Cyclopenthiazide.JPG

Cyclopenthiazide

CLINICAL USE

Hypertension Heart failure Oedema

DOSE IN NORMAL RENAL FUNCTION

Oedema: up to 500 mcg once dailyHeart failure: 250 mcg – 1 mg once dailyHypertension: 250–500 mcg once daily

PHARMACOKINETICS

  • Molecular weight                           :379.9
  • %Protein binding                           :No data
  • %Excreted unchanged in urine     : 100
  • Volume of distribution (L/kg)       :No data
  • half-life – normal/ESRD (hrs)      :12/Increased

    DOSE IN RENAL IMPAIRMENT

    GFR (mL/MIN)

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

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD                :Unknown dialysability. Unlikely to work
  • HD                     :Unknown dialysability. Unlikely to work
  • HDF/high flux   :Unknown dialysability. Unlikely to work
  • CAV/VVHD      :Unknown dialysability. Unlikely to work

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugsAnalgesics: increased risk of nephrotoxicity with NSAIDs; antagonism of diuretic effectAnti-arrhythmics: hypokalaemia leads to increased cardiac toxicity; effects of lidocaine and mexiletine antagonisedAntibacterials: avoid administration with lymecyclineAntidepressants: increased risk of hypokalaemia with reboxetine; enhanced hypotensive effect with MAOIs; increased risk of postural hypotension with tricyclicsAnti-epileptics: increased risk of hyponatraemia with carbamazepineAntifungals: increased risk of hypokalaemia with amphotericinAntihypertensives: enhanced hypotensive effect; increased risk of first dose hypotension with post-synaptic alpha-blockers like prazosin; hypokalaemia increases risk of ventricular arrhythmias with sotalolAntipsychotics: hypokalaemia increases risk of ventricular arrhythmias with amisulpride or sertindole; enhanced hypotensive effect with phenothiazines; hypokalaemia increases risk of ventricular arrhythmias with pimozide – avoid concomitant useAtomoxetine: hypokalaemia increases risk of ventricular arrhythmiasCardiac glycosides: increased toxicity if hypokalaemia occursCiclosporin: increased risk of nephrotoxicity and possibly hypomagnesaemiaLithium: excretion reduced, increased toxicity

    ADMINISTRATION

    Reconstition

    Route

    Oral

    Rate of Administration

    Comments

    OTHER INFORMATION

    Monitor for hypokalaemia Acts within 1–3 hours, peaks in 4–8 hours and lasts up to 12 hours