hi,
Thank you for posting your query in Health Care Magic, i understand your concern.
The drug Dextramphetamine could have a few side effects amonsgt which
premature ejaculation is one, though it is just about 1 in 1000 possibility it could still be a uncommon cause.
If you are taking the drug for psychological causes like
depression,
anxiety or
insomnia these conditions itself may be the cause of your premature ejaculation.
Its good if you consult with a physician who can ask a few details of your sex-history and do a relevant physical examination to confirm the cause of premature ejaculation.
Also stop smoking and alcohol if you are on it.
A few drugs like fluoxetine/
paroxetine called as SSRI's can be of help, but take them only after you consult your doctor.
Hope this helps and answers your query satisfactorily.
Write back to me if you have further queries.
Take care and wish you good health.