As much as we love ACE inhibitors for their multitasking brilliance (hypertension, heart failure, diabetic nephropathy — they do it all! 💪), there are moments when prescribing them is like handing a matchstick to someone in a fireworks warehouse.
So how do you remember when not to prescribe ACE inhibitors?
Let me introduce you to a mnemonic that sounds innocent but is packed with danger: PARK.
Mnemonic: PARK — Contraindications to ACE Inhibitors
Contraindications to ACE Inhibitors Mnemonic – “PARK”
| Letter | Contraindication | Clinical Insight |
|---|---|---|
| P | Pregnancy | 🚼 ACE inhibitors are teratogenic — especially dangerous in the 2nd & 3rd trimesters. Think renal agenesis, oligohydramnios, and fetal demise. Hard pass. |
| A | Allergy/Angioedema | That one patient who got a “fat lip” on Ramipril? Not funny. Angioedema can be fatal. 😬 |
| R | Renal artery stenosis / Renal failure | ACE inhibitors dilate the efferent arteriole — and if the kidneys are already ischemic, GFR will nosedive. Classic question, classic pitfall. |
| K | Hyperkalemia (K⁺ > 5.5 mmol/L) | ACE inhibitors reduce aldosterone → potassium retention. Great for some, dangerous for many. ⚡ Watch that ECG too. |
🏥 From the Wards of Quetta…
At Sheikh Khalifa Bin Zayed Hospital, I once saw a hypertensive patient referred with persistent dry cough, but labs showed K⁺ = 6.3 and bilateral renal artery stenosis on Doppler. The prescription? Enalapril. 🤦♂️
We stopped it. His renal function improved, his potassium dropped, and the cough? Gone in 3 days.
So yeah — PARK it before you prescribe it. 🚗 😀
💡 Rapid-Fire Exam Tips (USMLE/PLAB/FCPS):
- Always check baseline renal function and electrolytes before starting an ACE inhibitor.
- Never start ACEi in bilateral RAS — single-kidney patients need even more caution.
- Cough is a side effect, not a contraindication — but angioedema is an absolute no-go.
- Pregnancy? Switch to labetalol or methyldopa.
- Consider ARBs only if angioedema was not part of the problem.
Happy learning folks! 🙂
📚 Written by:
Dr. Aurangzaib Qambrani
MBBS, PLAB, MRCP-UK
Departments: General Medicine, Gastroenterology, Cardiac Care Unit
Sheikh Khalifa Bin Zayed Hospital, Quetta
