinical response and consider increasing the omeprazole dose or preferring a less affected PPI (e.g. pantoprazole) during the combination.
Omeprazole + rifampicin: rifampicin lowers omeprazole levels (CYP2C19/3A4 induction), reducing acid suppression. Monitor the response and consider adjustment.
CYP2C19 induction, the main Omeprazole metabolic pathway.
Symptom control (dyspepsia, GERD, ulcer).
Recurrent gastric symptoms.
Consider a higher dose or an alternative (e.g. a PPI less dependent on CYP2C19).
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Omeprazole label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=37291cab-e350-d8e3-e063-6294a90a9cb1
Rifampin (a CYP450 inducer) markedly reduces Ketoconazole levels, risking antifungal treatment failure.
The interaction is bidirectional: rifampicin induces CYP3A4 and markedly reduces ketoconazole concentrations (loss of antifungal effect), while ketoconazole inhibits CYP3A4 and can raise rifampicin levels, with risk of hepatotoxicity. The combination should be avoided; if unavoidable, monitor the antifungal response and liver function, considering antifungal alternatives not dependent on CYP3A4 (e.g. amphotericin B, echinocandins).
Ketoconazole + rifampicin: rifampicin lowers ketoconazole levels (antifungal failure) and ketoconazole raises rifampicin levels. Avoid the combination.
Enzymatic induction (CYP3A4/P-glycoprotein) by rifampin accelerates ketoconazole elimination and reduces its efficacy.
Clinical response to the antifungal; ketoconazole levels (if available); liver function tests.
Persistent or worsening fungal infection, recurrent fever.
Avoid the combination. If both are required, use an alternative antifungal and monitor clinical and mycological response.
DailyMed/FDA (NIH/NLM) — approved Ketoconazole label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f162e616-21b4-49b1-b437-15e21001a6f0 ; approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b — with additional reference: Prontuário Terapêutico do INFARMED, INFARMED (11th ed., 2012)
Rifampin reduces Fluconazole levels, risking antifungal treatment failure.
Rifampicin induces CYP2C9 and CYP3A4, pathways of fluconazole metabolism, and can reduce its concentrations by about 25–50% and shorten the half-life; the antifungal effect may be compromised in severe infections. Monitor the clinical response and consider increasing the fluconazole dose during the combination, monitoring liver function.
Fluconazole + rifampicin: rifampicin lowers fluconazole levels (~25–50%), potentially compromising antifungal treatment. Monitor and consider dose adjustment.
Enzymatic induction by rifampin accelerates fluconazole metabolism.
Clinical response, liver function tests.
Persistent or worsening fungal infection.
Monitor clinical response; a fluconazole dose increase or an alternative antifungal may be needed.
DailyMed/FDA (NIH/NLM) — approved Fluconazole label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=7961c029-746c-48c3-888b-8f8344102873 ; approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b — with additional reference: Prontuário Terapêutico do INFARMED, INFARMED (11th ed., 2012)
Rifampin (a CYP450 inducer) markedly reduces Itraconazole levels, risking antifungal treatment failure.
Itraconazole is metabolised by CYP3A4; rifampicin, a potent inducer, can reduce its concentrations and those of the active metabolite (hydroxy-itraconazole) to undetectable levels, with complete loss of antifungal effect. The combination is practically contraindicated; if unavoidable, consider an alternative antifungal (amphotericin B, echinocandins) or monitor itraconazole levels if available.
Itraconazole + rifampicin: rifampicin markedly reduces itraconazole levels (CYP3A4 induction), with antifungal failure. Practically contraindicated.
Enzymatic induction (CYP3A4/P-glycoprotein) by rifampin accelerates itraconazole elimination, reducing efficacy.
Clinical response to the antifungal; liver function tests.
Persistent or worsening fungal infection.
Avoid the combination. If both are needed, use an alternative antifungal and monitor clinical and mycological response.
DailyMed/FDA (NIH/NLM) — approved Itraconazole label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a4d555fa-787c-40fb-bb7d-b0d4f7318fd0 ; approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b — with additional reference: Prontuário Terapêutico do INFARMED, INFARMED (11th ed., 2012)
Rifampin lowers Linezolid levels — risk of losing TB treatment efficacy.
Rifampicin increases linezolid clearance and reduces its exposure by about 30%, even though linezolid is not significantly CYP-metabolised; the clinical relevance is debated, but the failure risk is higher in severe infections (e.g. endocarditis, resistant staphylococcal pneumonia). Monitor the clinical response and consider an alternative (e.g. vancomycin, daptomycin) when the combination is discouraged by the context.
