Some common side effects of this drug include: Dizziness, Lightheadedness, Weakness, Muscle cramps, Upset stomach, Diarrhea If any of the conditions start to get worse, let your doctor know immediately. To avoid getting dizzy or lightheaded, rise from your sitting or lying position very slowly. Keep in mind that your doctor has prescribed you this medication because its benefits to you are greater than the risk of side effects. Many people who use this medication do not have serious side effects. Since this drug is diuretic, it can cause serious loss of body water, salts, and minerals. If you notice any of the following symptoms, notify your doctor immediately: Dehydration, Unusual decreased urination, Dry mouth, Fast or irregular heartbeat, Dizziness, Easy bruising, Vertigo, Decreased hearing, Bloody stool, Stomach or abdominal pain