Indapen – composition, action and application, side effects, interactions

Proven content

Indapen is a medicine used to lower blood pressure. Indapen also has a diuretic effect. Read what the Indapen leaflet contains information, what is its composition and how to take it.

Indapen – active substances

Indapen is a medicine whose active substance is indapamide, which is a diuretic. Most diuretics increase the amount of urine produced by the kidneys. However, indapamide is different from other diuretics as it only causes a slight increase in the amount of urine produced. Indapen is used to treat high blood pressure (essential hypertension).

As already mentioned, the active ingredient in Indapen is indapamide. The auxiliary substances are:

1. microcrystalline cellulose,
2. crospovidone
3. magnesium stearate,
4. sheath:
5. hypromeloza,
6. stearic acid,
7. microcrystalline cellulose,
8. titanium dioxide (E 171).

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Indapen – mechanism of action

Indapamide is a non-thiazide sulfonamide containing an indole ring. It is used as a diuretic. At a dose of 2,5 mg a day, indapamide lowers blood pressure in people with hypertension. At a dose of 2,5 mg indapamide per day, the antihypertensive effect is maximal and the diuretic effect is subclinical.

The mechanism of action (vascular) of indapamide includes:

1. reduction of vascular smooth muscle contractility by influencing the transport (mainly calcium),
2.  vasodilation due to the stimulation of the synthesis of prostaglandin PGE2 and dilating prostaglandin
3. vascular and platelet aggregation inhibiting prostacyclin PGI2,
4. potentiation of the vasodilating effect of bradykinin.

In the short, medium and long-term treatment of people with hypertension, indapamide has been shown to:

1. reduces left ventricular hypertrophy,
2. does not adversely affect the metabolism of lipids: triglycerides, LDL cholesterol and HDL cholesterol,
3. it does not adversely affect glucose metabolism, even in diabetic hypertensive patients. 

Indapamide is rapidly and completely absorbed from the gastrointestinal tract. After oral administration, the maximum concentration in the blood is reached after 1-2 hours. Food does not affect the amount absorbed.

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Indapen – dosage

The recommended dosage of Indapen is as follows – 1 tablet (2,5 mg) per day, preferably in the morning. The effect of Indapen is gradual and the maximum reduction in blood pressure may not be reached until several months after starting treatment.

Doses higher than 2,5 mg of Indapen per day are not recommendedit will not lower your blood pressure any further, but the diuretic effect may be increased. If the use of Indapen 1 tablet a day does not lower your blood pressure sufficiently, your doctor may change your blood pressure to other medicines.

Indapen can be used with beta blockers, ACE inhibitors, methyldopa, clonidine and other adrenergic blockers. The use of Indapen with diuretics that may cause hypokalaemia is not recommended.

Age, body weight and gender should be taken into account when assessing plasma creatinine levels in elderly patients. Elderly patients can be treated with Indapen when renal function is normal or only minimally impaired.

Indapen – warnings and precautions

The use of Indapen, which acts in a similar way to thiazides, may cause the development of hepatic encephalopathy, especially in the case of electrolyte imbalances. The use of diuretics should be discontinued immediately if symptoms of hepatic encephalopathy occur. The use of Indapen in people with impaired kidney function is also not recommended.

To date, cases of photosensitivity reaction associated with the use of thiazide diuretics and other drugs with a similar effect, including Indapen, have been reported. If a photosensitivity reaction occurs during treatment with Indapen, it is recommended that the treatment be withdrawn. If re-treatment with the diuretic becomes necessary, it is recommended to protect the skin area exposed to sunlight or to artificial UVA radiation.

When using Indapen in people with diabetes, especially in those with concomitant hypokalaemia, blood glucose levels should be monitored. And in people with hyperuricemia, there is a tendency to increase the frequency of gout attacks.

The use of Indapen may cause positive results in doping tests in athletes.

