Mycobutin 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 antibiotic
Pregnancy Category
Category C
FDA Approved
Dec 1992
DEA Schedule
Not Controlled
Overview
What is this medicine?
Rifabutin is an antibiotic used to treat and prevent certain types of serious bacterial infections, particularly those caused by mycobacteria, such as Mycobacterium avium complex (MAC) in people with HIV. It works by stopping the growth of these bacteria.
How to Use This Medicine
Taking Your Medication
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. 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, be sure to take the mixture right away and do not save it for later use.
It's essential to continue taking this medication as directed by your doctor or healthcare provider, even if you start feeling well. This will help ensure that you receive the full benefits of the treatment.
Storing and Disposing of Your Medication
To keep your medication effective and safe, store it at room temperature in a dry place, avoiding the bathroom. Keep all medications out of the reach of children and pets to prevent accidents. When your medication is no longer needed or has expired, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. If you're unsure about the best way to dispose of your medication, consult your pharmacist. They may be aware of drug take-back programs in your area that can help.
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 continue with your regular dosing schedule. It's crucial not to take two doses at the same time or to take extra doses, as this can increase the risk of side effects.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. 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, be sure to take the mixture right away and do not save it for later use.
It's essential to continue taking this medication as directed by your doctor or healthcare provider, even if you start feeling well. This will help ensure that you receive the full benefits of the treatment.
Storing and Disposing of Your Medication
To keep your medication effective and safe, store it at room temperature in a dry place, avoiding the bathroom. Keep all medications out of the reach of children and pets to prevent accidents. When your medication is no longer needed or has expired, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. If you're unsure about the best way to dispose of your medication, consult your pharmacist. They may be aware of drug take-back programs in your area that can help.
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 continue with your regular dosing schedule. It's crucial not to take two doses at the same time or to take extra doses, as this can increase the risk of side effects.
Lifestyle & Tips
- Take rifabutin exactly as prescribed by your doctor, usually once a day. Do not skip doses or stop taking it without consulting your doctor.
- You can take rifabutin with or without food. If it causes stomach upset, try taking it with food.
- Rifabutin can cause your urine, feces, saliva, sweat, and tears to turn an orange-red color. This is a harmless side effect, but it can permanently stain soft contact lenses. Consider wearing eyeglasses instead of contact lenses while taking this medication.
- If you are taking birth control pills, rifabutin can make them less effective. Discuss alternative or additional birth control methods with your doctor.
- Avoid alcohol or limit its consumption as it may increase the risk of liver side effects.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
300 mg once daily (for MAC prophylaxis/treatment, as part of multi-drug regimen)
Dose Range:
150 - 600 mg
Condition-Specific Dosing:
MAC Prophylaxis:
300 mg once daily
MAC Treatment:
300-450 mg once daily (as part of multi-drug regimen)
Tuberculosis (off-label, when rifampin not tolerated/resistant):
300-600 mg once daily (as part of multi-drug regimen)
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
MAC Prophylaxis: 5 mg/kg/day (max 300 mg/day); MAC Treatment: 10-15 mg/kg/day (max 600 mg/day)
Adolescent:
MAC Prophylaxis: 5 mg/kg/day (max 300 mg/day); MAC Treatment: 10-15 mg/kg/day (max 600 mg/day)
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment recommended
Moderate:
No specific adjustment recommended
Severe:
Reduce dose by 50% for CrCl < 30 mL/min
Dialysis:
No specific recommendations; monitor closely
Hepatic Impairment:
Mild:
No specific adjustment recommended
Moderate:
No specific adjustment recommended; use with caution
Severe:
No specific adjustment recommended; use with caution and monitor closely
Pharmacology
Mechanism of Action
Rifabutin is an ansamycin antibiotic that inhibits DNA-dependent RNA polymerase in susceptible strains of Mycobacterium, leading to suppression of RNA synthesis. It is active against Mycobacterium avium complex (MAC) and Mycobacterium tuberculosis.
Pharmacokinetics
Absorption:
Bioavailability:
20% (variable)
Tmax:
2-4 hours
FoodEffect:
Food may slightly decrease Cmax and AUC, but not clinically significant; can be taken with food to reduce GI upset.
Distribution:
Vd:
9.3 L/kg
ProteinBinding:
85%
CnssPenetration:
Limited, but achieves therapeutic concentrations in CSF in meningitis.
Elimination:
HalfLife:
45 hours (range 16-69 hours)
Clearance:
Not available
ExcretionRoute:
Approximately 53% urine, 30% feces
Unchanged:
Approximately 10% (in urine)
Pharmacodynamics
OnsetOfAction:
Not immediately applicable for chronic infection treatment; therapeutic effects seen over days to weeks.
