Midopril (Captopril)

Midopril (Captopril) Uses, Dosage, Side Effects, Food Interaction and all others data.

Midopril (Captopril) competitively inhibits the conversion of angiotensin I (ATI) to angiotensin II (ATII), thus resulting in reduced ATII levels and aldosterone secretion. It also increases plasma renin activity and bradykinin levels. Reduction of ATII leads to decreased Na and water retention. This promotes vasodilation and BP reduction.

Midopril (Captopril), an ACE inhibitor, antagonizes the effect of the RAAS. The RAAS is a homeostatic mechanism for regulating hemodynamics, water and electrolyte balance. During sympathetic stimulation or when renal blood pressure or blood flow is reduced, renin is released from the granular cells of the juxtaglomerular apparatus in the kidneys. In the blood stream, renin cleaves circulating angiotensinogen to ATI, which is subsequently cleaved to ATII by ACE. ATII increases blood pressure using a number of mechanisms. First, it stimulates the secretion of aldosterone from the adrenal cortex. Aldosterone travels to the distal convoluted tubule (DCT) and collecting tubule of nephrons where it increases sodium and water reabsorption by increasing the number of sodium channels and sodium-potassium ATPases on cell membranes. Second, ATII stimulates the secretion of vasopressin (also known as antidiuretic hormone or ADH) from the posterior pituitary gland. ADH stimulates further water reabsorption from the kidneys via insertion of aquaporin-2 channels on the apical surface of cells of the DCT and collecting tubules. Third, ATII increases blood pressure through direct arterial vasoconstriction. Stimulation of the Type 1 ATII receptor on vascular smooth muscle cells leads to a cascade of events resulting in myocyte contraction and vasoconstriction. In addition to these major effects, ATII induces the thirst response via stimulation of hypothalamic neurons. ACE inhibitors inhibit the rapid conversion of ATI to ATII and antagonize RAAS-induced increases in blood pressure. ACE (also known as kininase II) is also involved in the enzymatic deactivation of bradykinin, a vasodilator. Inhibiting the deactivation of bradykinin increases bradykinin levels and may sustain its effects by causing increased vasodilation and decreased blood pressure.

Trade Name Midopril (Captopril)
Availability Prescription only
Generic Captopril
Captopril Other Names Captopril, Captoprilum, Captopryl, L-Captopril
Related Drugs amlodipine, lisinopril, metoprolol, losartan, furosemide, carvedilol, hydrochlorothiazide, spironolactone, hydralazine, nifedipine
Type
Formula C9H15NO3S
Weight Average: 217.285
Monoisotopic: 217.077264041
Protein binding

25-30% bound to plasma proteins, primarily albumin

Groups Approved
Therapeutic Class Angiotensin-converting enzyme (ACE) inhibitors
Manufacturer
Available Country Tunisia
Last Updated: September 19, 2023 at 7:00 am
Midopril (Captopril)
Midopril (Captopril)

Uses

Hypertension: Mild to moderate hypertension as an adjunct to thiazide therapy in patients who have not responded effectively to thiazide treatment alone.

Severe hypertension: Where standard therapy has failed. Cardopril is effective alone or in combination with other antihypertensive agents especially thiazide type of diuretics. The blood pressure lowering effect of Cardopril and thiazides are approximately additive.

Congestive heart failure: It is also used as an adjunct to the treatment of severe congestive heart failure.

Midopril (Captopril) is also used to associated treatment for these conditions: Aldosteronism, Anatomic renal artery stenosis, Congestive Heart Failure (CHF), Diabetic Nephropathy, Heart Failure, High Blood Pressure (Hypertension), Hypertensive crisis, Non ST Segment Elevation Acute Coronary Syndrome, Raynaud's Phenomenon, Ejection fraction of 40% or less Left ventricular dysfunction

How Midopril (Captopril) works

There are two isoforms of ACE: the somatic isoform, which exists as a glycoprotein comprised of a single polypeptide chain of 1277; and the testicular isoform, which has a lower molecular mass and is thought to play a role in sperm maturation and binding of sperm to the oviduct epithelium. Somatic ACE has two functionally active domains, N and C, which arise from tandem gene duplication. Although the two domains have high sequence similarity, they play distinct physiological roles. The C-domain is predominantly involved in blood pressure regulation while the N-domain plays a role in hematopoietic stem cell differentiation and proliferation. ACE inhibitors bind to and inhibit the activity of both domains, but have much greater affinity for and inhibitory activity against the C-domain. Midopril (Captopril), one of the few ACE inhibitors that is not a prodrug, competes with ATI for binding to ACE and inhibits and enzymatic proteolysis of ATI to ATII. Decreasing ATII levels in the body decreases blood pressure by inhibiting the pressor effects of ATII as described in the Pharmacology section above. Midopril (Captopril) also causes an increase in plasma renin activity likely due to a loss of feedback inhibition mediated by ATII on the release of renin and/or stimulation of reflex mechanisms via baroreceptors. Midopril (Captopril)’s affinity for ACE is approximately 30,000 times greater than that of ATI.

Dosage

Midopril (Captopril) dosage

Diabetic nephropathy:

  • Adult: Type 1 diabetics: 75-100 mg/day in divided doses.

