How they work
They inhibit the action of angiotensin converting enzyme (ACE). This prevents the renin-angiotensin loop from working, thus preventing peripheral constriction of blood vessels, and effectively lower blood pressure.
What are they used for
They are commonly used to treat hypertension and heart failure. They are the first line treatment for white people under the age of 55 with high blood pressure.
Common types and dose
- Ramipril 2.5–5mg OD (max 10mg)
- Perindopril 2-4mg OD
They can have a negative effect on renal function, and should never be used on a patient with bilateral renal artery stenosis. They also shouldn't be used with potassium sparing diuretics as this can cause hyperkalaemia.
Their key side effect is a characteristic dry tickling cough, that won't go away. If patients get this, and can't cope with it, you need to take them off the drug, probably best to try them on a angiotensin-II receptor antagonist...
Angiotensin II receptor antagonist
Also known as ARBs (angiotensin II receptor blockers), they work in a very similar way to ACE inhibitors, but cause less side effects: especially the dry cough. In time, they may replace ACE inhibitors as the first line treatment.
Common types and doses
- Losartan 50mg OD, upto 100mg in hypertension.
- Candestartan 32mg OD.
- "Effects of ACE Inhibitors, Calcium Antagonists, and Other Blood Pressure lowering Drugs " by RB Thakkar and S Oparil - Current Hypertension Reports. Volume 3, Number 3, 227-228, DOI: 10.1007/s11906-001-0043-5
- "Chronic Heart Failure: National clinical guideline for diagnosis and management in primary and secondary care." - NICE 2010. http://www.nice.org.uk/nicemedia/live/13099/50514/50514.pdf
- "Hypertension: management of hypertension in adults in primary care" - NICE 2006. http://www.nice.org.uk/nicemedia/live/10986/30114/30114.pdf
- "Clinical pharmacokinetics of angiotensin II (AT1) receptor blockers in hypertension." by ZH Israili. - J Hum Hypertens. 2000 Apr;14 Suppl 1:S73-86.