ACE Inhibitors: The Dispensing Safety Checklist

📋 First Dispense Essentials

Mandatory items to issue

• Before supply, ask the patient if they have ever had angioedema (swelling of the face, lips, tongue, or throat) with an ACE inhibitor previously. If yes, do not supply and refer to the prescriber immediately. Previous ACE-inhibitor-associated angioedema is a contraindication to future ACE inhibitor use. [5]
• Check with the patient, or from available prescribing records, that baseline blood tests have been completed before starting: eGFR (estimated glomerular filtration rate) or creatinine, potassium, and sodium. [1, 4] ACE inhibitors should not normally be initiated if potassium is above 5.0 mmol/L. [4]
• Provide or confirm sick day rules advice. Ensure the patient knows to temporarily stop their ACE inhibitor during any acute illness causing dehydration or poor fluid intake, including vomiting, diarrhoea, fever with sweating, or any illness where they cannot eat or drink normally. Restart when eating and drinking normally for 24 to 48 hours, or sooner if advised by the prescriber or specialist team. Supply a sick day rules card if one is available locally.
• Counsel on first-dose hypotension. Blood pressure may fall significantly after the first dose, particularly in patients with heart failure, volume depletion, or those on high-dose diuretics. Advise taking the first dose at bedtime and rising slowly after sitting or lying down.

Baseline clinical checks

• eGFR or creatinine: required at baseline. A small rise in creatinine after starting is expected and acceptable. If creatinine rises by more than 30% or eGFR falls by more than 25%, recheck blood results and investigate before acting. If deterioration persists, contact the prescriber; dose reduction or discontinuation may be needed. This pattern may indicate renal artery stenosis or significant renal impairment. [4]
• Potassium: ACE inhibitors reduce aldosterone secretion, causing potassium retention. Do not normally initiate if potassium is above 5.0 mmol/L. [4] Risk of dangerous hyperkalaemia increases significantly when combined with potassium-sparing diuretics, spironolactone, or NSAIDs (non-steroidal anti-inflammatory drugs).
• Blood pressure: record baseline blood pressure. First-dose hypotension is a particular risk in heart failure, volume depletion, or high-dose diuretic use. Seek specialist advice before starting if systolic blood pressure is below 90 mmHg.
• Consider specialist advice before starting in patients with eGFR below 30 mL/min/1.73m2, known renovascular disease, or hyponatraemia (sodium below 130 mmol/L).

Key risks and lifestyle traps

• NSAIDs (including ibuprofen, naproxen, analgesic-dose aspirin, and combination cold and flu products containing NSAIDs) reduce the renal blood-flow effects of ACE inhibitors, worsen kidney function, and increase the risk of hyperkalaemia. Do not supply OTC NSAIDs to a patient on an ACE inhibitor without a pharmacist or prescriber check. Advise patients not to buy ibuprofen or other NSAIDs without checking first.
• Potassium-sparing diuretics (amiloride) and aldosterone antagonists (spironolactone, eplerenone): combination with ACE inhibitors increases the risk of hyperkalaemia substantially. [2] Monitor potassium closely. Combination therapy requires careful monitoring and would not normally be initiated if baseline potassium exceeds 5.0 mmol/L.
• Salt substitutes and potassium supplements: many salt substitutes contain potassium chloride and can cause dangerous hyperkalaemia when combined with ACE inhibitors. Patients should be advised not to use potassium-containing salt substitutes without prescriber advice.
• Trimethoprim and co-trimoxazole: both block renal tubular potassium excretion and can cause significant hyperkalaemia in patients taking ACE inhibitors, particularly in older adults or those with impaired renal function. Alert the prescriber if trimethoprim is being added to an ACE inhibitor.
• Lithium: ACE inhibitors reduce lithium excretion, raising lithium levels and increasing toxicity risk. If an ACE inhibitor is started or stopped in a patient taking lithium, monitor lithium levels closely.
• Combined ACE inhibitor and ARB (angiotensin receptor blocker) therapy is not routinely recommended. The combination increases the risk of acute kidney injury and hyperkalaemia without meaningful additional benefit for most patients.
• Dry cough affects approximately 5 to 20% of patients and is more common in women and people of East Asian origin. It is frequently missed as a drug side effect. If a patient reports a persistent dry cough, refer to the prescriber; a switch to an ARB usually resolves it.
• Angioedema is rare but life-threatening. It can occur at any time during treatment, including years after starting. It is more common in people of African and Caribbean descent. [5] If angioedema involves the tongue, throat, voice, or breathing, call 999 immediately. Do not advise self-transfer to A&E. ACE inhibitors must be stopped immediately and never restarted after angioedema.

First dispense script

🔄 Repeat Dispense Screen

Mandatory documentation

• Record the dose dispensed on every occasion. Note any recent dose changes.
• Record whether renal function and electrolyte monitoring appears current. Document any interventions made if monitoring appears overdue.
• Note any newly added interacting medicines, particularly NSAIDs, potassium-sparing diuretics, or spironolactone.

Ongoing clinical checks

• Heart failure: eGFR or creatinine, potassium, and sodium within 1 to 2 weeks of starting or dose change (within 5 to 7 days if risk factors such as age over 60, chronic kidney disease, or diabetes). Then monthly for 3 months, then every 6 months. Repeat at any time the patient is acutely unwell. [4]
• Hypertension and post-myocardial infarction: eGFR, potassium, and sodium within 1 to 2 weeks (7 days if risk factors). Then annually. Blood pressure within 1 month of starting. [1, 4]
• Check for newly prescribed NSAIDs, potassium supplements, or potassium-sparing diuretics at every dispense.
• If the patient is on lithium, confirm whether lithium levels have been checked since the ACE inhibitor was started or most recently adjusted.

Lifestyle and surgical alerts

• Sick day rules: withhold the ACE inhibitor during any dehydrating illness. Restart when eating and drinking normally for 24 to 48 hours, or sooner if the prescriber or specialist team advises. Patients taking multiple SADMAN medicines (Sulphonylureas, ACE inhibitors and ARBs, Diuretics, Metformin, and NSAIDs including analgesic-dose aspirin at doses of 300 mg or above; low-dose antiplatelet aspirin 75 mg should not be stopped under sick day rules unless specifically advised) are at particularly high risk of acute kidney injury during illness.
• Avoid NSAIDs, including OTC ibuprofen, unless specifically agreed with the prescriber.
• Patients should rise slowly from sitting or lying to reduce the risk of dizziness from low blood pressure.
• Pregnancy: ACE inhibitors should be avoided in pregnancy and are teratogenic in the second and third trimesters. Women of childbearing potential who are planning pregnancy should discuss alternative medications with their prescriber. If pregnancy occurs, stop the ACE inhibitor as soon as possible and refer urgently to the prescriber for an alternative antihypertensive. [3, 6]
• Breastfeeding: ACE inhibitor use during breastfeeding should be a prescriber-led decision. Advice on individual medicines should be sought from the prescriber or a specialist medicines in pregnancy and breastfeeding service. [7]

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