If you stop use of the Tylenol PM, it may take up to 2-4 weeks for you to adjust to falling asleep without the medication, but there should be no other problems. The current recommended
maximum daily
dosage of acetaminophen, commonly known as Tylenol, is 4000mg (4 grams) in a 24 hour period and one tablet of Tylenol PM contains 500mg of Acetaminophen and 25mg of Diphenhydramine. Therefore, if you take 2 tablets (1000mg or 1 gram) each night you are not exceeding the maximum daily dosage.