SIDE EFFECTS: Dizziness, lightheadedness, headache, blurred vision, loss of appetite, stomach upset, diarrhea, or constipation may occur as your body adjusts to the medication. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. This medication may lead to excessive loss of body water and minerals (including potassium). Tell your doctor immediately if you have any of these unlikely but serious symptoms of dehydration or mineral loss: muscle cramps or weakness, confusion, severe dizziness, unusual dry mouth or thirst, nausea or vomiting, fast/irregular heartbeat, unusual decrease in the amount of urine, fainting, seizures. Tell your doctor immediately if any of these unlikely but serious side effects occur: numbness/tingling of the arms/legs, decreased sexual ability, chest pain. Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: persistent sore throat or fever, easy bleeding or bruising, stomach/abdominal pain, persistent nausea/vomiting, yellowing of eyes/skin. A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching, swelling, severe dizziness, trouble breathing. If you notice other effects not listed above, contact your doctor or pharmacist.

PRECAUTIONS: Before taking metolazone, tell your doctor or pharmacist if you are allergic to it; or to sulfa medications; or if you have any other allergies. This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: severe kidney disease (inability to make urine or anuria). Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, untreated mineral imbalance (e.g., sodium, potassium), gout, lupus. If you have diabetes, metolazone may worsen control of blood glucose levels. Monitor your blood glucose levels regularly and inform your doctor of the results. This drug may reduce the potassium levels in your blood. Ask your doctor about adding potassium to your diet. A potassium supplement may be prescribed by your doctor. This medication may make you more sensitive to the sun. Avoid prolonged sun exposure, tanning booths or sunlamps. Use a sunscreen and wear protective clothing when outdoors. Before having surgery, tell your doctor or dentist that you are taking this medication. This drug may make you dizzy or cause blurred vision; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages. To minimize dizziness and lightheadedness, get up slowly when rising from a seated or lying position. Caution is advised when using this drug in the elderly because they may be more sensitive to its effects, especially dizziness. Metolazone should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. This drug passes into breast milk. Consult your doctor before breast-feeding.