Linezolid + rifampicin: rifampicin lowers linezolid levels (~30%), with possible loss of efficacy. Monitor the clinical response.
Induction of enzymes and transporters that eliminate Linezolid.
Clinical TB response.
Persistent fever, positive sputum smear.
Consider therapeutic drug monitoring or regimen adjustment; watch the response.
DailyMed/FDA (NIH/NLM) — approved Linezolid label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=374af2a7-d994-40bd-a86a-cd9038d0b72c ; approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b
The combination of Praziquantel with Rifampin is contraindicated: Rifampin markedly reduces Praziquantel concentrations, posing a risk of therapeutic failure.
Praziquantel undergoes extensive CYP3A4 first-pass metabolism; rifampicin, a potent inducer, markedly reduces its concentrations and compromises efficacy against schistosomiasis, taeniasis and other parasitoses — a classically label-documented interaction. Avoid the coadministration; if unavoidable, treat the parasitosis after completing the rifampicin regimen or choose an alternative therapy.
Praziquantel + rifampicin: rifampicin markedly reduces praziquantel levels (CYP3A4 induction), with antiparasitic treatment failure. Avoid the combination.
Rifampin, a strong CYP3A4 inducer, increases the hepatic metabolism of Praziquantel, significantly reducing its exposure.
Monitor the parasitological response (e.g. egg clearance) when the combination is unavoidable.
Persisting parasitosis despite treatment suggests failure and requires an alternative strategy.
Do not co-administer; complete Rifampin treatment before starting Praziquantel or choose an alternative antiparasitic treatment.
DailyMed/FDA (NIH/NLM) — approved Praziquantel label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=34ce1cdd-648e-4f1e-8512-bf3d4cc22eb9 ; approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b — with additional reference: Prontuário Terapêutico do INFARMED, INFARMED (11th ed., 2012)
Rifampin lowers Prednisolone levels — reduced anti-inflammatory and immunosuppressive effect.
Prednisolone is metabolised by CYP3A4; rifampicin induces this enzyme and can reduce its concentrations by 30–50%, attenuating the anti-inflammatory/immunosuppressive effect (relevant in autoimmune diseases, transplantation and respiratory diseases). Monitor the clinical response and consider increasing the prednisolone dose during the combination, reducing it after rifampicin discontinuation.
Prednisolone + rifampicin: rifampicin lowers prednisolone levels (CYP3A4 induction), reducing the corticosteroid effect. Consider dose adjustment.
CYP3A4 induction accelerating corticosteroid elimination.
Clinical response; signs of underlying disease flare.
Disease flare (asthma, COPD, autoimmune disease).
Adjust the dose based on response; consider reinforcement during flares.
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Prednisolone label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=52e6e21d-94b8-41a0-8d13-371c0e66bcee
Rifampin markedly lowers Amiodarone levels — risk of arrhythmia recurrence.
Rifampicin is a potent inducer of CYP3A4 and P-glycoprotein and can reduce amiodarone (and active metabolite) concentrations by more than 50%, with loss of antiarrhythmic control. The effect persists for weeks after rifampicin discontinuation given the very long amiodarone half-life (up to 60 days). Avoid the combination when possible; if unavoidable, monitor the rhythm, consider adjusting (often increasing) the amiodarone dose and monitor the ECG.
Rifampicin + amiodarone: rifampicin strongly induces CYP3A4 and can reduce amiodarone levels to subtherapeutic. Avoid or monitor closely.
CYP3A4 induction, the main Amiodarone metabolic pathway.
ECG/rhythm, signs of arrhythmia recurrence.
Palpitations, syncope, tachycardia.
Avoid if possible; if unavoidable, monitor rhythm and consider an alternative.
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Amiodarone label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=51a88e8e-da02-4b97-9e7e-442fbffd908d
Two-way interaction: Rifampin lowers Carbamazepine levels and Carbamazepine lowers Rifampin levels — possible loss of efficacy of both.
Rifampicin is a potent inducer of CYP3A4 and can reduce carbamazepine concentrations by more than 50%, with risk of seizure relapse; the effect develops over days to weeks and persists after rifampicin discontinuation. Both are hepatotoxic, with an additive risk. Monitor carbamazepine plasma levels and increase the dose as needed during and after antituberculosis treatment, monitoring transaminases.
