All three factors can be responsible for the sudden drop in blood pressure. Anesthesia itself causes changes in heart rhythms and breathing problems. Fentanyl is narcotic pain killer and is used to treat pain due to cancer. This drug is contraindicated in patients with low blood pressure because it causes weak or shallow breathing.
Niacin is Vitamin B. It also causes fainting. So, all these three drugs might contributed in sudden drop of blood pressure.
Niacin is Vitamin B. It also causes fainting. So, all these three drugs might contributed in sudden drop of blood pressure.