PeakEffect:
Not immediately applicable for chronic infection treatment.
DurationOfAction:
Due to long half-life, allows for once-daily dosing.
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ 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
+ 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 is severe, bloody, or accompanied by stomach pain or cramps (note: diarrhea is common with antibiotics, but rare cases of C. diff-associated diarrhea (CDAD) can occur, potentially leading to life-threatening bowel problems)
Severe skin reactions, including:
+ Stevens-Johnson syndrome (SJS)
+ Toxic epidermal necrolysis (TEN)
+ Other serious reactions, which may affect body organs and can 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 (contact your doctor if you experience signs of infection, such as fever, chills, or sore throat)
Low platelet counts, which can increase the risk of bleeding (contact your doctor if you experience unexplained bruising or bleeding)
Other Possible Side Effects
Most people do not experience significant side effects, but some may occur. If you experience any of the following side effects or any other unusual symptoms, contact your doctor or seek medical attention:
Diarrhea
Stomach upset
Other side effects not listed here
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 experience any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ 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
+ 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 is severe, bloody, or accompanied by stomach pain or cramps (note: diarrhea is common with antibiotics, but rare cases of C. diff-associated diarrhea (CDAD) can occur, potentially leading to life-threatening bowel problems)
Severe skin reactions, including:
+ Stevens-Johnson syndrome (SJS)
+ Toxic epidermal necrolysis (TEN)
+ Other serious reactions, which may affect body organs and can 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 (contact your doctor if you experience signs of infection, such as fever, chills, or sore throat)
Low platelet counts, which can increase the risk of bleeding (contact your doctor if you experience unexplained bruising or bleeding)
Other Possible Side Effects
Most people do not experience significant side effects, but some may occur. If you experience any of the following side effects or any other unusual symptoms, contact your doctor or seek medical attention:
Diarrhea
Stomach upset
Other side effects not listed here
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 (signs of uveitis – seek immediate medical attention)
- Fever, chills, sore throat, unusual tiredness, or easy bruising/bleeding (signs of low white blood cell count or other blood problems)
- Severe stomach pain, nausea, vomiting, or diarrhea
- Yellowing of the skin or eyes (jaundice), dark urine, or pale stools (signs of liver problems)
- New or worsening rash
- Joint pain or swelling
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have been diagnosed with tuberculosis (TB).
If you are currently taking voriconazole.
If you are taking any medications to treat HIV. Certain HIV treatments are not compatible with this medication and should not be taken together.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your existing treatments and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor to ensure your safety.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have been diagnosed with tuberculosis (TB).
If you are currently taking voriconazole.
If you are taking any medications to treat HIV. Certain HIV treatments are not compatible with this medication and should not be taken together.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your existing treatments and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor to ensure your safety.
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, please be aware that this medication may reduce their effectiveness in preventing pregnancy. To ensure adequate contraception, consider using an additional method, 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, please be aware that this medication may reduce their effectiveness in preventing pregnancy. To ensure adequate contraception, consider using an additional method, 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
- Headache
- Dizziness
- Leukopenia (low white blood cell count)
- Thrombocytopenia (low platelet count)
- Elevated liver enzymes
- Uveitis (eye inflammation)
What to Do:
In case of suspected overdose, seek immediate medical attention or call a poison control center (e.g., 1-800-222-1222). Treatment is supportive and symptomatic. Gastric lavage may be considered.
Drug Interactions
Contraindicated Interactions
- Voriconazole (significant decrease in voriconazole levels)
Major Interactions
- Protease Inhibitors (e.g., Indinavir, Nelfinavir, Ritonavir, Saquinavir, Atazanavir, Darunavir, Lopinavir): Significant decrease in PI levels, potential increase in rifabutin levels. Dose adjustments required.
- NNRTIs (e.g., Efavirenz, Nevirapine, Etravirine, Rilpivirine): Decrease in NNRTI levels. Dose adjustments required.
- Oral Contraceptives: Decreased efficacy of hormonal contraceptives, leading to potential pregnancy.
- Warfarin: Decreased anticoagulant effect.
- Cyclosporine, Tacrolimus, Sirolimus: Decreased immunosuppressant levels.
- Corticosteroids: Decreased corticosteroid levels.
- Dapsone: Decreased dapsone levels.
- Clarithromycin: Increased rifabutin levels, significantly increased risk of uveitis. Dose adjustment of rifabutin required.
- Azole Antifungals (e.g., Fluconazole, Itraconazole, Posaconazole): Increased rifabutin levels. Dose adjustment of rifabutin required.
- Methadone: Decreased methadone levels, leading to potential withdrawal symptoms.
- Digoxin: Decreased digoxin levels.
- Theophylline: Decreased theophylline levels.
