Rifabutin 150mg Capsules
It is used to prevent an infection in people with HIV.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antimycobacterial
Pharmacologic Class
Ansamycin; RNA Polymerase Inhibitor
Pregnancy Category
Category C
FDA Approved
Dec 1992
DEA Schedule
Not Controlled
Overview
What is this medicine?
Rifabutin is an antibiotic used to treat or prevent certain types of bacterial infections, particularly those caused by mycobacteria, such as Mycobacterium avium complex (MAC) in people with HIV, and sometimes as part of a combination treatment for tuberculosis (TB). It works by stopping the growth of these bacteria.
How to Use This Medicine
Taking Your Medication
To take this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. If it causes stomach upset, taking it with food may help. You have the option to swallow the capsule whole or mix its contents with a soft food like applesauce. If you choose to mix it, consume the mixture immediately and do not save it for later use. Continue taking this medication as directed by your doctor or healthcare provider, even if you start feeling well.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a secure place, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about the best disposal method, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Avoid taking two doses at the same time or taking extra doses.
To take this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. If it causes stomach upset, taking it with food may help. You have the option to swallow the capsule whole or mix its contents with a soft food like applesauce. If you choose to mix it, consume the mixture immediately and do not save it for later use. Continue taking this medication as directed by your doctor or healthcare provider, even if you start feeling well.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a secure place, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about the best disposal method, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Avoid taking two doses at the same time or taking extra doses.
Lifestyle & Tips
- Take rifabutin exactly as prescribed by your doctor. Do not skip doses or stop taking it early, even if you feel better, as this can lead to drug resistance.
- You can take rifabutin with or without food. If it causes stomach upset, try taking it with food.
- Rifabutin may cause your urine, feces, saliva, tears, sweat, and contact lenses to turn a reddish-orange color. This is harmless but can permanently stain soft contact lenses.
- If you wear soft contact lenses, you may want to switch to glasses during treatment.
- If you are taking hormonal birth control (pills, patch, ring, injection), rifabutin can make it less effective. Use an additional non-hormonal method of birth control (like condoms) while taking rifabutin and for at least one month after stopping it.
- Avoid alcohol or limit intake as it may increase the risk of liver side effects.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
300 mg orally once daily (for MAC prophylaxis or as part of multi-drug regimen for active TB)
Dose Range:
150 - 450 mg
Condition-Specific Dosing:
MAC Prophylaxis:
300 mg orally once daily
Active Tuberculosis (part of multi-drug regimen):
300 mg orally once daily (adjust based on concomitant medications and tolerability)
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established for MAC prophylaxis; used off-label for TB (dose varies by weight and regimen)
Adolescent:
Not established for MAC prophylaxis; used off-label for TB (dose varies by weight and regimen)
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment recommended
Moderate:
No specific adjustment recommended, monitor for adverse effects
Severe:
Consider dose reduction to 150 mg once daily or 300 mg 3 times weekly; monitor for adverse effects
Dialysis:
No specific recommendations; monitor closely
Hepatic Impairment:
Mild:
No specific adjustment recommended
Moderate:
No specific adjustment recommended, monitor for adverse effects
Severe:
Use with caution; monitor for adverse effects
Pharmacology
Mechanism of Action
Rifabutin is an ansamycin antimycobacterial agent. It inhibits DNA-dependent RNA polymerase in susceptible strains of Mycobacterium tuberculosis and Mycobacterium avium complex (MAC), thereby suppressing RNA synthesis. It is bactericidal.
Pharmacokinetics
Absorption:
Bioavailability:
20% (variable)
Tmax:
2-4 hours
FoodEffect:
Food may slightly decrease Cmax and AUC, but generally not clinically significant; can be taken with food to reduce GI upset.
Distribution:
Vd:
9.3 L/kg (large volume of distribution)
ProteinBinding:
85%
CnssPenetration:
Limited, but detectable in CSF
Elimination:
HalfLife:
45 hours (range 16-69 hours)
Clearance:
Not available
ExcretionRoute:
Fecal (53%), Renal (30%, with approximately 10% as unchanged drug)
Unchanged:
10% (renal)
Pharmacodynamics
OnsetOfAction:
Not precisely defined for clinical effect; antibacterial activity begins rapidly after absorption.
PeakEffect:
Not precisely defined for clinical effect.