Rifampicin + carbamazepine: rifampicin strongly induces CYP3A4 and lowers carbamazepine levels, with risk of losing seizure control. Monitor levels and adjust the dose.
Mutual enzymatic induction (CYP3A4/2C9).
Carbamazepine levels, seizure control, TB response.
Seizures, persistent TB fever.
Monitor carbamazepine levels and clinical response; adjust doses.
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Carbamazepine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9f3d91cd-a959-4e07-a51b-8a4e9ba9ece2
Rifampin greatly reduces Atorvastatin levels — loss of the lipid-lowering effect.
Rifampicin is a potent inducer of CYP3A4, the main pathway of atorvastatin metabolism; with chronic use it substantially reduces its concentrations and compromises lipid control. Monitor the lipid profile and increase the atorvastatin dose as needed, or prefer a statin less dependent on CYP3A4 (e.g. pravastatin, rosuvastatin) during rifampicin treatment.
Atorvastatin + rifampicin: rifampicin induces CYP3A4 and lowers atorvastatin levels, reducing the lipid-lowering effect. Monitor LDL and adjust the dose.
CYP3A4 induction, the main Atorvastatin metabolic pathway.
Lipid profile.
Rising LDL despite therapy.
Consider another statin or adjust the dose while monitoring lipids.
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Atorvastatin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=86841382-4229-4e03-958e-3ac22639efd4
Rifampin lowers Doxycycline levels — risk of underdosing (e.g. malaria prophylaxis, brucellosis, rickettsial infections).
Rifampicin induces the hepatic enzymes that metabolise doxycycline and can reduce its half-life and concentrations by about 50%, compromising the treatment of brucellosis, rickettsioses and other zoonoses (a classically documented combination). Avoid the association; if unavoidable, consider doubling the doxycycline dose (with monitoring) or choosing an alternative regimen.
Doxycycline + rifampicin: rifampicin accelerates doxycycline metabolism and lowers its levels by ~50%, with risk of therapeutic failure. Avoid or use a doubled dose.
Enzymatic induction accelerating Doxycycline elimination.
Clinical response to infection.
Persistent fever, treatment failure.
Consider an alternative antibiotic or adjust the dose.
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Doxycycline label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cf95b2ca-2cf8-49a8-8e3a-f9b0f5b2072c
Rifampin substantially lowers Bedaquiline levels (about 50%) — risk of failure and resistance in multidrug-resistant TB.
Bedaquiline is metabolised by CYP3A4 and rifampicin, a potent inducer, can reduce its concentrations by more than 50%, compromising multidrug-resistant tuberculosis treatment. The bedaquiline label advises against combination with potent CYP3A4 inducers. The coadministration should be avoided; if needed, consider alternative regimens and monitor the clinical and microbiological response.
Bedaquiline + rifampicin: rifampicin markedly reduces bedaquiline levels (CYP3A4 induction), with risk of therapeutic failure. Avoid the combination.
CYP3A4 induction, the main Bedaquiline metabolic pathway.
Microbiological response (culture and smear).
Persistent positivity, emerging resistance.
Avoid coadministration; if unavoidable, consider therapeutic drug monitoring.
DailyMed/FDA (NIH/NLM) — approved Bedaquiline label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1534c9ae-4948-4cf4-9f66-222a99db6d0e ; approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b
Rifampin lowers Sildenafil levels — loss of efficacy (or need for higher doses).
Sildenafil is metabolised by CYP3A4; rifampicin induces this enzyme and can markedly reduce its concentrations, decreasing the effect in erectile dysfunction or pulmonary hypertension. Monitor the response and consider increasing the sildenafil dose (within approved limits) during the combination, or prefer an alternative less dependent on CYP3A4.
Sildenafil + rifampicin: rifampicin lowers sildenafil levels (CYP3A4 induction), reducing efficacy. Consider dose adjustment.
CYP3A4 induction, the Sildenafil metabolic pathway.
Clinical response.
Lack of effect.
Monitor response; adjust dose (without exceeding the daily maximum).
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Sildenafil label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=00ee09dd-2de0-4dc4-85f6-b51ed6eabd5b
Rifampin (a potent inducer) markedly reduces Voriconazole levels, with a high risk of therapeutic failure.
