Priftin

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.