DurationOfAction:
Due to long half-life, allows for once-daily dosing.
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash or hives
+ Itching or red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing or tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Chest pain or pressure
Flu-like symptoms, including:
+ Headache
+ Weakness
+ Fever
+ Chills
+ Aches and pains
+ Sweating
Feeling extremely tired or weak
Shortness of breath
Changes in eyesight, eye pain, or severe eye irritation
Dizziness or fainting
Severe stomach upset or vomiting
Coughing
Abnormal heartbeat
Swollen glands
Diarrhea (especially if it's severe, bloody, or watery) - although diarrhea is common with antibiotics, a rare but serious condition called C. diff-associated diarrhea (CDAD) can occur, which may lead to life-threatening bowel problems
Severe skin reactions, including:
+ Stevens-Johnson syndrome (SJS)
+ Toxic epidermal necrolysis (TEN)
+ Other serious reactions that can affect body organs and be life-threatening
+ Signs of severe skin reactions include:
- Red, swollen, blistered, or peeling skin
- Red or irritated eyes
- Sores in the mouth, throat, nose, eyes, genitals, or skin
- Fever
- Chills
- Body aches
- Shortness of breath
- Swollen glands
Low white blood cell counts, which can increase the risk of infection - seek medical help if you experience:
+ Fever
+ Chills
+ Sore throat
Low platelet counts, which can increase the risk of bleeding - seek medical help if you notice:
+ Unexplained bruising
+ Unexplained bleeding
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or don't go away, contact your doctor:
Diarrhea
* Upset stomach
Reporting Side Effects
If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash or hives
+ Itching or red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing or tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Chest pain or pressure
Flu-like symptoms, including:
+ Headache
+ Weakness
+ Fever
+ Chills
+ Aches and pains
+ Sweating
Feeling extremely tired or weak
Shortness of breath
Changes in eyesight, eye pain, or severe eye irritation
Dizziness or fainting
Severe stomach upset or vomiting
Coughing
Abnormal heartbeat
Swollen glands
Diarrhea (especially if it's severe, bloody, or watery) - although diarrhea is common with antibiotics, a rare but serious condition called C. diff-associated diarrhea (CDAD) can occur, which may lead to life-threatening bowel problems
Severe skin reactions, including:
+ Stevens-Johnson syndrome (SJS)
+ Toxic epidermal necrolysis (TEN)
+ Other serious reactions that can affect body organs and be life-threatening
+ Signs of severe skin reactions include:
- Red, swollen, blistered, or peeling skin
- Red or irritated eyes
- Sores in the mouth, throat, nose, eyes, genitals, or skin
- Fever
- Chills
- Body aches
- Shortness of breath
- Swollen glands
Low white blood cell counts, which can increase the risk of infection - seek medical help if you experience:
+ Fever
+ Chills
+ Sore throat
Low platelet counts, which can increase the risk of bleeding - seek medical help if you notice:
+ Unexplained bruising
+ Unexplained bleeding
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or don't go away, contact your doctor:
Diarrhea
* Upset stomach
Reporting Side Effects
If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Eye pain, redness, or blurred vision (report immediately, as this could be a serious eye condition called uveitis)
- Severe skin rash, blistering, or peeling
- Fever, chills, sore throat, unusual tiredness, or easy bruising/bleeding (signs of blood problems)
- Yellowing of the skin or eyes (jaundice), dark urine, severe stomach pain (signs of liver problems)
- Severe diarrhea, especially if it contains blood or mucus
- Joint pain or swelling
Before Using This Medicine
Before taking this medication, it is essential to inform your doctor about the following:
Any allergies you have, including allergies to this drug, any of its components, or other substances, such as foods or medications. Be sure to describe the symptoms you experienced as a result of the allergy.
If you have been diagnosed with tuberculosis (TB).
If you are currently taking voriconazole.
If you are taking any medications to treat HIV, as some HIV treatments are not compatible with this drug.
It is crucial to note that this is not an exhaustive list of all potential interactions between this medication and other substances. Therefore, it is vital to disclose all of your medications, including prescription and over-the-counter drugs, natural products, and vitamins, as well as any health problems you may have, to your doctor and pharmacist. This will enable them to verify that it is safe for you to take this medication in conjunction with your other treatments. Never initiate, discontinue, or adjust the dosage of any medication without first consulting your doctor.