Voriconazole is metabolised by CYP2C19 and CYP3A4; rifampicin, a potent inducer of both pathways, can reduce its concentrations to nearly undetectable values, with loss of antifungal effect. The combination is practically contraindicated; if unavoidable, consider another antifungal (liposomal amphotericin B, echinocandins) and monitor voriconazole levels if available.
Voriconazole + rifampicin: rifampicin markedly reduces voriconazole levels (CYP3A4/CYP2C19 induction), with antifungal failure. Practically contraindicated.
Potent CYP3A4/CYP2C19 induction by rifampin strongly accelerates voriconazole elimination.
Clinical and mycological response; consider level monitoring.
Antifungal treatment failure (invasive fungal infection).
Avoid the combination (considered contraindicated). Use an alternative antifungal when tuberculosis coexists.
DailyMed/FDA (NIH/NLM) — approved Voriconazole label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f6a1a792-141b-42e8-8bd1-884e4408eb8a ; approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b — with additional reference: Prontuário Terapêutico do INFARMED, INFARMED (11th ed., 2012)
Rifampicin greatly reduces tadalafil blood levels (up to 88% reduction in exposure), which may reduce treatment effectiveness.
Rifampicin is a potent CYP3A4 inducer and reduced tadalafil exposure (AUC) by 88%. Other inducers (phenobarbital, phenytoin, carbamazepine) are expected to act similarly. Tadalafil efficacy may be compromised.
CYP3A4 inducer: rifampicin reduced tadalafil AUC by 88%; efficacy may decrease. Consider an alternative or adjustment.
CYP3A4 induction by rifampicin, accelerating tadalafil clearance.
Clinical response to tadalafil.
Lack of therapeutic effect.
Monitor clinical response; consider an alternative to tadalafil during the rifampicin course.
DailyMed/FDA (NIH/NLM) — approved Tadalafil label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bcd8f8ab-81a2-4891-83db-24a0b0e25895 ; approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Rifampicin reduces vardenafil blood levels, which may reduce treatment effectiveness.
Vardenafil is predominantly metabolised by CYP3A4; rifampicin, a potent inducer of this enzyme, reduces plasma concentrations and may compromise efficacy.
CYP3A4 inducer: rifampicin accelerates vardenafil clearance (CYP3A4 substrate); monitor clinical response.
CYP3A4 induction by rifampicin.
Clinical response to vardenafil.
Lack of therapeutic effect.
Monitor clinical response; consider an alternative during the rifampicin course.
DailyMed/FDA (NIH/NLM) — approved Vardenafil label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=2782efed-6198-47b9-81ac-3e255e2ab7f6 ; approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Rifampicin can markedly reduce the amount of tamoxifen in the body, lowering the effect of treatment. Talk to your doctor if you need to take rifampicin.
The approved tamoxifen label (DailyMed) documents that rifampicin, a CYP3A4 inducer, reduces tamoxifen AUC and Cmax by 86% and 55%, respectively — a loss of exposure that may compromise antitumour efficacy. The EMC-UK SmPC reinforces caution with CYP3A4 inducers. This combination arises mainly in tuberculosis or antibiotic prophylaxis; management should be multidisciplinary.
Potent CYP3A4 inducer (rifampicin) reduces tamoxifen AUC by up to 86%. Avoid the combination whenever possible; if unavoidable, consider an alternative breast cancer treatment and monitor.
CYP3A4 induction by rifampicin, accelerating tamoxifen elimination.
Treatment response and adherence; tamoxifen adverse events.
Clinical worsening; signs of disease progression.
Avoid the combination; if rifampicin is essential (tuberculosis), reassess antineoplastic therapy with the oncologist.
DailyMed/FDA (NIH/NLM) — approved Tamoxifen label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=509f8ba3-214d-aec8-e063-6294a90af498 ; approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Rifampicin can reduce the effect of pioglitazone, requiring blood glucose monitoring and a possible dose increase.
Pioglitazone is mainly metabolised by CYP2C8; rifampicin, a potent inducer of this isoenzyme, reduces pioglitazone AUC by about 54% (EMC-UK SmPC). The reduced exposure can compromise glycaemic control. This combination occurs in patients with tuberculosis and diabetes.
Rifampicin (a CYP2C8 inducer) reduces pioglitazone AUC by 54%; the pioglitazone dose may need to be increased with blood glucose monitoring.
CYP2C8 induction by rifampicin, accelerating pioglitazone metabolism.
Capillary glucose and HbA1c during concurrent treatment.
