Yes, you may want to avoid some medicines while taking hydrochlorothiazide (HCTZ). Generally, lithium and HCTZ should NEVER be taken together. Taking HCTZ with lithium can cause dangerous levels of lithium in the body.
Other medicines and substances to avoid, if you can, are:
Alcohol, Barbiturates, or Narcotics. Taking any of these with HCTZ can cause blood pressure to drop too much. Low blood pressure can cause dizziness. People should use caution when taking these with HCTZ. They should be careful changing positions or standing up.
Other High Blood Pressure Drugs. Taking HCTZ with other high blood pressure medicines can cause blood pressure to drop too much. Low blood pressure can cause dizziness. People should use caution when changing positions or standing up. However, taking more than one blood pressure drug is very common. Doctors often give more than one medicine to people with severe high blood pressure.
Corticosteroids and Adrenocorticotropic Hormone (ACTH). Taking corticosteroids or ACTH with HCTZ can lower blood potassium levels. This can be dangerous. The doctor will need to watch potassium levels and heart function. Some people will have to take potassium pills.
Cholestyramine and Colestipol Resins. Taking HCTZ with cholestyramine or colestipol resins may keep HCTZ from being absorbed in the gastrointestinal tract. This can cause a rise in blood pressure or water retention.
Nonsteroidal Anti-inflammatory Drugs (NSAIDs). Taking NSAIDS with HCTZ lessens the HCTZ effects. Blood pressure may not lower as much as expected.
Muscle Relaxants. Taking certain types of muscle relaxants with HCTZ may raise the relaxing effects too much. It can cause excessive sleepiness and muscle weakness.
If you must take one of these with HCTZ, you may need regular check-ups with your doctor.
This is not a complete list. Tell your doctor about all the medicines you take.
Stay safe – tell your doctor what you take!