Moderate Interactions
- Calcium Channel Blockers (e.g., Amlodipine, Diltiazem, Verapamil): Decreased calcium channel blocker levels.
- Beta-blockers (e.g., Metoprolol, Propranolol): Decreased beta-blocker levels.
- Antidepressants (e.g., Tricyclic antidepressants, SSRIs): Potential for decreased antidepressant levels.
- Antiepileptics (e.g., Phenytoin, Carbamazepine): Potential for decreased antiepileptic levels.
- Sulfonylureas: Potential for decreased hypoglycemic effect.
Minor Interactions
- Not available (most interactions are significant due to CYP3A4 induction)
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)
Rationale: To establish baseline liver function, as hepatic impairment can occur.
Timing: Prior to initiation of therapy
Routine Monitoring
Complete Blood Count (CBC) with differential
Frequency: Monthly for the first 2-3 months, then periodically as clinically indicated
Target: Maintain neutrophil count > 1000 cells/mm³
Action Threshold: If neutrophil count falls below 1000 cells/mm³ or significant decrease, consider dose reduction or discontinuation.
Liver Function Tests (LFTs)
Frequency: Periodically, or if symptoms of hepatic dysfunction develop
Target: Within normal limits or stable
Action Threshold: Significant elevation (e.g., >3x ULN) or worsening of LFTs may require dose adjustment or discontinuation.
Ophthalmic examination
Frequency: If visual changes occur, or if patient is on high doses or concomitant clarithromycin
Target: Normal vision, absence of uveitis symptoms
Action Threshold: Any visual changes, eye pain, or redness should prompt immediate ophthalmologic evaluation.
Symptom Monitoring
- Fever
- Rash
- Joint pain
- Muscle pain
- Abdominal pain
- Nausea/Vomiting
- Unusual bleeding or bruising
- Sore throat
- Fatigue
- Yellowing of skin or eyes (jaundice)
- Dark urine
- Eye pain
- Redness of eyes
- Blurred vision
- Changes in vision
Special Patient Groups
Pregnancy
Category C. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Limited human data suggest no increased risk of major birth defects, but animal studies show some adverse effects.
Trimester-Specific Risks:
First Trimester:
Limited human data, animal studies show some teratogenicity at high doses.
Second Trimester:
Limited human data, generally considered if benefit outweighs risk.
Third Trimester:
Limited human data, generally considered if benefit outweighs risk.
Lactation
Rifabutin is excreted into breast milk. Due to the potential for serious adverse reactions in the nursing infant (e.g., orange discoloration, potential for bacterial resistance), 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. L3 (Moderately Safe) or L4 (Possibly Hazardous) depending on source and interpretation of limited data.
Infant Risk:
Potential for orange discoloration of body fluids, theoretical risk of bacterial resistance, and other adverse effects observed in adults (e.g., neutropenia, uveitis).
Pediatric Use
Dosing is established for children for MAC prophylaxis and treatment. Safety and efficacy in children younger than 6 months have not been established. Monitor for adverse effects similar to adults.
Geriatric Use
No specific dose adjustment is recommended based on age alone. However, elderly patients may have reduced renal or hepatic function, which could necessitate dose adjustments based on individual organ function. Monitor closely for adverse effects.
Clinical Information
Clinical Pearls
- Rifabutin is a potent inducer of CYP3A4, leading to numerous significant drug interactions, especially with antiretrovirals (PIs, NNRTIs) and hormonal contraceptives.
- Orange-red discoloration of urine, feces, sweat, tears, and contact lenses is a common and harmless side effect. Patients should be counseled about this.
- Uveitis (eye inflammation) is a dose-related adverse effect, and its risk is significantly increased when rifabutin is co-administered with clarithromycin. Dose reduction of rifabutin is often required in such combinations.
- Neutropenia (low white blood cell count) is another important adverse effect, requiring regular monitoring of CBC.
- Used primarily for the prevention and treatment of Mycobacterium avium complex (MAC) disease, particularly in HIV-infected patients. Also used off-label for tuberculosis when rifampin is not tolerated or resistance is present.
Alternative Therapies
- For MAC: Clarithromycin, Azithromycin, Ethambutol, Amikacin, Streptomycin (typically used in combination regimens).
- For Tuberculosis: Rifampin, Isoniazid, Pyrazinamide, Ethambutol (first-line agents).
Cost & Coverage
Average Cost:
Check current market prices (generic available) per 30 capsules
Generic Available:
Yes
Insurance Coverage:
Tier 2 or 3 (for generic), Tier 3 or 4 (for brand)
General Drug Facts
If your symptoms or health issues persist or worsen, it's 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 seeking help, be prepared to provide information about what was taken, the amount, and the time it happened.