CLINICAL USE

Immunosuppressant:Prophylaxis of transplant allograft rejection

DOSE IN NORMAL RENAL FUNCTION

6 mg loading dose followed by 2 mg daily, adjusted according to levels – see ‘Other Information’

PHARMACOKINETICS

  • Molecular weight                           :914.2
  • %Protein binding                           :92
  • %Excreted unchanged in urine     : 2.2
  • Volume of distribution (L/kg)       :4–20
  • half-life – normal/ESRD (hrs)      :48–78/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                :Unlikely to be dialysed. Dose as in normal renal function
  • HD                     :Not dialysed. Dose as in normal renal function
  • HDF/high flux   :Unknown dialysability. Dose as in normal renal function
  • CAV/VVHD      :Unlikely to be dialysed. Dose as in normal renal function

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugs

  • Antibacterials: concentration increased by clarithromycin and telithromycin – avoid; concentration of both drugs increased with erythromycin; concentration reduced by rifampicin and rifabutin – avoid
  • Antifungals: concentration increased by itraconazole, ketoconazole, miconazole, posaconazole and voriconazole
  • Antivirals: concentration possibly increased by atazanavir and lopinavir
  • Calcium-channel blockers: concentration increased by diltiazem; concentration of both drugs increased with verapamil
  • Ciclosporin: increased absorption of sirolimus – give sirolimus 4 hours after ciclosporin; sirolimus concentration increased; long-term concomitant administration may be associated with a deterioration in renal function
  • Grapefruit juice: concentration of sirolimus increased – avoid concomitant useMycophenolate: concomitant use of mycophenolate and sirolimus increases plasma levels of both sirolimus and mycophenolic acid

    ADMINISTRATION

    Reconstition

    Route

    Oral

    Rate of Administration

    Comments

    OTHER INFORMATION

    Aim for trough levels of 4–12 ng/mL where sirolimus is used in combination with low dose ciclosporinIn cases of delayed graft function or where a calcineurin inhibitor is not tolerated or contraindicated, sirolimus may be used with steroids alone. A loading dose of 10–15 mg may be given, followed by maintenance dose of 3–6 mg daily and adjust according to levels. Aim for trough levels of 8–20 ng/mLMay be used in combination with MMF, but can lead to delayed wound healing post surgery. Sirolimus can increase levels of mycophenolate mofetil leading to anaemiaSome centres successfully using level- controlled sirolimus in conjunction with low dose tacrolimus
    Anecdotally, has been used for encapsulating sclerosing peritonitis in a CAPD patient at Guy’s Hospital, London. Acts by interfering with various growth factors and their effect on impairing wound healing.
    Pneumonitis appears to be more common with sirolimus than initially thought, especially if the trough levels are on the high side.
    If changing from tablets to solution, give the same dose and monitor trough levels 1–2 weeks laterTablet has a 27% increased bioavailability compared with the solutionSirolimus has been associated with anaphylactic/anaphylactoid reactions, angioedema and hypersensitivity vasculitis.

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