II. Mechanism

  1. Semisynthetic, long acting Rifamycin derivative active against Mycobacteria
    1. Rifamycin is produced by Streptomyces mediterranei
  2. Rifamycins inhibit Bacterial DNA-dependent RNA Polymerase, blocking Bacterial RNA formation and transcription

IV. Contraindications

  1. Children under age 2 years
  2. Latent Tuberculosis with suspected resistance to Isoniazid or Rifampin
  3. HIV patients on Antiretrovirals (due to lower drug levels and risk of resistance)
  4. Porphyria

V. Dosing

  1. General
    1. Take Rifapentine with food
    2. Rifapentine tablets and mixed with a small amount of food
  2. Active Tuberculosis
    1. See Active Tuberculosis
    2. Part of multi-drug regimen; high risk of drug resistance Tb if used alone
    3. Adults (and children age >12 years)
      1. Give 600 mg orally twice weekly for 2 months then once weekly for 4 months
  3. Latent Tuberculosis (age >2 years)
    1. See Latent Tuberculosis
    2. Combination for 12 weeks of BOTH Isoniazid once weekly AND
    3. Weight-based Rifapentine
      1. Weight 10 to 14 kg: Rifapentine 300 mg orally once weekly
      2. Weight 14 to 25 kg: Rifapentine 450 mg orally once weekly
      3. Weight 25 to 32 kg: Rifapentine 600 mg orally once weekly
      4. Weight 32 to 50 kg: Rifapentine 750 mg orally once weekly
      5. Weight >50 kg: Rifapentine 900 mg orally once weekly

VI. Adverse Effects

  1. See Rifampin
  2. Hyperuricemia
  3. Body secretion discoloration (orange to brown)
    1. Discolors urine, dentures and Contact Lenses
  4. Hepatotoxicity (uncommon)
    1. See Rifampin for risks and monitoring
  5. Thrombocytopenia
  6. Neutropenia (rare)
  7. Porphyria exacerbation

VII. Safety

  1. Unknown safety in Lactation
  2. Pregnancy Category C (minimal safety data)
    1. Risk of Hemorrhagic Diathesis of the Newborn (Neonatal Vitamin K Deficiency)
    2. Give Vitamin K 10 mg IM to newborns

VIII. Drug Interactions

  1. See Rifampin
  2. Strong CYP3A4 Inducer
  3. CYP2C9 Inducer
  4. Oral Contraceptives (as well as Contraceptive Patch, Estrogen Ring)
    1. Consider alternative contraceptives (e.g. Depo Provera, IUD)
  5. Antiretroviral therapy (HIV)
    1. Protease Inhibitors (reduced drug level and efficacy)

IX. Monitoring

  1. Baseline labs
    1. Liver Function Tests
    2. Complete Blood Count
  2. Periodic labs
    1. See Rifampin for monitoring indications

XI. References

  1. (2019) Presc Lett, Resource #350309, Tuberculosis Treatment in Adults: FAQ
  2. (2012) Med Lett Drugs Ther 10(116): 29-36
  3. (2011) MMWR Morb Mortal Wkly Rep 60(48): 1650-3 [PubMed]
  4. Hartman-Adams (2014) Am Fam Physician 89(11): 889-96 [PubMed]

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Cost: Medications

priftin (on 1/3/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
PRIFTIN 150 MG TABLET $4.23 each