rifapentine
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.
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, cortico-steroids, 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.