Efavirenz

CLINICAL USE

Non-nucleoside reverse transcriptase inhibitor:HIV infection in combination with other antiretroviral drugs

DOSE IN NORMAL RENAL FUNCTION

600 mg once daily (tablets and capsules should be taken on an empty stomach to minimise side effects)Oral solution: 720 mg once daily

PHARMACOKINETICS

  • Molecular weight                           :315.7
  • %Protein binding                           :99.5–99.75
  • %Excreted unchanged in urine     : <1
  • Volume of distribution (L/kg)       :2–4
  • half-life – normal/ESRD (hrs)      :40–55 (multiple dosing); 52–76 (single dosing)/Unchanged

    DOSE IN RENAL IMPAIRMENT

    GFR (mL/MIN)

  • 20 to 50     : Dose as in normal renal function
  • 10 to 20     : Dose as in normal renal function
  • <10           : Dose as in normal renal function

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD                :Not dialysed. Dose as in normal renal function
  • HD                     :Not dialysed. Dose as in normal renal function
  • HDF/high flux   :Not dialysed. Dose as in normal renal function
  • CAV/VVHD      :Not dialysed. Dose as in normal renal function

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugs

  • Antidepressants: concentration reduced by St John’s wort – avoid concomitant use; concentration of sertraline reduced
  • Antifungals: itraconazole and voriconazole concentration reduced; voriconazole increases efavirenz concentration – reduce dose of efavirenz by 50% and increase dose of voriconazole to 400 mg twice daily; possibly reduces caspofungin concentration – may possibly need to increase caspofungin dose
  • Antipsychotics: possibly increased risk of ventricular arrhythmias with pimozide and sertindole – avoid concomitant use; possibly reduces aripiprazole concentration – increase aripiprazole doseAnxiolytics and hypnotics: risk of prolonged sedation with midazolam – avoid concomitant use
  • Antivirals: saquinavir concentration significantly reduced; concentration of amprenavir, darunavir, indinavir, lopinavir and atazanavir reduced – increase atazanavir dose; concentration reduced by nevirapine; monitor LFTs when used in combination with ritonavir
  • Ciclosporin: concentration of ciclosporin possibly reduced
  • Ergot alkaloids: risk of ergotism – avoid concomitant use
  • Grapefruit juice: concentration possibly increased

    ADMINISTRATION

    Reconstition

    –

    Route

    Oral

    Rate of Administration

    –

    Comments

    –

    OTHER INFORMATION

    Induces its own metabolism Metabolised by CYP450 3A4 and 2B6 systemsMonitor cholesterol levels as increases of

  • 10 to 20

    • % in total cholesterol have been reportedHalf-life of 10 hours in haemodialysis patients has been reported

  • Bioavailability of oral solution is less than that for capsules or tablets – therefore not interchangeable
    • Tags:

    Related News

    ffddfd

    Hyperlipidemia