Captopril
Benjamin Clanner-Engelshofen is a freelance writer in the medical department. He studied biochemistry and pharmacy in Munich and Cambridge / Boston (USA) and noticed early on that he particularly enjoyed the interface between medicine and science. That is why he went on to study human medicine.
More about the experts All content is checked by medical journalists.The active ingredient captopril is a blood pressure lowering drug from the class of ACE inhibitors. As the first ACE inhibitor to be developed, it has been researched the longest, but it also has side effects that do not occur with newer drugs in this class. Here you can read everything you need to know about captopril: effect and use, side effects and interactions.
This is how captopril works
The blood pressure in the human body is subject to a strictly and carefully controlled control circuit. This adapts the blood pressure to the respective requirements, for example when changing position (e.g. when getting up from lying down) as well as during exertion such as endurance sports.
The blood pressure is mainly controlled by a hormonal system, the so-called RAAS (Renin-Angiotensin-Aldosterone System). Here, a protein (angiotensinogen) is formed in the liver, which is converted into the blood pressure-increasing hormone angiotensin II in two stages: First, the compound angiotensin I is formed with the help of the enzyme renin. This is then converted into angiotensin II by the enzyme ACE (angiotensin converting enzyme) converted. The enzyme renin is formed in the kidneys and released into the blood. The enzyme ACE sits firmly on the superficial cells of the kidneys and lungs. Since the kidneys and lungs have extremely fine blood vessels, these organs are particularly dependent on stable blood pressure in order not to be damaged - too high a pressure will quickly burst the fine vessels.
Angiotensin II causes the blood vessels to constrict, less salt and water are excreted through the kidneys and triggers a feeling of thirst and a thirst for salt. All of the effects raise blood pressure.
Especially in old age, the control of this boom pressure system (RAAS) can derail, which means that the blood pressure is permanently too high. From a blood pressure of 140/90 millimeters of mercury (mmHg) one speaks of high blood pressure. If the blood pressure is permanently above these values, this can damage the cardiovascular system and internal organs in the long term.
The antihypertensive drug captopril blocks the ACE enzyme as an ACE inhibitor. This results in less angiotensin II - the blood pressure drops.
Uptake, breakdown and excretion of captopril
After ingestion as a tablet, the active ingredient dissolves in the gastric juice and enters the blood via the intestines. The highest blood levels are reached after about an hour. In the blood, captopril reaches the enzyme ACE in the lungs and kidneys and inhibits it. Half of the active ingredient is excreted unchanged and half as an inactive metabolic product via the kidneys with the urine. Two hours after ingestion, the blood level has dropped by about half again.
When is captopril used?
The active ingredient captopril is approved for the treatment of:
- from high blood pressure
- after a heart attack
Captopril must be taken continuously to keep blood pressure in the normal range.
This is how captopril is used
The blood pressure lowering drug captopril is taken as a tablet before, with or after a meal with a glass of water. It usually starts with a daily dose of 25 milligrams of captopril divided into two doses a day (morning and evening). Then the dose is slowly increased, as prescribed by the doctor, until the blood pressure is stable in the normal range. The maximum daily dose should no longer be 150 milligrams of captopril.
If captopril alone cannot lower blood pressure sufficiently, a second blood pressure lowering drug is usually also prescribed, often hydrochlorothiazide (HCT). There are also tablets that contain both active ingredients so that patients do not have to take two different preparations. In combination with another active ingredient, captopril may only have to be taken once a day.
What are the side effects of captopril?
Most captopril side effects occur particularly at the beginning of treatment and subside as the treatment progresses, which is why therapy should not be stopped too quickly.
One to ten percent of those treated report adverse effects such as sleep disorders, taste disorders, dizziness, shortness of breath, dry cough, nausea, vomiting, stomach pain, diarrhea, constipation, dry mouth, itching, rash and hair loss. Patients should tell their doctor about any side effects, as it may be necessary to change therapy (such as a dry cough).
Occasionally, captopril also causes palpitations, tight hearts, palpitations, an excessive decrease in blood pressure, flushing of the face, paleness, chest pain, exhaustion and malaise.
What should be considered when taking captopril?
Captopril can interact with other drugs, especially those that affect blood pressure. Therefore, the simultaneous treatment of captopril and other blood pressure medications (including dehydrating agents = diuretics) should be started with low doses and should be closely monitored by the doctor.
The use of drugs against depression, psychoses and delusions (antipsychotics / neuroleptics) can increase the blood pressure lowering effect of captopril.
Captopril can increase blood levels of the mood stabilizer lithium, which can cause undesirable side effects.
The gout drug allopurinol, anti-cancer drugs and agents that suppress the immune system (immunosuppressants) can reduce the number of white blood cells when used at the same time as captopril.
Painkillers from the group of non-steroidal anti-inflammatory drugs (NSAIDs) such as acetylsalicylic acid (ASA), ibuprofen, diclofenac and naproxen can worsen blood flow to the kidneys and promote electrolyte changes in the blood. They should therefore only be taken with caution together with the antihypertensive agent.
Captopril increases the blood sugar lowering effect of oral antidiabetic drugs and insulin. As a result, diabetics can suffer from hypoglycaemia more quickly.
The antihypertensive drug should not be taken during pregnancy because there is little data on this.
Children and adolescents as well as the elderly and patients with impaired renal function can be treated with captopril in a correspondingly reduced dose.
How to get Captopril medication
Preparations with the active ingredient captopril require a prescription in Germany.
How long has captopril been known?
The active ingredient captopril was developed in 1974 by the pharmaceutical company Squibb (now Bristol-Myers Squibb) using a natural substance from the venom of the Jararaca lance viper. It was patented in 1976. It was approved in Europe in 1980 and in the USA in 1981. Since the mid-1990s, there have been several generic drugs containing the active ingredient captopril on the German drug market.
Tags: hospital prevention Diseases
