Hydrochlorothiazide is a medication prescribed for a variety of conditions. It was approved by the FDA in 1959. It is used most often to treat high blood pressure. It is also prescribed to treat edema, which is excessive fluid accumulation in the body. As with most medications, hydrochlorothiazide side effects can be serious or just irritating, and many patients experience no side effects at all.
Generally, doctors will only prescribe a medication if they feel that the positive aspects of the treatment outweigh any potential negatives. Keep this in mind as you review hydrochlorothiazide side effects. If you are taking or planning to take hydrochlorothiazide, learn about the possible side effects and know when to contact your physician.
What Is Hydrochlorothiazide?
Hydrochlorothiazide is a medication that is available as a generic and a brand name drug. The brand name is Microzide. Hydrochlorothiazide is part of a class of drugs known as diuretics, or "water pills." Diuretics cause you to make more urine, which helps your body eliminate extra salt and water. Hydrochlorothiazide is available as a tablet, capsule, or solution you take by the mouth.
Why Do Doctors Prescribe It?
Treat High Blood Pressure
Doctors commonly prescribe hydrochlorothiazide to treat high blood pressure. The purpose of lowering blood pressure in patients is to help prevent heart attacks, strokes, and kidney problems.
Doctors also prescribe Hydrochlorothiazide to reduce excessive fluid accumulation in the body (edema) that has been caused by heart failure, liver damage, kidney failure, nephrotic syndrome (a kidney disorder that causes the body to excrete too much protein in your urine) and certain medications, especially corticosteroids.
While hydrochlorothiazide may be used to treat edema in cirrhosis of the liver, there are more effective diuretics that are used in that case.
Treat Kidney Stones
Lastly, it can be used to treat kidney stones by decreasing the amount of calcium that the kidneys excrete. That decreases the amount of calcium in the urine that may form stones.
How to Take Hydrochlorothiazide
There are three forms of hydrochlorothiazide: tablet, capsule, and solution, and all are taken orally. It is OK to crush the tablets. Your dose, form, and how often you take it will be determined by your physician and will depend on your age, the condition being treated, the severity of your condition, any other medical conditions you have, and how you react to the first dose.
You may take the medication with or without food. It's best to take the drug in the morning because you may urinate more frequently. Taking it at night may cause you to need to get up at night to use the bathroom, thus disrupting your sleep.
Since hydrochlorothiazide can cause dizziness, note that alcohol or marijuana use can make you dizzier. Don't drive, use machinery, or do anything that needs alertness until you know you can perform those tasks safely. Limit alcoholic beverages and talk to your doctor if you use marijuana.
Do not take this drug if you are allergic to medications containing sulfonamide; instead discuss this with your physician to consider an alternate treatment.
How Does It Work?
It isn't known exactly how hydrochlorothiazide works. It belongs to a class of drugs called thiazide diuretics. Hydrochlorothiazide is thought to work to remove excess salt and water from your body. By removing the excess salt and water, the heart does not have to work as hard to pump blood. This, in turn, lowers high blood pressure levels and reduces swelling/excessive fluid accumulation in the body.
Unlike many other medications, hydrochlorothiazide does not cause drowsiness. It also effectively lowers excess salt and water levels and lowers the blood pressure.
If you are taking or plan to take hydrochlorothiazide, You may experience the following side effects:
More Common Hydrochlorothiazide Side Effects
The most common hydrochlorothiazide side effects, while uncomfortable or irritating, are probably not serious or life-threatening. However, contact your physician if they persist and are very difficult to live with.
Lowered Blood Pressure
Some patients report lower than normal blood pressure. This can especially occur when standing up quickly after sitting or lying down. So take care and be aware of the possibility of dizziness when you change position, especially when you first start taking the medication. This blood pressure change may cause you to lose your balance and feel light headed. So get up slowly when rising from a sitting or lying position.
Some hydrochlorothiazide side effects reported include dizziness and lightheadedness. Again, this might be due to the reduction in blood pressure. If you experience either of these symptoms, be sure to sit down to avoid falling.
Another known side effect is a headache. This may occur as your body adjusts to the medication.
