It is generally recommended to take medication prescribed for irritable bowel syndrome in the evening, as the side effects such as nausea are often better tolerated at night when you are at home and able to rest. However, if the side effects are severe and affecting your ability to work or function during the day, it may be worth discussing with your healthcare provider or pharmacist about possibly adjusting the timing or dosage of the medication. Nausea caused by medication can sometimes be managed with over-the-counter remedies such as Gravol, but be cautious as they may cause drowsiness. It's important to communicate with your healthcare team to find the best treatment plan for your individual needs.