Indapamide is a thiazide-related diuretic, which works by blocking sodium from being reabsorbed from your urine and into your blood, causing more sodium and water to be secreted from your body. It also helps the muscles around the blood vessels throughout your body to relax, allowing the blood to pass through more easily and lowering the pressure of the blood, making it useful in the treatment of hypertension.
Brand Names and Doses
Indapamide is generic name, which is the active drug found in the medication. There are also several brand names that you might recognise more easily:
- Natrilix (1.5 mg and 2.5 mg doses)
- Dapa-Tabs (2.5 mg dose)
- Insig (2.5 mg dose)
Each of these brands contain the same active drug and work in the same way; they are just produced by different companies and have brand names to distinguish them.
What type of drug is it?
Indapamide is a type of drug called a thiazide diuretic. Other medicines that are in the same class and work in a similar way are:
Other diuretics that have a slightly different mechanism of action are:
How does it work?
Indapamide changes the way your kidneys filter the blood to produce urine, leading to more fluid being excreted. It also has an effect on your blood vessels to lower blood pressure.
The nephrons in the kidneys are usually responsible for making urine and excreting waste products from your body. They constantly filter your blood, recognising the “good” nutrients that your body needs to reabsorb back into your blood from the “unwanted” products that come out in your urine.
When you take indapamide, the reabsorption of sodium and chloride in the nephrons is blocked, so that more of these salts are excreted in your urine than usual. This also causes more water to be secreted because the water “follows” where the sodium is in the body to maintain the right balance. It also has an effect on the potassium and magnesium salts in the body.
Indapamide can also have an effect on the muscles that surround your blood vessels, causing them to relax. This means that the blood vessels have room to expand and allow more blood to pass through, which decreases the blood pressure.
Indapamide has a range of effects on the body, and this can sometimes cause unwanted adverse effects. The most common and worrying effects are:
Low blood pressure (hypotension)
It is quite common for side effects to occur when indapamide is working too well and you end up with low blood pressure, which can make you feel dizzy or weak. This often occurs when you first start taking the medication and then gets better after a few days. If you find your blood pressure is still too low after a week, your should check with your doctor that the dose is right for you.
Indapamide works by stopping the sodium and chloride salts in the urine from being reabsorbed back into the bloodstream and body. As a result, the balance of salts in your body can change and sometimes this leads to problems. It’s not just sodium and chloride that are affected, but a range of different salts. You may experience:
- Low sodium levels (hyponatremia)
- Low potassium levels (hypokalemia)
- Low chlorine levels (hypochloremic alkalosis)
- Low magnesium levels (hypomagnesemia)
If you think you may be affected, you can ask your doctor for a blood test to make sure.
You may also notice a range of other effects, such as:
- Muscle cramps
- Frequent urination
- Abnormal glucose levels
For the complete list of side effects, you should see the medicine information leaflet inside your medication.
There are a couple of things you should be aware of before you start taking indapamide:
Gout – Indapamide can increase the risk of gout because it increases the concentration of uric acid in the bloodstream, which is involved in causing gout. If you are prone to gout, an alternative medication may be a better choice.
Renal Impairment – Indapamide is less effective and may cause harm if you have severe renal impairment, due to its effect on the kidneys and renal function.
When indapamide is used with other drugs that help to lower blood pressure and manage hypertension, they may cause blood pressure that is too low. There are also some other specific interactions:
ACE Inhibitors + Indapamide Interaction
In particular, ACE inhibitors and indapamide taken together is likely to cause low blood pressure, particularly for the first few doses. It is best to stop taking indapamide for a few days when beginning to take a new ACE inhibitor drug.
Lithium +Indapamide Interaction
Indapamide can decrease the amount of lithium that is excreted from the body and increase the risk of side effects. This combination is not recommended unless the concentration can be closely monitored.
Loop Diuretic +Indapamide Interaction
Taking a loop diuretic drug with indapamide can increase the risk of renal impairment and upset the balance of salts in the blood. tI should only be used in small doses.
NSAID + Indapamide Interaction
NSAIDs and indapamide should not be used together unless the blood pressure, renal function and weight is closely monitored and the dose adjusted according to the results.
Pregnancy and Breastfeeding
Indapamide should not be used by women who are pregnant or planning to become pregnant, as it may upset the balance of salts in the blood and cause harm to the baby.
It can be taken while breastfeeding, but only in low doses as small amounts of the drug is excreted in breast milk and may affect your baby. Although it is unlikely, it may also decrease milk production.