Propranolol and triptans?

I don't see any possible interactions. Propranolol has a very low affinity to 5HT 1B (one of the receptors triptans act on).

There is one triptan that shouldn't be used in combination with propranolol: Rizatriptan (EDIT: actually it says: "if you use propranolol and rizatriptan, your daily rizatriptan dose should be not more than 10mg")

Metoprolol could be used alternatively, as it's also used in the prophylaxis of migraine.