You may experience a sensitivity to light and/or a rash caused by sunlight. Consider covering up or using sunscreen when you go outside when using this medication.
Digestive type hydrochlorothiazide side effects have been reported such as upset stomach, diarrhea, loss of appetite, stomach cramps, nausea, and vomiting.
Sexual Side Effects
Some patients reported erectile dysfunction (trouble getting or keeping an erection).
Some medication users report weakness, and others report hand, leg, and feet tingling.
If these more common hydrochlorothiazide side effects are mild, they may go away within a few days or a couple of weeks as your body adjusts to the medication. However, if they are more severe or don't stop, talk with your doctor or pharmacist.
Rare but Serious Hydrochlorothiazide Side Effects
Like most all medications, hydrochlorothiazide can cause serious side effects in some patients. It must be noted, however, that these are rare and unlikely. If you experience serious side effects, it is important to call your doctor immediately. If the symptoms feel life-threatening or you think you're having a medical emergency, call 911. Listed below are some serious hydrochlorothiazide side effects.
One of the very rare but life-threatening hydrochlorothiazide side effects is anaphylaxis. Symptoms may vary and can include hives, swelling of the tongue, vomiting, and in the most severe cases, shock. Seek medical attention immediately if you have any of these symptoms.
Hydrochlorothiazide may result in electrolyte disturbances caused by the loss of too much body water (dehydration) and salt/minerals. Symptoms of electrolyte imbalance, dehydration or mineral loss include extreme thirst, dry mouth, extreme muscle cramps or weakness, restlessness, seizures, lower than normal blood pressure, changes in heartbeat (slow, fast, or irregular), confusion, and decreased urination. Your physician should check your fluid and electrolytes when you are taking the medication.
Severe Skin Reactions
Contact your physician if you experience severe skin reactions such as Stevens-Johnson syndrome (a rare, serious disorder of the skin and mucous membranes) or exfoliative dermatitis. These conditions have symptoms such as a painful skin rash, skin peeling, and blisters, fever, and/or mouth sores.
Another severe side effect reported is kidney failure. Kidney failure has symptoms such as weakness, shortness of breath, tiredness, confusion, abnormal heart rate or chest pain, producing less urine than normal, and increased swelling in your legs, ankles, or feet. Hydrochlorothiazide may aggravate kidney dysfunction by lowering blood potassium, sodium, and magnesium levels. The medication must be used with caution by patients with kidney disease.
Since blood uric acid levels can increase during hydrochlorothiazide treatment, some individuals may experience an acute gout episode, whose symptoms include a sudden, severe attack of pain, swelling, redness, and tenderness in the joints (often the joint at the base of the big toe is affected). If this happens, seek medical attention.
Blurred vision and glaucoma may occur, so if you experience symptoms such as eye pain and difficulty seeing, tell your doctor right away.
Rarely, pancreatitis (sudden inflammation of the pancreas) or jaundice (presented as a yellow coloring of the skin or eyes caused by too much bilirubin in the body) may occur as a side effect of this medication. And this medication (being a thiazide diuretic) may increase glucose (blood sugar) levels and precipitate diabetes. Seek medical attention if these are a concern.
There are a few known drugs that have adverse interactions to note. Hydrochlorothiazide reduces the elimination of the medication lithium by the kidneys and can lead to lithium toxicity. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen may reduce blood pressure, thus lowering the effectiveness of hydrochlorothiazide.
Hydrochlorothiazide might elevate blood sugar levels, so diabetes medications may need to be adjusted. If you use corticosteroids, talk with your doctor about the risks of changes in blood potassium and other electrolytes. Check with your doctor if you take cholestyramine and colestipol as those drugs bind to hydrochlorothiazide and reduce its absorption. Also, consult your physician if you take dofetilide as it may interact with hydrochlorothiazide.
Remember that most doctors only prescribe medications if they believe the benefits outweigh the potential for side effects. Serious hydrochlorothiazide side effects are rare. However, if you experience any of the symptoms of serious side effects listed above, seek medical attention immediately. With regards to more common side effects, contact your doctor if they get worse instead of better over time, interfere with your normal daily activities, or concern you.