Lifestyle

Dizziness When You Stand, Muscle Cramps, or Less Urine on a Water Pill Can Be Signs to Tell Your Doctor. What Older Adults Should Know

By Mike Harper · November 9, 2026

If you take a water pill for blood pressure or swelling, some of its side effects are worth knowing about ahead of time.

This piece looks at furosemide, a widely used water pill also sold under the brand name Lasix, using the MedlinePlus drug information page from the National Library of Medicine. If you take a different water pill, check the information that came with your own prescription.

According to MedlinePlus, furosemide is used alone or with other medicines to treat high blood pressure, and to treat edema, which is excess fluid held in body tissues from various medical problems. It belongs to a class of drugs called diuretics. It works by causing the kidneys to get rid of unneeded water and salt.

Dizziness when you get up. MedlinePlus says furosemide may cause dizziness, lightheadedness and fainting when you get up too quickly from lying down. This is more common when you first start the medicine. Its suggestion is to get out of bed slowly, resting your feet on the floor for a few minutes before you stand. Alcohol can add to these effects.

Side effects to mention if they are severe or do not go away. MedlinePlus lists frequent urination, blurred vision, headache, constipation and diarrhea.

Side effects that need a call to the doctor right away. MedlinePlus says some side effects can be serious, and that if you have any of these, you should call your doctor immediately or get emergency care:

Decreased urination, dry mouth, thirst, nausea, vomiting, weakness, drowsiness, confusion, muscle pain or cramps, or a rapid or pounding heartbeat.

Fever.

Ringing in the ears or loss of hearing.

Itching, rash, hives, blisters or peeling skin, or trouble breathing or swallowing.

Yellowing of the skin or eyes.

Some of these, such as thirst, muscle cramps, weakness and confusion, are easy to blame on a hot day, a long walk or simply getting older. That is part of why it helps to know they appear on the list.

Over-the-counter pain relievers. MedlinePlus says aspirin and other salicylates, and nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen, may interact with furosemide. It advises telling your doctor and pharmacist if you take them, and not starting any of them while on furosemide without talking with your health care provider.

Food instructions. If your doctor prescribes a low-salt diet or tells you to eat more potassium-rich foods such as bananas, prunes, raisins and orange juice, MedlinePlus says to follow those instructions carefully.

Checkups and lab work. MedlinePlus says to keep all appointments with your doctor and the laboratory, that your blood pressure should be checked regularly, and that blood tests should be done occasionally.

Just as important is what not to do. MedlinePlus says to take furosemide exactly as directed, not to take more or less than prescribed, and not to stop taking it without talking to your doctor, even if you feel well. The medicine controls high blood pressure and edema but does not cure them.

A practical step is to keep a written list of every prescription and over-the-counter medicine, vitamin and supplement you take, which MedlinePlus recommends bringing to each visit. If you notice dizziness when you stand, new cramps, or a change in how often you urinate, write down when it started and bring it up with your doctor or pharmacist. Only they can tell whether it is related to the medicine and what, if anything, should change.

This article is for general information and is not medical advice. Do not stop or change any medicine without talking to your doctor. This article was produced with the assistance of AI and fact-checked against the sources cited by LightWave Reports.