Hyperglycaemia — thirst, polyuria, fatigue.
Monitor blood glucose and consider increasing the pioglitazone dose during rifampicin; readjust at the end of the antibiotic.
EMC-UK (MHRA) — approved Pioglitazone SmPC: https://www.medicines.org.uk/emc/product/12841/smpc ; DailyMed/FDA (NIH/NLM) — approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Rifampicin can reduce the effectiveness of levonorgestrel. The medicine label itself advises asking a doctor if you take rifampicin (tuberculosis treatment).
The levonorgestrel over-the-counter label (DailyMed) explicitly instructs asking a doctor or pharmacist before use if taking efavirenz or rifampicin (tuberculosis treatment) or seizure medicines, as these can reduce the effectiveness of levonorgestrel. Rifampicin induces CYP3A4 and accelerates progestogen elimination. In patients with tuberculosis, hormonal emergency contraception is unreliable — the copper IUD is the alternative.
The levonorgestrel OTC label warns that rifampicin can reduce effectiveness. In patients taking rifampicin, prefer the copper IUD for emergency contraception and a non-hormonal method for regular contraception.
CYP3A4 induction by rifampicin, accelerating levonorgestrel elimination.
Contraceptive effectiveness.
Unplanned pregnancy.
Prefer the copper IUD for emergency contraception; a non-hormonal method for regular contraception during rifampicin.
DailyMed/FDA (NIH/NLM) — approved Levonorgestrel label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=07567b80-d8a1-41c0-95e4-33afa584bbc4 ; approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Rifampicin can reduce the effect of estradiol, lowering the effectiveness of hormone therapy. Tell your doctor if you are going to take rifampicin.
The approved estradiol label (DailyMed) cites rifampicin among the CYP3A4 inducers that reduce plasma oestrogen concentrations, with possible decreased therapeutic effect and changes in the bleeding pattern. In patients taking rifampicin (e.g. tuberculosis), hormone replacement therapy may be insufficient and hormonal contraceptive effectiveness is compromised.
Rifampicin (a potent CYP3A4 inducer) reduces oestrogen concentrations; monitor the effect and consider a dose adjustment during the antibiotic.
CYP3A4 induction by rifampicin, accelerating oestrogen elimination.
Vasomotor symptoms and bleeding pattern.
Return of symptoms, irregular bleeding.
Watch for return of menopausal symptoms and consider a dose adjustment; use non-hormonal contraception if applicable.
DailyMed/FDA (NIH/NLM) — approved Estradiol label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5718f042-e8c0-b721-e063-6294a90a5bef ; approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Rifampin (a potent CYP3A4 inducer) markedly reduces Artemether and Lumefantrine levels — high risk of malaria treatment failure.
Artemether and lumefantrine are metabolised by CYP3A4; rifampicin is a potent inducer of this isoenzyme and can reduce lumefantrine exposure by more than 90% (AUC), with loss of antimalarial efficacy and risk of relapse or treatment failure. The approved artemether-lumefantrine label contraindicates co-administration with rifampicin. Whenever possible, another antimalarial or an adjusted therapeutic strategy should be chosen; if the combination is unavoidable, monitor clinical response and parasitaemia closely.
Rifampicin (potent CYP3A4 inducer) drastically reduces artemether and lumefantrine levels — risk of malaria treatment failure. Avoid the combination; if unavoidable, consider an alternative antimalarial.
Enzymatic induction accelerating ACT metabolism, with substantial reductions in Lumefantrine exposure.
Clinical and parasitological response; watch for recurrent malaria.
Persistent or recurrent fever, parasitaemia on smear.
Avoid the combination. If rifampin is essential, use an alternative antimalarial regimen and confirm parasitological cure.
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Artemether + Lumefantrine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=7866ec19-dfac-47d4-a53f-511a12643cbf
Rifampin accelerates Warfarin metabolism and lowers the INR — risk of thrombosis from under-anticoagulation.
Rifampicin is one of the most potent inducers of CYP2C9 and CYP3A4, the enzymes that metabolise warfarin. The induction accelerates warfarin elimination and markedly reduces the INR, with thromboembolism risk; studies show reductions of more than 50% in warfarin exposure. Some patients need the warfarin dose doubled or even tripled, with frequent INR monitoring, and the dose must be re-adjusted in the 1–2 weeks after rifampicin is stopped, because the inducing effect fades gradually and the INR can then rise. This interaction is particularly relevant in tuberculosis treatment in anticoagulated patients.
