Rifabac
Generic Name
Rifabutin
Manufacturer
Reputable Pharmaceutical Company
Country
Bangladesh
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Price Details
Current market pricing information
| Variant | Unit Price | Strip Price |
|---|---|---|
| rifabac 200 mg tablet | ৳ 25.00 | ৳ 250.00 |
Description
Overview of the medicine
Rifabutin is an antimycobacterial drug primarily used in the treatment and prophylaxis of Mycobacterium avium complex (MAC) disease, especially in patients with advanced HIV infection. It is also used in certain multidrug regimens for tuberculosis.
Uses & Indications
Dosage
Adults
For MAC prophylaxis: 300 mg once daily. For MAC treatment: 300-450 mg once daily in combination with other agents. For TB: 300-450 mg once daily as part of a multidrug regimen.
Elderly
No specific dosage adjustment is generally required, but caution is advised due to potential age-related decrease in renal and hepatic function.
Renal_impairment
For creatinine clearance <30 mL/min, reduce dosage by 50% (e.g., 150 mg once daily for MAC prophylaxis).
How to Take
Take orally, with or without food. Taking with food may improve gastrointestinal tolerability. Swallow the tablet whole with water.
Mechanism of Action
Rifabutin inhibits DNA-dependent RNA polymerase in susceptible Mycobacterium species, thereby blocking bacterial RNA synthesis and leading to cell death. It has a broader spectrum of activity against mycobacteria than rifampicin.
Pharmacokinetics
Onset
Not acutely observable; therapeutic effects develop over days to weeks.
Excretion
Approximately 53% excreted in urine (10% as unchanged drug, 43% as metabolites) and 30% in feces.
Half life
Approximately 45 hours (range 25-66 hours), allowing for once-daily dosing.
Absorption
Well absorbed from the gastrointestinal tract; absolute bioavailability is about 20%. Peak plasma concentrations occur 2-4 hours after administration.
Metabolism
Extensively metabolized in the liver, primarily by CYP3A4, to several metabolites, including the active 25-O-desacetyl rifabutin (metabolite 1), which contributes significantly to antibacterial activity.
Side Effects
Contraindications
- Hypersensitivity to rifabutin, other rifamycins, or any component of the formulation.
- Concomitant use with voriconazole (due to increased rifabutin levels and potential for serious adverse effects).
Drug Interactions
Warfarin
May decrease warfarin effect; monitor INR closely.
Clarithromycin
Increases rifabutin levels, increasing risk of uveitis and neutropenia; concomitant use not recommended or requires significant dose reduction of rifabutin.
Oral Contraceptives
May reduce efficacy of oral contraceptives; advise alternative contraception.
NNRTIs (e.g., Efavirenz)
May decrease rifabutin levels, potentially requiring rifabutin dose increase.
Protease Inhibitors (e.g., Ritonavir, Saquinavir)
Significant interactions; requires dose adjustment of rifabutin and/or protease inhibitor. May increase rifabutin levels and reduce PI levels.
Storage
Store below 30°C in a dry place, away from light and moisture. Keep out of reach of children.
Overdose
Limited information on acute overdose. Symptoms may include nausea, vomiting, abdominal pain, leukopenia. Management is symptomatic and supportive. Gastric lavage may be considered.
Pregnancy & Lactation
Pregnancy Category C. Use only if the potential benefit justifies the potential risk to the fetus. It is unknown if rifabutin is excreted in human milk; use with caution in breastfeeding mothers.
Side Effects
Contraindications
- Hypersensitivity to rifabutin, other rifamycins, or any component of the formulation.
- Concomitant use with voriconazole (due to increased rifabutin levels and potential for serious adverse effects).
Drug Interactions
Warfarin
May decrease warfarin effect; monitor INR closely.
Clarithromycin
Increases rifabutin levels, increasing risk of uveitis and neutropenia; concomitant use not recommended or requires significant dose reduction of rifabutin.
Oral Contraceptives
May reduce efficacy of oral contraceptives; advise alternative contraception.
NNRTIs (e.g., Efavirenz)
May decrease rifabutin levels, potentially requiring rifabutin dose increase.
Protease Inhibitors (e.g., Ritonavir, Saquinavir)
Significant interactions; requires dose adjustment of rifabutin and/or protease inhibitor. May increase rifabutin levels and reduce PI levels.
Storage
Store below 30°C in a dry place, away from light and moisture. Keep out of reach of children.
Overdose
Limited information on acute overdose. Symptoms may include nausea, vomiting, abdominal pain, leukopenia. Management is symptomatic and supportive. Gastric lavage may be considered.
Pregnancy & Lactation
Pregnancy Category C. Use only if the potential benefit justifies the potential risk to the fetus. It is unknown if rifabutin is excreted in human milk; use with caution in breastfeeding mothers.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
2-3 years from manufacturing date
Availability
Available in pharmacies and hospitals
Approval Status
Approved
Patent Status
Patent expired for generic formulation
WHO Essential Medicine
YesClinical Trials
Rifabutin has undergone extensive clinical trials demonstrating efficacy in MAC prophylaxis and treatment, and in specific TB regimens, particularly in HIV-infected populations. Ongoing research continues to explore its role in drug-resistant TB.
Lab Monitoring
- Complete Blood Count (CBC) with differential, including neutrophil count, periodically.
- Liver function tests (ALT, AST, bilirubin) periodically.
- Renal function tests (creatinine, BUN) if renal impairment is a concern.
Doctor Notes
- Crucial to monitor for drug interactions, especially with antiretroviral therapies and other CYP3A4 inhibitors/inducers.
- Advise patients to report any visual changes promptly to rule out uveitis, which can lead to permanent vision loss if untreated.
- Consider rifabutin as an alternative to rifampicin in HIV/TB co-infection where potent CYP450 induction by rifampicin is problematic.
Patient Guidelines
- Take the medicine exactly as prescribed by your doctor; do not stop without consulting your doctor.
- Report any signs of eye pain, redness, or blurred vision immediately to your doctor as these could be symptoms of uveitis.
- Be aware that rifabutin may cause your urine, sweat, saliva, and tears to turn orange-red; this is harmless but can permanently stain soft contact lenses.
Missed Dose Advice
If a dose is missed, take it as soon as remembered. If it is almost time for the next dose, skip the missed dose and resume your regular dosing schedule. Do not double the dose to catch up.
Driving Precautions
Rifabutin may cause dizziness or visual disturbances (e.g., blurred vision due to uveitis) in some patients. Patients should be advised to exercise caution when driving or operating machinery until they know how the drug affects them.
Lifestyle Advice
- Avoid alcohol consumption, especially if you have pre-existing liver conditions, as rifabutin can affect liver function.
- Maintain good hydration.
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