He used his GTN spray as usual — so why did he collapse?
Nitrates and sildenafil widen blood vessels by the same route. Together, blood pressure can drop dangerously low.
Select any card for the reasoning, what to watch for and an exam tip.
The puzzle
A man with angina keeps a GTN spray for chest pain. He has started taking sildenafil that he bought online, and hasn’t told his GP. A few hours after a dose he gets chest pain, uses his spray, and collapses.
The answer, step by step
Who is most at risk
- Men with angina on GTN, isosorbide mononitrate or nicorandil.
- Anyone who buys erection tablets privately or online.
- Recent heart attack, stroke or unstable angina: sildenafil is contra-indicated.
- Low blood pressure: avoid sildenafil if the systolic is below 90.
What to do
Key takeaway
Never combine a nitrate with sildenafil or another PDE5 inhibitor: the BNF says avoid. Ask every man with angina about erection tablets, including ones bought online, and every buyer of sildenafil about chest pain medicines.