SIDE EFFECTS: See also Warning section. Dizziness, lightheadedness, headache, or upset stomach may occur as your body adjusts to the medication. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. To lower your risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. This product may cause your body to lose too much water and salt (dehydration). Tell your doctor right away if you notice any symptoms of dehydration, such as unusual dry mouth/thirst, fast heartbeat, or dizziness/lightheadedness. Tell your doctor right away if any of these unlikely but serious side effects occur: fainting, muscle cramps/weakness, slow/fast/irregular heartbeat, decrease in vision, eye pain, signs of kidney problems (such as change in the amount of urine). A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

HOW TO USE: Take this medication by mouth as directed by your doctor, usually once daily in the morning with or without food. It is best to avoid taking this medication within 4 hours of your bedtime to prevent having to get up to urinate. If you also take certain drugs to lower your cholesterol (bile acid-binding resins such as cholestyramine or colestipol), take this product at least 4 hours before or at least 4 to 6 hours after these medications. The dosage is based on your medical condition and response to treatment. Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day. Keep taking this medication even if you feel well. Most people with high blood pressure do not feel sick. Tell your doctor if your condition does not improve or if it worsens (for example, your blood pressure readings increase).

PRECAUTIONS: Before taking this medication, tell your doctor or pharmacist if you are allergic to triamterene or hydrochlorothiazide; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: diabetes, gout, high level of potassium in the blood, kidney disease (including kidney stones), liver disease, lupus, skin cancer. This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis). Severe sweating, diarrhea, or vomiting can increase the risk for lightheadedness or dehydration. Report prolonged diarrhea or vomiting to your doctor. To prevent dehydration, drink plenty of fluids unless your doctor directs you otherwise. If you have diabetes, this product may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Your doctor may need to adjust your diabetes medication, exercise program, or diet. This medication may affect your potassium levels. Before using potassium supplements or salt substitutes that contain potassium, consult your doctor or pharmacist. This medication may make you more sensitive to the sun. It may also increase your risk for skin cancer, especially if you take it for a long time. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned, have skin blisters/redness, or notice new or changed moles/skin lesions. Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). Older adults may be more sensitive to the effects of this drug, especially dizziness, or high blood potassium levels. During pregnancy, this medication should be used only when clearly needed. It may harm an unborn baby. Discuss the risks and benefits with your doctor. It is unknown if triamterene passes into breast milk. Hydrochlorothiazide passes into breast milk, but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: See also How to Use and Precautions sections. Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug include: dofetilide, lithium, other drugs that may increase potassium levels (such as spironolactone, amiloride, cyclosporine). Some products have ingredients that could raise your blood pressure or worsen your swelling. Tell your pharmacist what products you are using, and ask how to use them safely (especially cough-and-cold products, diet aids, or NSAIDs such as ibuprofen/naproxen). This medication may interfere with certain laboratory tests (including parathyroid function), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe dizziness, fainting.