Any allergies you have, including allergies to this drug, any of its components, or other substances, such as foods or medications. Be sure to describe the symptoms you experienced as a result of the allergy.
If you have been diagnosed with tuberculosis (TB).
If you are currently taking voriconazole.
If you are taking any medications to treat HIV, as some HIV treatments are not compatible with this drug.
It is crucial to note that this is not an exhaustive list of all potential interactions between this medication and other substances. Therefore, it is vital to disclose all of your medications, including prescription and over-the-counter drugs, natural products, and vitamins, as well as any health problems you may have, to your doctor and pharmacist. This will enable them to verify that it is safe for you to take this medication in conjunction with your other treatments. Never initiate, discontinue, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Regular blood tests will be necessary, as directed by your doctor, to monitor your condition. Be sure to discuss any concerns or questions with your doctor.
Please note that this medication may cause discoloration of contact lenses. Additionally, it can change the color of your urine, stools, saliva, sweat, tears, and skin to a brown-orange hue. This is a normal and harmless side effect.
If you are using birth control pills or other hormone-based birth control methods, you should be aware that this medication may reduce their effectiveness in preventing pregnancy. To minimize the risk of unplanned pregnancy, consider using an additional form of birth control, such as a condom, while taking this drug.
If you are pregnant, planning to become pregnant, or breastfeeding, it is crucial to consult with your doctor. You will need to discuss the potential benefits and risks of this medication to both you and your baby to make an informed decision.
Please note that this medication may cause discoloration of contact lenses. Additionally, it can change the color of your urine, stools, saliva, sweat, tears, and skin to a brown-orange hue. This is a normal and harmless side effect.
If you are using birth control pills or other hormone-based birth control methods, you should be aware that this medication may reduce their effectiveness in preventing pregnancy. To minimize the risk of unplanned pregnancy, consider using an additional form of birth control, such as a condom, while taking this drug.
If you are pregnant, planning to become pregnant, or breastfeeding, it is crucial to consult with your doctor. You will need to discuss the potential benefits and risks of this medication to both you and your baby to make an informed decision.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Abdominal pain
- Headache
- Dizziness
- Leukopenia (low white blood cell count)
- Thrombocytopenia (low platelet count)
- Elevated liver enzymes
What to Do:
In case of suspected overdose, seek immediate medical attention or call a poison control center (e.g., 1-800-222-1222 in the US). Treatment is supportive and symptomatic; there is no specific antidote. Gastric lavage may be considered.
Drug Interactions
Contraindicated Interactions
- Voriconazole (significant decrease in voriconazole levels, loss of efficacy)
Major Interactions
- Protease Inhibitors (e.g., Ritonavir, Saquinavir, Indinavir, Nelfinavir - significant dose adjustments required for both agents, increased risk of adverse effects like uveitis with some combinations)
- Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs) (e.g., Efavirenz, Nevirapine - potential for decreased NNRTI levels)
- Oral Contraceptives (decreased efficacy of hormonal contraceptives, use alternative birth control)
- Clarithromycin (increased rifabutin levels, significantly increased risk of uveitis; consider rifabutin dose reduction)
- Warfarin (decreased anticoagulant effect)
- Cyclosporine, Tacrolimus, Sirolimus (decreased immunosuppressant levels)
- Corticosteroids (decreased corticosteroid levels)
- Dapsone (decreased dapsone levels)
- Methadone (decreased methadone levels, risk of withdrawal)
- Quinidine (decreased quinidine levels)
- Sildenafil, Tadalafil, Vardenafil (decreased PDE5 inhibitor levels)
- Theophylline (decreased theophylline levels)
- Digoxin (potential for decreased digoxin levels)
- Phenytoin, Carbamazepine, Phenobarbital (potential for altered anticonvulsant levels)
Moderate Interactions
- Azithromycin (potential for increased rifabutin levels, monitor for uveitis)
- Fluconazole, Itraconazole, Ketoconazole (potential for increased rifabutin levels, monitor for adverse effects)
- Sulfonylureas (potential for decreased hypoglycemic effect)
- Beta-blockers (potential for decreased beta-blocker levels)
- Calcium Channel Blockers (potential for decreased calcium channel blocker levels)
- Statins (potential for decreased statin levels)
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Complete Blood Count (CBC) with differential
Rationale: To establish baseline neutrophil count, as neutropenia is a potential adverse effect.
