Is Effexor and Trazadone compatible and what are the side effects of the two together?

Effexor and Trazodone have similar side effects. Effexor can cause nausea, headaches, anxiety, insomnia, drowsiness, and loss of appetite. Trazodone can cause the same thing, but may cause you to gain weight and may give you muscle sorness, but helps with insomnia. Even though these are common side effects doesn't mean you will get any of them. Are you able to take the effexor in the day and trazodone at bedtime?

Hi, jean! The two drugs can be taken together under a doctor's close supervision, but serotonin syndrome is a serious condition that can occur very rarely.
Here's a link for you from the Interactions Checker at the top of this page:

https://www.drugs.com/interactions-check.php?drug_list=2228-0,2296-1524

Best wishes, WCV