Bood pressure high to low

I was taking medication for years to control my high blood pressure. whenever it was checked I was told it was fine for my age 73, (today).
Lately, I have been having bouts of falling asleep, these bouts come on without warning, I could be doing anything from eating a meal to doing a jigsaw. they can last from 1 - 45 minutes.
just to complete the picture, I had a knee replacement on Tuesday and whilst in Hospital they stopped my high blood pressure meds as the readings they were taking after the operation were very low and they only released me yesterday on the understanding I would return on Monday to have it checked again.
Whilst I realise blood pressure can often fall after an operation, I wondered if anyone else had experience of falling asleep without notice due to low blood pressure

Parkinson’s tablets make your bp go high and low I was on 7.5mg for high bp then changed tablets and my blood pressure became to low , now I’m on 2.5mg as my bp went up.its hard to find right bp as Parkinson’s drugs really don’t help .