The effect of diuretics on high blood pressure is gradual, taking up to 6 weeks for a full effect. If you are taking a diuretic for congestive heart failure or other condition with swelling, you probably will notice that you will need to urinate more often. If this becomes a problem at night, let your healthcare provider know. To help your diuretic be more effective, cut down on the amount of salt in your diet. Ask your provider or dietitian for specific ideas on how to reduce the amount of sodium in your diet.
Diuretics given alone or with other medications can cause side effects.
The most common side effect is low blood pressure caused by the loss of too much fluid. This is more common in people over the age of 65 and with people taking other medications that can lower blood pressure. An early sign of losing too much fluid is becoming dizzy or lightheaded when standing up. Always get up slowly, especially at night or first thing in the morning. If you do feel dizzy, lie back down and call your healthcare provider.