Captopril

CLINICAL USE

Angiotensin-converting enzyme inhibitor:

Hypertension

Heart failure

Post myocardial infarction

Diabetic nephropathy

DOSE IN NORMAL RENAL FUNCTION

6.25–50 mg 2–3 times daily

Diabetic nephropathy: 75–100 mg daily in divided doses

PHARMACOKINETICS

Molecular weight :217.3

%Protein binding :25–30

%Excreted unchanged in urine : 40–50

Volume of distribution (L/kg) :2

half-life – normal/ESRD (hrs) :2–3/21–32

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

20 to 50 : Start low – adjust according to response

10 to 20 : Start low – adjust according to response

<10 : Start low – adjust according to response

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD :Not dialysed. Dose as in GFR <10 mL/min

HD :Dialysed. Dose as in GFR

<10 : mL/min

HDF/high flux :Dialysed. Dose as in GFR

<10 : mL/min

CAV/VVHD :Dialysed. Dose as in GFR=10–20 mL/min

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs

Anaesthetics: enhanced hypotensive effect cinAnalgesics: antagonism of hypotensive effect and increased risk of renal impairment with NSAIDs; hyperkalaemia with ketorolac and other NSAIDs

Ciclosporin: increased risk of hyperkalaemia and nephrotoxicity

Diuretics: enhanced hypotensive effect; hyperkalaemia with potassium-sparing diuretics

Epoetin: increased risk of hyperkalaemia; antagonism of hypotensive effect

Lithium: reduced excretion, possibility of enhanced lithium toxicity

Potassium salts: increased risk of hyperkalaemia.

Tacrolimus: increased risk of hyperkalaemia and nephrotoxicity

ADMINISTRATION

Reconstition

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Route

Oral

Rate of Administration

–

Comments

Tablets may be dispersed in water

OTHER INFORMATION

dverse reactions, especially hyperkalaemia, are more common in patients with renal impairment

Effective sub-lingually in emergencies As renal function declines a hepatic elimination route for captopril becomes increasingly more significant

Renal failure has been reported in association with ACE inhibitors in patients with renal artery stenosis, post renal transplant, or in those with congestive heart failure

A high incidence of anaphylactoid reactions has been reported in patients dialysed with high-flux polyacrylonitrile membranes and treated concomitantly with an ACE inhibitor – this combination should therefore be avoided

Close monitoring of renal function during therapy is necessary in those with renal insufficiency.

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