THE CONTEXT
ACE inhibitors require attention to blood pressure, renal function and potassium. Angiotensin receptor blockers offer an alternative when ACE inhibitors are not tolerated.
ACE inhibitor adverse effects
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Adverse effects include hypotension and renal impairment, especially with bilateral renal artery stenosis or pre-existing renal disease.
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Serum potassium may increase. This can offset the hypokalaemia associated with loop diuretic treatment.
Starting treatment and monitoring
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ACE inhibitors can usually be started safely in the community in stable patients without hypotension whose systolic blood pressure is over 100 mmHg.
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In other patients, it is usually advisable to withhold diuretics for 24 hours before starting a small dose of a long-acting agent, preferably at night.
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Monitor renal function and serum potassium, including a check 1–2 weeks after starting treatment.
Angiotensin receptor blockers
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Angiotensin receptor blockers block the action of angiotensin II on the heart, peripheral vasculature and kidneys.
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They produce haemodynamic benefits similar to ACE inhibitors, have comparable effects on mortality and are generally better tolerated.
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They are useful alternatives for patients who cannot tolerate ACE inhibitors. Start at a low dose and titrate upwards according to response.
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They share the serious adverse effects of ACE inhibitors, including renal dysfunction and hyperkalaemia.
Neurohumoral treatment principle
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Heart failure treatment targets detrimental renin–angiotensin and sympathetic pathways while enhancing beneficial endogenous natriuretic and vasoactive peptide systems.