rifabutin

Appears to inhibit DNA-dependent RNA polymerase in susceptible organisms.

Therapeutic effects:

Antimycobacterial action against susceptible organisms.

Spectrum:

Active against M. avium and most strains of M. tuberculosis.

Pharmacokinetics ⬆ ⬇

Absorption: Well absorbed following oral administration (50–85%). Absorption ↓ in patients with HIV (20%).

Distribution: Widely distributed to body tissues and fluids.

Metabolism/Excretion: Mostly metabolized by the liver; <5% excreted unchanged by the kidneys.

Half-Life: 45 hr.

Time/Action Profile ⬆ ⬇

(plasma concentrations)

ROUTE	ONSET	PEAK	DURATION
PO	rapid	2–4 hr	24 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity. Cross-sensitivity with other rifamycins (rifampin) may occur;
Active tuberculosis;
Concurrent use of ritonavir;
Lactation: Lactation.

Use Cautiously in:

OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: chest pain, chest pressure

Derm: ACUTE GENERALIZED EXANTHEMATOUS PUSTULOSIS, DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), rash, skin discoloration, STEVENS-JOHNSON SYNDROME (SJS), TOXIC EPIDERMAL NECROLYSIS (TEN)

EENT: ocular disturbances

GI: altered taste, CLOSTRIDIOIDES DIFFICILE-ASSOCIATED DIARRHEA (CDAD), drug-induced hepatitis

Hemat: hemolysis, neutropenia, thrombocytopenia

MS: arthralgia, myositis

Resp: dyspnea

Misc: brown-orange discoloration of body fluids (urine, tears, saliva), flu-like syndrome

Interactions ⬆ ⬇

Drug-drug:

Ritonavir may significantly ↑ levels; concurrent use contraindicated.
May ↓ levels and effectiveness of efavirenz, nelfinavir, nevirapine, corticosteroids, disopyramide, quinidine, opioid analgesics, oral hypoglycemic agents, warfarin, estrogens, estrogen-containing contraceptives, phenytoin, verapamil, fluconazole, quinidine, theophylline, zidovudine, and chloramphenicol.
May ↓ levels and effectiveness of bictegravir and tenofovir alafenamide; concurrent use with bictegravir/emtricitabine/tenofovir alafenamide is not recommended.
May ↓ levels and effectiveness of doravirine; ↑ doravirine dose.
May ↓ levels and effectiveness of rilpivirine and tenofovir alafenamide; concurrent use with rilpivirine/tenofovir alafenamide/emtricitabine is not recommended.
Efavirenz and nevirapine may ↑ levels.

Route/Dosage ⬆ ⬇

PO (Adults ): 300 mg once daily. If GI upset occurs, may give as 150 mg twice daily with food.

Availability ⬆ ⬇

(Generic available)

Capsules: 150 mg
In combination with: amoxicillin and omeprazole (Talicia). See Appendix [not included in this PDA edition].

Assessment ⬆ ⬇

Monitor patient for signs of active tuberculosis (purified protein derivative [PPD], chest x-ray, sputum culture, blood culture, urine culture, biopsy of suspicious lymph nodes) prior to and during therapy. Rifabutin must not be administered to patients with active tuberculosis.
Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care professional promptly as a sign of CDAD. May begin up to several wk following cessation of therapy.
Assess patient for skin rash frequently during therapy. Discontinue rifabutin at first sign of rash; may be life-threatening. SJS, TEN, or DRESS may develop. Treat symptomatically; may recur once treatment is stopped.
Monitor for signs and symptoms of hypersensitivity reactions (hypotension, urticaria, angioedema, acute bronchospasm, conjunctivitis, thrombocytopenia, neutropenia), or flu-like syndrome (weakness, fatigue, muscle pain, nausea, vomiting, headache, fever, chills, aches, rash, itching, sweats, dizziness, shortness of breath, chest pain, cough, syncope, palpitations). If symptoms occur, discontinue rifabutin.

Lab Test Considerations:

Monitor CBC periodically during therapy. May cause neutropenia and thrombocytopenia.

Implementation ⬆ ⬇

Do not confuse rifabutin with rifapentine.
PO: May be administered without regard to meals. High-fat meals slow rate but not extent of absorption. May be mixed with foods such as applesauce. If GI upset occurs, administer with food.

Patient/Family Teaching ⬆ ⬇

Advise patient to take medication as directed. Do not skip doses or double up on missed doses. Emphasize the importance of continuing therapy even if asymptomatic.
Advise patient to notify health care professional promptly if signs and symptoms of neutropenia (sore throat, fever, signs of infection), thrombocytopenia (unusual bleeding or bruising), or hepatitis (yellow eyes and skin, nausea, vomiting, anorexia, unusual tiredness, weakness) occur.
Caution patient to avoid the use of alcohol during this therapy, because this may increase the risk of hepatotoxicity.
Instruct patient to notify health care professional immediately if diarrhea, abdominal cramping, fever, or bloody stools occur and not to treat with antidiarrheals without consulting health care professionals.
Instruct patient to report symptoms of myositis (myalgia, arthralgia), uveitis (intraocular inflammation), or hypersensitivity reactions to health care professional promptly.
Inform patient that skin, saliva, sputum, sweat, tears, urine, and feces may become brown-orange and that soft contact lenses may become permanently discolored.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected and to avoid breastfeeding during therapy.
Emphasize the importance of regular follow-up exams to monitor progress and to check for side effects.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