Mersyndol is a brand name
for the combination of acetaminophen, codeine, and doxylamine used
for relief of headache, cold symptoms, neuralgia, and muscular aches/pain."
The codeine is an opiate and highly addictive! The Doxylamine is listed as an antihistamine - something that help many people sleep. Stopping this suddenly could be the cause of your itching and insomnia. Stopping the codeine could be the cause of your nausea, anxiety, depression and again, insomnia.