A painkiller after a fall — why is he now sweating, shaking and agitated?
Tramadol is not just an opioid: it also boosts serotonin. Added to an SSRI, it can tip into serotonin toxicity.
Select any card for the reasoning, what to watch for and an exam tip.
The puzzle
A man has taken sertraline for depression for a year. After a fall he is prescribed tramadol for a painful shoulder. The next day he is restless, sweating and shaking, his legs keep jerking, and he has diarrhoea.
The answer, step by step
Who is most at risk
- Anyone on an SSRI, an SNRI such as venlafaxine, or an MAOI who is given tramadol.
- Dose increases, or another serotonergic drug added.
- Epilepsy, or anyone prone to seizures.
- Older people: both drugs also cause hyponatraemia and drowsiness.
What to do
Key takeaway
Tramadol plus an SSRI can cause serotonin toxicity: agitation, sweating, tremor, jerking muscles and fever. Choose another painkiller where you can, warn about the signs, and stop both drugs if they appear.