2.5 Hypertension and heart failure
Angiotensin-converting enzyme inhibitors (ACE inhibitors)
Captopril (tablets) is useful for the treatment of hypertension and heart failure. It has a short half-life which may be an advantage in the early treatment of heart failure.
Enalapril (tablets) may be used for hypertension and heart failure. It has a longer duration of action than captopril, but still needs to be given twice daily for a reliable 24 hour effect.
Lisinopril (tablets) is a long-acting agent that is similar to enalapril. It can be given once daily which may assist compliance.
Ramipril (capsules, tablets) has proven efficacy in post-myocardial infarction patients with impaired left ventricular function, and as a secondary prevention in patients with a wide range of vascular disease.
PRESCRIBING POINTS FOR ACE INHIBITORS
- In hypertension, ACE inhibitors are especially useful when thiazides and beta-blockers are contra-indicated, not tolerated, or fail to control blood pressure.
- In heart failure, ACE inhibitors have been shown to improve symptoms and prolong life. They also improve outcome after myocardial infarction, particularly in patients with left ventricular dysfunction.
- Profound first-dose hypotension may occur (and is potentially serious) when ACE inhibitors are introduced to patients who are already receiving diuretics. Temporary withdrawal of the diuretic reduces the risk (see BNF 2.5.5) . The ACE inhibitor should be started at a very low dose (e.g. 6.25mg captopril) with the patient recumbent and under close medical supervision. In treating heart failure or for post-myocardial infarction, the dose should then be titrated to the highest tolerated dose, e.g. captopril 50mg three times daily, enalapril 10mg twice daily, lisinopril 30mg daily, ramipril 5mg twice daily. Ramipril 10mg once daily may be used in heart failure if blood pressure is not too low.
- Monitor symptoms, blood pressure, urea, creatinine and potassium at each dose titration.
- Treatment with ACE inhibitors can be initiated in the community but close medical supervision is required. Initiation of treatment in hospital is recommended for high-risk patients (see BNF 2.5.5).
- ACE inhibitors tend to cause potassium retention. To avoid dangerous hyperkalaemia, potassium supplements or potassium-sparing diuretics should not be used with ACE inhibitors. If spironolactone is prescribed, serum potassium must be monitored.
- ACE inhibitors should be used with care or avoided in aortic stenosis or outflow tract obstruction.
- Caution is required in patients who may have renovascular disease. ACE inhibitors are contra-indicated in patients with renal artery stenosis.
- Cough is a side-effect of all ACE inhibitors. If the problem persists, consider changing to an angiotensin-II receptor antagonist.
- ACE inhibitors and angiotensin-II receptor antagonists are contr-aindicated in pregnancy and should be avoided in patients who may become pregnant.
- In hypertension associated with diabetes, ACE inhibitors are the drugs of first choice. They reduce proteinuria and slow the deterioration in renal function.
- Every patient with heart failure as a result of left ventricular systolic dysfunction and who has no contra-indications should be prescribed ACE inhibitors.
Angiotensin-II receptor antagonists should only be used in ACE-inhibitor intolerant patients.
Candesartan (tablets) may be used in patients who show intolerance of ACE inhibitors (also see special indications below).
Losartan (tablets) may be used as an alternative to candesartan in patients who show intolerance of ACE inhibitors.
Candesartan (tablets) may be used as second-line treatment of patients with heart failure and left ventricular systolic dysfunction following treatment with an ACE inhibitor and diuretic, with or without beta-blocker. Treatment may be initiated in hospital or community, but combination therapy with an ACE inhibitor should not be initiated without specialist advice.
Irbesartan (tablets) may be used in type II diabetics with hypertension and diabetic nephropathy.
Valsartan (capsules, tablets) may be considered as a second-line alternative for use in patients post MI with LV systolic dysfuction who are intolerant of ACE inhibitors SMC No 162/05.
Glyceryl trinitrate (IV injection) is used to control hypertensive crisis and to control blood pressure in patients unable to take oral medication. It is especially useful in patients undergoing cardiovascular surgery and in patients with heart failure and/or angina.
Hydralazine (tablets, IV injection) is a vasodilator which is used in maternity hospitals for the treatment of pre-eclampsia. It is also used in combination with nitrates in the treatment of heart failure as an alternative agent to ACE inhibitors.
Methyldopa (tablets, IV injection) is a centrally-acting antihypertensive drug which is useful in pregnancy, renal failure, and as a third-line agent.
Moxonidine (tablets) is a reserve drug for patients intolerant of or resistant to other antihypertensives.
Doxazosin (tablets) has post-synaptic alpha-blocking and vasodilator properties. It is useful as a second- or third-line drug for hypertension. It may cause a rapid reduction in blood pressure after the first dose and should be introduced with caution.
Phentolamine (IV injection) is used to control blood pressure in phaeochromocytoma. It may be used intra-operatively.
Sodium nitroprusside (IV injection) is used to control hypertensive crises not responding to other drugs.