rifapentine

rifapentine /rif·a·pen·tine/ (-pen´ten) a synthetic rifamycin antibiotic used in the treatment of pulmonary tuberculosis.

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rifapentine

Priftin

Pharmacologic class: Rifamycin derivative

Therapeutic class: Antitubercular

Pregnancy risk category C

Action

Inhibits RNA synthesis by blocking RNA transcription in susceptible organisms (mycobacteria and some gram-positive and gram-negative bacteria)

Availability

Tablets: 150 mg

⊘Indications and dosages

➣ Pulmonary tuberculosis (TB)

Adults: Intensive-phase treatment - 600 mg P.O. twice weekly for 2 months, with doses spaced 72 hours apart; must be given with at least one other antitubercular. Continuation-phase treatment - 600 mg P.O. once weekly for 4 months, given with another antitubercular.

Off-label uses

• Mycobacterium avium intracellulare complex infection

Contraindications

• Hypersensitivity to drug or other rifamycin derivatives

Precautions

Use cautiously in:
• hepatic disorders, porphyria
• concurrent protease inhibitor therapy for human immunodeficiency virus infection
• elderly patients
• pregnant or breastfeeding patients
• children younger than age 12.

Administration

• Know that drug is given with at least one other antitubercular.
• Expect to give drug with pyridoxine to adolescents, malnourished patients, and patients at risk for neuropathy.

Route	Onset	Peak	Duration
P.O.	Slow	5-6 hr	17-18 hr

Adverse reactions

CNS: headache, fatigue, anxiety, dizziness, aggressive behavior

CV: hypertension, peripheral edema

EENT: visual disturbances; discolored tears, sputum, and saliva

GI: nausea, vomiting, diarrhea, dyspepsia, esophagitis, gastritis, discolored feces, anorexia, pancreatitis

GU: hematuria, pyuria, proteinuria, urinary casts, discolored urine

Hematologic: anemia, thrombocytosis, hematoma, purpura, eosinophilia, neutropenia, leukopenia

Hepatic: hepatitis

Metabolic: hyperuricemia, hypovolemia, hyperkalemia

Musculoskeletal: gout, arthritis, joint pain

Skin: rash, pruritus, acne, urticaria, discolored skin and sweat

Other: edema

Interactions

Drug-drug. Amitriptyline, anticoagulants, barbiturates, beta-adrenergic blockers, chloramphenicol, clofibrate, corticosteroids, cyclosporine, dapsone, delavirdine, diazepam, digoxin, diltiazem, disopyramide, doxycycline, fentanyl, fluconazole, fluoroquinolones, haloperidol, hormonal contraceptives, indinavir, itraconazole, ketoconazole, methadone, mexiletine, nelfinavir, nifedipine, nortriptyline, oral hypoglycemics, phenothiazines, progestin, quinidine, quinine, ritonavir, saquinavir, sildenafil, tacrolimus, theophylline, thyroid preparations, tocainide, verapamil, warfarin, zidovudine: decreased actions of these drugs

Antiretroviral drugs: decreased efficacy of these drugs

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, eosinophils, lactate dehydrogenase, potassium, uric acid: increased levels

Folate, vitamin B₁₂ assays: interference with standard assays

Hemoglobin, neutrophils, platelets, white blood cells: decreased values

Patient monitoring

• Monitor CBC, uric acid level, and liver function tests. Watch for signs and symptoms of blood dyscrasias and hepatitis.
• Assess vital signs and fluid intake and output. Stay alert for hypertension and edema.
• Closely monitor nutritional status and hydration.

Patient teaching

☞ Instruct patient to immediately report fever, malaise, appetite loss, nausea, vomiting, or yellowing of skin or eyes.
• Emphasize importance of taking with companion drugs, as prescribed, to prevent growth of resistant TB strains.
• Tell patient drug may color tears, urine, and other body fluids reddish or brownish orange. Instruct him not to wear contact lenses during therapy, because drug may stain them permanently.
• Advise patient to take with meals and to minimize GI upset by eating small, frequent servings of healthy food and drinking plenty of fluids.
• Tell patient to monitor his weight and report sudden gains. Also tell him to report swelling.
☞ Instruct patient to immediately report rash or unusual bleeding or bruising.
☞ Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.