Liothyronine

CLINICAL USE

Hypothyroidism

DOSE IN NORMAL RENAL FUNCTION

Oral:

  • 10 to 20     : micrograms daily, increased to 60 micrograms in 2–3 divided dosesIV: 5–20 micrograms every 4–12 hours, or 50 micrograms initially then 25 micrograms every 8 hours, reducing to 25 micrograms twice a day

    PHARMACOKINETICS

  • Molecular weight                           :673
  • %Protein binding                           :<99
  • %Excreted unchanged in urine     : 2.5
  • Volume of distribution (L/kg)       :0.1–0.2
  • half-life – normal/ESRD (hrs)      :24–48/–

    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

  • Anticoagulants: effect of coumarins and phenindione enhanced

    ADMINISTRATION

    Reconstition

    Dissolve with 1–2 mL water for injection

    Route

    IV, oral

    Rate of Administration

    Slow bolus

    Comments

    Alkaline solution – may cause irritation if given IM

    OTHER INFORMATION

    20 mcg of liothyronine is equivalent to 100 mcg of levothyroxineProtein-losing states, such as nephrotic syndrome, will result in a decrease in total T3 and T4Thyroxine (T4) is the drug of choice in hypothyroidism, but T3 can be useful due to its rapid onset of actionElderly patients should receive smaller initial doses

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