Does anyone get nightmares from opiates? Starting last weekend after around a 10 day break I've been taking 60-90mg of oxycodone and small amounts of codeine (around 90-120mg) each day. Whenever I fall asleep I have bad dreams about dieing that feel real up til the moment I wake up. I'm taking around 20mg of doxylamine with the codeine, and small amounts of benadryl to potentiate the oxycodone. I've been taking opiates and antihistamines off and on for months but these nightmares only started last weekend after around a 10 day break.