Timing: Prior to initiation of therapy
Liver Function Tests (LFTs) - AST, ALT, Bilirubin
Rationale: To establish baseline liver function, as hepatic impairment can occur.
Timing: Prior to initiation of therapy
Renal Function (BUN, Creatinine)
Rationale: To assess baseline renal function, especially if dose adjustment may be considered for severe impairment.
Timing: Prior to initiation of therapy
Routine Monitoring
Complete Blood Count (CBC) with differential
Frequency: Monthly or as clinically indicated, especially during the first few months of therapy
Target: Maintain neutrophil count >1000 cells/mm³
Action Threshold: If neutrophil count falls below 1000 cells/mm³, consider dose reduction or interruption; if severe neutropenia, discontinue.
Liver Function Tests (LFTs)
Frequency: Periodically or as clinically indicated
Target: Within normal limits or stable
Action Threshold: Significant elevations may warrant dose adjustment or discontinuation.
Ophthalmic Examination
Frequency: If symptoms of uveitis develop (e.g., eye pain, redness, blurred vision)
Target: Not applicable
Action Threshold: Prompt evaluation and potential discontinuation if uveitis is confirmed.
Symptom Monitoring
- Eye pain, redness, blurred vision (signs of uveitis)
- Skin rash, itching, hives
- Fever, sore throat, unusual tiredness (signs of neutropenia or other infection)
- Unusual bleeding or bruising
- Joint pain or swelling
- Nausea, vomiting, abdominal pain
- Yellowing of skin or eyes (jaundice), dark urine (signs of liver problems)
Special Patient Groups
Pregnancy
Rifabutin is Pregnancy Category C. Animal studies have shown adverse effects on the fetus, but there are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Potential for teratogenicity based on animal data; human data limited.
Second Trimester:
Limited human data; use only if clearly needed.
Third Trimester:
Limited human data; use only if clearly needed.
Lactation
Rifabutin is excreted into human breast milk. Due to the potential for serious adverse reactions in nursing infants (e.g., discoloration of body fluids, theoretical risk of developing drug-resistant organisms), a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Infant Risk:
L3 (Moderately Safe) - Limited human data, potential for adverse effects (e.g., reddish-orange discoloration of body fluids, theoretical risk of resistance development). Monitor infant for GI upset, rash, and discoloration.
Pediatric Use
Safety and efficacy have not been established in pediatric patients under 18 years of age for MAC prophylaxis. It is used off-label for the treatment of tuberculosis in children as part of multi-drug regimens, with doses adjusted by weight. Close monitoring for adverse effects is crucial.
Geriatric Use
No specific dose adjustment is generally required for elderly patients. However, due to the higher likelihood of decreased renal or hepatic function and polypharmacy in this population, close monitoring for adverse effects and drug interactions is recommended.
Clinical Information
Clinical Pearls
- Rifabutin is a potent inducer of CYP3A4, leading to numerous significant drug interactions, especially with antiretrovirals (PIs, NNRTIs), oral contraceptives, and immunosuppressants. Careful medication reconciliation and dose adjustments are often necessary.
- The most notable adverse effect is uveitis, particularly at higher doses or when co-administered with clarithromycin. Patients should be educated to report any eye pain, redness, or blurred vision immediately.
- Causes reddish-orange discoloration of urine, feces, saliva, tears, sweat, and contact lenses. This is a benign effect but can be alarming to patients.
- Neutropenia is a potential hematologic side effect; regular CBC monitoring is important, especially during the initial months of therapy.
- Often used as an alternative to rifampin in TB regimens when drug interactions with rifampin are problematic (e.g., with certain HIV medications), though rifabutin still has significant interactions.
Alternative Therapies
- For MAC: Azithromycin, Clarithromycin, Ethambutol, Amikacin, Streptomycin
- For TB: Isoniazid, Pyrazinamide, Ethambutol, Moxifloxacin, Levofloxacin, Bedaquiline, Pretomanid, Delamanid
Cost & Coverage
Average Cost:
Varies widely, typically $100-$500+ per 30 capsules (150mg)
Generic Available:
Yes
Insurance Coverage:
Tier 2 or 3 (often requires prior authorization for non-HIV related uses)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.