Thanks for writing in. I am a qualified and certified cardiologist.
I read your question with diligence.
There are two issues involved here :
Deriphylline helps in bronchospasm
and one commonly prescribed drug in cardiac patients is B Blockers which can induce bronchospasm. I hope you showed your previous prescription slip to the doctor who gave you this drug.
Apart from causing increase in heart rate
an occasionally arrhythmia
this drug in short or medium term has no cardiovascular effect. Personally, I would go for inhaler with mucolytic agent
if you need to take for longish duration, which you can suggest that your doctor. In any case please take the drug for the prescribed duration. It is not OK to continue to any drug beyond the time it has been prescribed. I might have misinterpreted last sentence so; what if you actually mean : is it OK to continue the drug as long as it is prescribed by a qualified doctor when it helps you? Yes you can take it. Good Luck.
Dr Anil Grover