One of the problems people have while taking a thiazide diuretic like methyclothiazide is they need to urinate often at night. If this is happening to you try taking your pills in the morning.
Another side effect you might experience is dizziness. You can minimize this by rising very slowly out of a chair or the bed and waiting for a few seconds before taking a few steps.
If the pills make you nauseated try spreading out smaller meals over the course of the day. Add some extra fiber to your diet to control constipation.
Your doctor will want you to monitor your weight because weight gain can indicate fluid retention. Keep a daily log so you can alert the doctor to any unusual fluctuations.
Be mindful of sun exposure as this drug can make your skin more sensitive to ultraviolet rays.
One of the most serious side effects is an imbalance of electrolytes, for example, losing too much potassium. Try including foods that contain good amounts of potassium such as bananas or orange juice and eat less foods containing salt. Limit your alcohol intake and check with your doctor or pharmacist before taking any new prescription, over-the-counter remedy, or dietary herbal or vitamin supplements.