Rifampicin is a potent CYP2C9/CYP3A4 inducer and can markedly REDUCE the effect of warfarin (low INR, thrombosis risk). Warfarin may need to be doubled or tripled with close monitoring.
CYP2C9 (and CYP3A4) induction, the main Warfarin metabolic pathway.
Weekly INR when starting; signs of thrombosis.
DVT/PE, stroke, limb ischaemia.
Monitor the INR when starting/stopping rifampin and adjust the dose.
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Warfarin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=541c9a70-adaf-4ef3-94ba-ad4e70dfa057
Rifampin lowers Digoxin levels (P-glycoprotein induction) — risk of losing control of heart failure or atrial fibrillation.
Rifampicin is a potent P-glycoprotein inducer: it increases transporter expression and accelerates digoxin elimination, reducing its plasma concentrations. The effect can decrease digoxin efficacy (loss of rate control in atrial fibrillation or of heart failure control), sometimes requiring a dose increase. The interaction is particularly relevant in tuberculosis treatment in cardiac patients. Monitor digoxin levels when rifampicin is started and stopped, adjust the digoxin dose as needed and re-evaluate after discontinuation (levels may rise when the inducing effect fades).
Rifampicin induces P-gp and can REDUCE digoxin levels, with loss of efficacy. Monitor digoxin levels and adjust the dose.
Induction of the P-glycoprotein transporter that eliminates Digoxin.
Digoxin levels, heart rate, heart-failure signs.
Worsening dyspnoea, tachyarrhythmias.
Monitor digoxin levels and clinical signs; adjust the dose.
DailyMed/FDA (NIH/NLM) — approved Rifampin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; approved Digoxin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5886e233-b2da-4acb-be05-9bf40fb8e7f4
Food reduces rifampicin absorption; taking it on an empty stomach maximises plasma levels.
Take rifampicin on an empty stomach, 1 hour before or 2 hours after meals.
DailyMed/FDA (NIH/NLM) — approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b
Alcohol adds hepatotoxicity to that of rifampicin and may interfere with tuberculosis treatment adherence.
Avoid alcohol during treatment.
DailyMed/FDA (NIH/NLM) — approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b
Rifampicin induces porphyrin synthesis and may precipitate attacks in patients with porphyria.
Use with caution in patients with porphyria.
DailyMed/FDA (NIH/NLM) — approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b
Rifampicin is hepatotoxic and may worsen pre-existing liver disease.
Monitor transaminases; reduce the dose or stop if liver injury occurs.
DailyMed/FDA (NIH/NLM) — approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b
Rifampicin crosses the placenta; data are limited, but it is used in pregnancy to treat active tuberculosis.
Use in active tuberculosis, with vitamin K supplementation in the neonate and maternal vitamin B6.
Excreted into breast milk; compatible with breastfeeding under supervision.
Rifampicin reduces the efficacy of hormonal contraceptives — use an additional (barrier) method.
DailyMed/FDA (NIH/NLM) — approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Broad-spectrum bactericidal rifamycin. Distributes widely throughout the body, reaching effective concentrations in many organs and body fluids, including cerebrospinal fluid. About 80% is bound to plasma proteins. Potent inducer of multiple enzymes and transporters (CYP1A2, 2B6, 2C8, 2C9, 2C19, 3A4, UGT, P-gp, MRP2) — reduces exposure of numerous drugs.
Inhibits DNA-dependent RNA polymerase activity in susceptible bacteria, namely Mycobacterium tuberculosis; it does not inhibit the mammalian enzyme. Resistance arises by single-step mutations of the RNA polymerase, so it is never used as monotherapy in tuberculosis.
Well absorbed from the gastrointestinal tract: after 600 mg orally the mean peak serum concentration is 7 mcg/mL (range 4–32 mcg/mL), reached 1 to 2 hours after dosing. Food reduces absorption by about 30%.
After absorption it is rapidly eliminated in the bile, with enterohepatic circulation and progressive deacetylation (the deacetylated metabolite retains antibacterial activity). Up to 30% of a dose is excreted in the urine, about half as unchanged drug.
The mean biological half-life is 3.35 ± 0.66 hours after 600 mg orally (5.08 ± 2.45 h after 900 mg); with repeated administration it falls to about 2 to 3 hours. It increases in severe renal failure: up to 11 hours in anuric patients (at 900 mg).
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
