Brand Name:Apo-Hydro, Novo-Hydrazide

Prescription needed: Yes

What is this drug used for?

Hydrochlorothiazide is most commonly used to treat high blood pressure but it may also be used for other conditions such as edema. It is a diuretic, which helps decrease the amount of water in the body by increasing the flow of urine.

Is there any reason not to take this drug?

You should not use this drug if you are allergic to it or to other similar drugs called thiazides (e.g., chlorthalidone, indapamide, metolazone). Tell your doctor if you have or have ever had:

  • difficulty going to the bathroom (e.g. urinary incontinence)
  • gout
  • high blood sugar or diabetes
  • low blood pressure (e.g. hypotension)
  • pancreatitis
  • problems with your cholesterol or triglycerides
  • problems with your kidney or liver
  • systemic lupus erythematosus
  • high or low levels of sodium, potassium, magnesium or calcium in your blood
  • allergic reactions to sulfites or yellow-dye (tartrazine-FD&C yellow #5) – may be present in some thiazide products; ask your pharmacist to check the ingredients of your product
  • an allergic reaction to sulfa-like drugs (e.g. Septra, sulfamethoxazole) – you may have an increased risk to an allergic reaction but overall, your risk is likely minimal

What about possible side effects?

The most common side effects are:

  • low levels of sodium, potassium or magnesium - your doctor may perform blood tests to check on these while you are taking the drug
  • high levels of uric acid or calcium
  • going to the bathroom more often
  • dizziness, lightheadedness
  • low blood pressure
  • muscle cramps

These side effects are usually related to dose, the use of other medications and other factors (e.g. older age, other medical conditions). Some of these side effects may go away with time. Talk to your doctor or pharmacist about whether you have any risk factors that may make you more sensitive to these side effects. Contact your doctor if these symptoms continue or become worse.

Other side effects include:

  • increased sensitivity to the sun
  • rash
  • high blood sugar and higher cholesterol levels (this usually does not happen at the doses that are being used by your doctor (≤ 25mg)

This is not a complete list of side effects. If you are concerned about these or other unusual symptoms while taking this medication, ask your doctor and/or pharmacist for more information and advice.

What if I am taking other drugs?

Always provide your doctor with a list of all other drugs you are taking (including over-the-counter medications and herbal/natural products) as they may interact and may change the safety or effectiveness of either drug. Tell your doctor specifically if you are taking any of these drugs as these are the most common interactions and he/she may need to make changes or monitor you more closely.

  • candesartan, valsartan, irbesartan, eprosartan, losartan, vandesartan, telmisartan
  • cholestyramine
  • digoxin
  • ACE-inhibitors (e.g. enalapril, lisinopril, ramipril)
  • lithium
  • other medications to treat high blood pressure - may increase your chance of experiencing low blood pressure
  • ASA & other anti-inflammatories (e.g. ibuprofen, voltaren, diclofenac) (e.g. ibuprofen, naproxen, voltaren) – may influence how well hydrochlorothiazide can work

If you are taking this drug to treat high blood pressure, be careful of certain over-the-counter medicines that may increase your blood pressure. These include some cough and cold medicines. Ask your doctor or pharmacist for more information.

This is not a complete list of drug interactions. Ask your doctor or pharmacist to review your list of medications.

Other information:

Diabetes: There is a small chance that your blood sugar levels could rise. Test it more often to be sure.

Sun Protection: Your skin may burn more easily while taking this medication – it is recommended that you use sunscreen and wear protective clothing to decrease the chance of this happening.

Children: Can be used safely in children.

Seniors: Are usually more sensitive to the effects of this medication. Lower doses should be used in the beginning and you should be monitored more closely for side effects (e.g. blood levels of sodium, potassium, dizziness, incontinence, low blood pressure).

Pregnant women: In general, not considered a first-line drug. It has been used in pregnancy but only in specific circumstances. Talk to your doctor. In general, these drugs are not useful for normal swelling of feet and hands that occurs during pregnancy.

Women who are nursing: Compatible with breastfeeding but may decrease milk production. Talk to your doctor.

People who drive or operate machinery: Should not do so until they know the impact this drug has on them personally; may cause dizziness.

Alcohol: This medication can increase the likelihood of dehydration and thus may worsen the after effects of too much alcohol. If you drink always drink in moderation.

Overdose: If you experience any unusual reactions or if you seriously exceed the recommended dosage, call your doctor or 911.

Stopping the drug: Talk to your doctor before you stop taking this drug. Stopping the drug will likely cause your blood pressure to increase or your other symptoms (e.g. swollen ankles) to return.

If you miss a dose: Take it when you remember. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double dose.

Storage conditions: Closed container; cool, dry location away from excess moisture (not in the bathroom) and light; always out of reach of children.

Dietary precautions: This medicine may reduce potassium in your system. To help prevent this, your doctor may suggest that you eat more bananas and other potassium-rich foods or take a supplement. Do not take a supplement without first discussing it with your doctor.