So, you should take special care with Indapen if you have:

1. liver failure
2. kidney failure
3. diabetes,
4. gout
5. water and electrolyte imbalance,
6. sensitivity to light,
7. if you are at increased risk of hypokalaemia (low blood levels of potassium with symptoms such as muscle weakness, tremors or abnormal heart rhythms),
8. if the patient has an increased risk of hypercalcemia (excessive levels of calcium in the blood serum, manifested, among others, by lack of appetite, nausea, vomiting or heart failure),
9. if you are to undergo an examination to assess the function of the parathyroid glands.

Moreover, one of the main contraindications to the use of Indapen is hypersensitivity to the active substance or excipients.

During treatment with Indapen, especially at the beginning of treatment or when adding another antihypertensive agent, you may experience symptoms related to a fall in blood pressure. Under these circumstances, the ability to drive and use machines may be impaired.

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Indapen – interactions with other drugs

Drugs that should not be used concomitantly with Indapenem include lithium. There may be an increase in the combination of the two drugs plasma lithium levels with symptoms of overdose, such as in a sodium diet (reduced urinary lithium excretion). If concomitant use of a diuretic is required, monitoring of plasma lithium levels and dose adjustment are required.

Drugs that should be used with caution with indapamide include:

1. Medicines that affect heart rhythm that cause torsades de pointes – polymorphic ventricular tachycardia:
2. group Ia antiarrhythmics (quinidine, hydroquinidine, disopyramide),
3. group III antiarrhythmics (amiodarone, sotalol, dofetilide, ibutilide),
4. some antipsychotics: phenothiazine derivatives (chlorpromazine, cyamemazine, levomepromazine, thioridazine, trifluoperazine), benzamide derivatives (amisulpiride, sulpiride, sultopride, thiapride), butyrophenone derivatives (droperidol, haloperidol),
5. other drugs: bepridil, cisapride, diphemanil, intravenous erythromycin, halofantrine, mizolastine, pentamidine, sparfloxacin, moxifloxacin, intravenous vincamine,
6. non-steroidal anti-inflammatory drugs (administered systemically), including selective COX-2 inhibitors, high doses of salicylates (≥3 g / day) – the possibility of reducing the antihypertensive effect of indapamide,
7. angiotensin-converting enzyme (ACE) inhibitors – starting ACE inhibitors in people with sodium depletion (especially in the case of renal artery stenosis) carries the risk of sudden hypotension and the risk of acute renal failure. In high blood pressure, diuretic treatment may cause sodium depletion,
8. other drugs inducing hypokalaemia – intravenous amphotericin B, glucocorticosteroids and mineralocorticosteroids (systemic administration), tetracosactide, stimulant laxatives – increased risk of hypokalaemia,
9. baclofen – increases the antihypertensive effect of indapamide,
10. digitalis glycosides – hypokalemia is a predisposing factor to the development of toxic symptoms after the use of digitalis glycosides, therefore it is necessary to monitor potassium levels, perform an ECG and, if necessary, modify the treatment.

Drugs for which concomitant use with Indapenem may be considered:

1. potassium-sparing diuretics (amiloride, spironolactone, triamterene) – rational combination of these drugs, beneficial for some patients, does not eliminate the risk of hypokalemia (especially in people with diabetes or renal failure) or hyperkalemia,
2. metformin – increased risk of metformin induced lactic acidosis due to possible functional renal failure due to the use of diuretics, especially loop diuretics, 
3. iodine-containing contrast agents – in case of dehydration caused by diuretics, there is an increased risk of developing acute renal failure, especially if high doses of iodine-based contrast agent have been used.
4. tricyclic antidepressants, neuroleptics – increased hypotensive effect and an increased risk of orthostatic hypotension,
5. calcium (calcium salts) – risk of hypercalcaemia as a result of reduced kidney calcium excretion,
6. ciclosporin, tacrolimus – risk of increased plasma creatinine levels, without changing ciclosporin levels, even in the absence of water and / or sodium loss,
7. corticosteroids, tetracosactide (given systemically) – reduced hypotensive effects (sodium and water retention due to the action of corticosteroids).

