In patients with renal impairment many drugs or their metabolites are excreted more slowly. It is therefore important to know what drugs will require dose reduction or are to be avoided altogether. An exception to this rule is gentamicin where careful use of a nomogram and monitoring of blood levels (peak one (1) hour after i.m. dose and trough before next dose) make its use relatively safe. (see nomogram on p. 21).

Most drugs are conveniently given at an interval equal to the half-life. If a drug is excreted exclusively by the kidney a reduction in Glomerular Filtration Rate (and hence creatinine clearance) will produce a corresponding reduction in drug excretion.

Thus if GFR falls by half the drug half-life can be expected to double; the dosage interval should therefore be doubled, while the loading dose and maintenance dose are not changed.

For practical purposes serum creatinine gives the most useful index of renal function. It does however fall with age and may not reflect the true state in the elderly, who may be assumed to have a GFR of 50ml/min even if serum creatinine is within normal limits.

Displaying 101 - 120 of 235
Drugs to be avoided or used with caution in renal failure
Active Ingredient GFR Dosage recommendations Comments
Fluvoxamine 20-Oct Start with smaller dose
Fosinopril 20-50 Start with 10mg daily See also Captopril
Frusemide 10-20 May need high doses Deafness may follow rapid i.v. injection
Gallamine 10-20 Avoid Prolonged paralysis
Ganciclovir 20-50 Reduce dose Consult data sheet
Gemfibrozil <10 Start with 900mg daily
Gentamicin see Aminoglycosides
Glibenclamide <10 Avoid Increased risk of prolonged hypoglycaemia
Gliclazide <10 Start with small dose Increased risk of hypoglycaemia
Glipizide <10 Start with small dose Increased risk of hypoglycaemia
Gliquidone <10 May need dose reduction Increased risk of hypoglycaemia
Gold (auranofin, / aurothiomalate) 20-50 Avoid Nephrotoxic
Guanethidine 10-20 Avoid Increased postural hypotenson and decrease in renal blood flow
Haloperidol see Antipsychotics
Heparin <10 Risk of bleeding incrased
Hetastarch <10 Avoid Excreted by kidney
Hexamine 20-50 Avoid Ineffective
Hydralazine 10-20 Start with small dose Increased hypotensive effect
Hydrochlorothiazide see Thiazides
Hydroflumenthiazide see Thiazides