24

Metabolic consequences of antihypertensive therapy

DRUG REACTIONS

Adverse metabolic effects have been associated with antihypertensive drugs, especially diuretics and ~-blockers. The fact that newer classes of drugs such as a -blockers, calcium antagonists and ACE inhibitors have few metabolic adverse effects has important clinical implications for antihypertensive therapy, in the opinion of Drs Harry Preuss and James Burris from the US.

There is concern that the metabolic effects of thiazide diuretics and l3-blockers in particular may adversely influence long-term cardiac risk and thus offset some of the benefit attributable to their antihypertensive effects. However, there is still no definitive proof of the clinical consequences of these metabolic effects.

Differing metabolic profiles Diuretics can cause electrolyte disturbances

(hypokalaemia and hypomagnesaemia) and metabolic disturbances such as increases in circulating plasma cholesterol levels, hyperuricaemia and abnormal glucose/insulin metabolism. Many ~-blockers also adversely influence glucose/insulin and lipid metabolism.

In contrast, a-blockers tend to benefit the lipid profile while affecting neither glucose/insulin metabolism nor electrolytes. Calcium antagonists are metabolically neutral; ACE inhibitors are lipid neutral and may even favourably influence glucose/insulin metabolism.

Implications for treatment In order to overcome many of the adverse effects of

diuretics, Drs Preuss and Burris suggest that a lower dosage or a different diuretic may be used. However, not all agree that use of low doses of diuretics can avoid the deleterious effect of such agents on coronary artery disease risk. Drs Preuss and Burris say that indapamide may accomplish many of the beneficial effects of thiazides without causing many of the adverse effects. Preuss HG. Bwris1F. Adverse metabolic effecu of antihypertensive drugs; implications for tteatIDCIIt. Drug Safety 14: 355·364, Jun 1996 _ .....

Inpharma-13 Ju118M No. 1045 0156-270319611045-000241$01.cxf AdlalnternatloNiI Limited 18M. All righta ~