Indapen – pregnancy and breastfeeding

The use of diuretics should be strictly avoided during pregnancy. They should never be used to treat physiological swelling that occurs during pregnancy. Diuretics can cause foetoplacental ischemia with a risk of impaired growth of the fetus.

Indapamide is also excreted in human milk. Therefore, the use of Indapen while breast-feeding is not recommended.

See: Mother’s milk from a pediatrician’s perspective – truths and myths

Indapen – side effects

The use of Indapen may cause certain side effects. In the package leaflet they are characterized as common, uncommon, very rare, frequency unknown.

Common side effects with Indapen: (affects 1 to 10 in 100 people):

1. low level of potassium in the blood which can cause muscle weakness
2. maculopapular rashes (especially in people prone to allergic reactions or those suffering from bronchial asthma).

Uncommon side effects with Indapen (affects 1 to 10 in 1000 people):

1. vomiting,
2. purpura (a disease with symptoms of skin rash, abdominal pain and joint pain).

Rare side effects with Indapen (affects 1 to 10 users in 10):

1. tiredness, dizziness, headache, tingling (paraesthesia)
2. nausea, constipation, dry mouth.

Very rare side effects with Indapen (affects less than 1 in 10 people):

1. thrombocytopenia (a decrease in the number of platelets in the blood, which increases the risk of bleeding and bruising), leukopenia (a decrease in the total number of white blood cells in the blood), agranulocytosis (complete or almost complete loss of granulocytes (a type of white blood cell) in the blood), aplastic anemia (decrease in the number of blood cells) due to the lack or incomplete formation of the bone marrow), haemolytic anemia (reduction in the number of red blood cells),
2. heart rhythm disturbances, low blood pressure,
3. inflammation of the pancreas, kidney failure, liver problems
4. angioedema (swelling of the face, lips, tongue and / or throat that may make it difficult to swallow or breathe) and / or urticaria, toxic epidermal necrolysis (erythematous blistering lesions of the skin and mucous membranes leading to creeping large areas epidermis and exposing large areas of the skin), Stevens-Johnson syndrome (blisters turning into erosions, on the mucous membranes of the mouth, conjunctiva, genitals),
5. hypercalcemia.

Not known side effects with Indapen (frequency cannot be estimated from the available data):

1. swoon,
2. severe abnormal heart rhythm (torsade de pointes),
3. in people with liver failure, the possibility of developing hepatic encephalopathy (a disease that damages the brain), hepatitis,
4. increased liver enzymes
5. the possibility of exacerbation of the symptoms of coexisting systemic lupus erythematosus,
6. allergic reactions to light (change in the appearance of the skin) after exposure to sunlight or artificial UVA rays
7. abnormal heart ECG,
8. hypokalemia (low potassium levels) – especially dangerous in patients who are at the greatest risk of developing hypokalemia, due to the risk of arrhythmias and the increased toxicity of digitalis preparations,
9. hyponatraemia (low blood sodium levels) with hypovolaemia (decreased blood volume) causing dehydration (increased risk of dehydration in elderly patients and patients with heart failure) and orthostatic (associated with repositioning e.g. from sitting to standing) pressure drops blood pressure. The concomitant loss of chloride ions may lead to a slightly increased, secondary, controlled metabolic alkalosis,
10. increased levels of uric acid and blood glucose. In patients with diabetes or gout, the physician should consider the use of diuretics.

Indapen – overdose

Overall, no toxic effects were found for indapamide up to 40 mg, which is approximately 16 times the therapeutic dose. ABOUTsymptoms of acute poisoning result from water and electrolyte imbalance (hyponatremia, hypokalemia). Nausea, vomiting, hypotension, muscle spasms, dizziness, somnolence, confusion, polyuria, oliguria up to anuria (due to hypovolaemia) may occur. In the event of overdose, gastric lavage or activated charcoal should be administered as soon as possible, and the fluid and electrolyte balance should be restored in a hospital setting.