Venlafaxine
Venlafaxine is a serotonin and noradrenaline reuptake inhibitor. It blocks the reuptake of both transmitters, so more of each remains available at the synapse, with the noradrenergic effect becoming more prominent as the dose rises. It is used in depression and in anxiety disorders.
It is taken with food, usually in the morning, and the therapeutic effect builds over weeks. Blood pressure can rise, more so at higher doses, so it is monitored before and during treatment; light-headedness on standing can also occur, and blood sodium can drop and is worth monitoring. Sumatriptan and tramadol both add serotonergic activity on top of it, and tramadol additionally lowers the seizure threshold. Missed doses are felt quickly with this drug, so it is not stopped abruptly and changes are made with the prescriber.
Fainting or persistent dizziness on standing, and confusion, weakness or unsteadiness that could reflect low sodium, should be assessed. Agitation with fever, sweating, tremor or a fast heartbeat after adding a triptan or tramadol, and severe dizziness or electric-shock sensations after stopping, are reasons to see a doctor.
Reference information, not medical advice. Discuss any change with your doctor.