Before taking this medication, tell your doctor or pharmacist if you are allergic to irbesartan 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: gout, kidney disease, liver disease, lupus, severe loss of body water and minerals (dehydration), 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 a serious loss of body water (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 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. This product may affect your potassium levels. Before using potassium supplements or salt substitutes that contain potassium, consult your doctor or pharmacist. 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 side effects of this drug, especially dizziness and change in the amount of urine (kidney problems). This medication is not recommended for use during pregnancy due to the risk for harm to an unborn baby. Consult your doctor for more details. (See also Warning section.) It is unknown if irbesartan passes into breast milk. Hydrochlorothiazide passes into breast milk, but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.