Post-myocardial infarction:

  • Adult: May be started 3-16 days after MI. Initially, 6.25 mg/day followed by 12.5 mg tid for 2 days, then 25 mg tid. Maintenance: 75-150 mg/day in 2 or 3 divided doses.

Hypertension:

  • Adult: Initially, 12.5 mg bid, 1st dose preferably at bedtime to avoid precipitous fall in BP, gradually increased at 2-4-wk intervals according to response. Maintenance: 25-50 mg bid. Max: 50 mg tid. Patients on diuretics: 6.25 mg bid.
  • Child: Neonates and infants: 0.15 mg/kg. Max: 6 mg/kg in 2 or 3 divided doses according to response. Childn and adolescents: 0.3 mg/kg. Max: 6 mg/kg in 2 or 3 divided doses according to response.
  • Elderly: Initially, 6.25 mg bid.

Heart failure:

  • Adult: Initially, 6.25-12.5 mg bid or tid. Maintenance: 25 mg bid or tid. Max: 50 mg tid.
  • Child: Initially, 0.25 mg/kg/day, increased up to 2.5 or 3.5 mg/kg/day in 3 divided doses.

Side Effects

Neutropenia, anaemia and thrombocytopenia; proteinuria, elevated blood urea and creatinine, elevated serum potassium and acidosis; hypotension, tachycardia; rashes usually pruritic, may occur; Reversible and usually self limiting taste impairment has been reported. Stomatitis resembling aphthous ulcers has also been reported.

Toxicity

Symptoms of overdose include emesis and decreased blood pressure. Side effects include dose-dependent rash (usually maculopapular), taste alterations, hypotension, gastric irritation, cough, and angioedema.

Precaution

Patients with bilateral renal artery stenosis, collagen vascular disease, aortic or mitral valve stenosis, volume and/or Na depletion. Renal impairment. Lactation.

Interaction

Concurrent treatment with NSAIDs reduces hypotensive action and increases the risk of nephrotoxicity. Additive hyperkalaemic effect with K supplements, K-sparing diuretics, and other drugs (e.g. heparin). May increase risk of leucopenia with procainamide, allopurinol, cytostatic or immunosuppressants. May increase risk of lithium toxicity. Increased risk of nitritoid reactions with gold (Na aurothiomalate).

Food Interaction

  • Avoid hypertensive herbs (e.g. bayberry, blue cohosh, cayenne, ephedra, and licorice).
  • Avoid potassium-containing products. Potassium products increase the risk of hyperkalemia.
  • Limit salt intake. Salt may attenuate the antihypertensive effect.
  • Take separate from meals. The presence of food decreases absorption. Take one hour prior to meals.

[Moderate] GENERALLY AVOID: Moderate-to-high dietary intake of potassium can cause hyperkalemia in some patients who are using angiotensin converting enzyme (ACE) inhibitors.

In some cases, affected patients were using a potassium-rich salt substitute.

ACE inhibitors can promote hyperkalemia through inhibition of the renin-aldosterone-angiotensin (RAA) system.



MANAGEMENT: It is recommended that patients who are taking ACE inhibitors be advised to avoid moderately high or high potassium dietary intake.

Particular attention should be paid to the potassium content of salt substitutes.

Elimination Route

60-75% in fasting individuals; food decreases absorption by 25-40% (some evidence indicates that this is not clinically significant)

Half Life

2 hours

Pregnancy & Breastfeeding use

Pregnancy Category D. There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk

Contraindication

Angioedema related to previous ACE inhibitor treatment, hereditary or idiopathic angioneurotic oedema. Concomitant use with aliskiren in diabetic patients. Pregnancy.

Acute Overdose

Symptoms: Severe hypotension, shock, stupor, bradycardia, electrolyte disturbances and renal failure.

Management: Perform gastric lavage, administer adsorbent and sodium sulfate with in 30 min of ingestion; NaCl 0.9% IV infusion. Treatment with angiotensin-II may also be considered. Administer atropine in case of extensive vagal reactions or bradycardia. Pacemaker is also an option. Elimination may be enhanced by haemodialysis.

Storage Condition

Store below 30° C

Innovators Monograph

You find simplified version here Midopril (Captopril)

Midopril (Captopril) contains Captopril see full prescribing information from innovator Midopril (Captopril) Monograph, Midopril (Captopril) MSDS, Midopril (Captopril) FDA label

FAQ

What is Midopril (Captopril) is used for?

Midopril (Captopril) is an angiotensin-converting enzyme inhibitor used for the treatment of hypertension and some types of congestive heart failure.

How safe is Midopril (Captopril)?

It is concluded that Midopril (Captopril) is safe and effective in the long-term treatment of hypertension, however, majority of the patients with severe forms of hypertension required double or multiple combinations.

How does Midopril (Captopril) work?

Midopril (Captopril) works by opening your blood vessels. 

What are the common side effects of Midopril (Captopril)?

Common side effects of Midopril (Captopril) are include:

  • dizziness or lightheadedness.
  • salty or metallic taste, or decreased ability to taste.
  • cough.
  • fast heartbeat.
  • excessive tiredness.

Is Midopril (Captopril) safe during pregnancy?

This Midopril (Captopril) should not be used during pregnancy unless there are no alternatives and the benefit outweighs the risk to the fetus.

Is Midopril (Captopril) safe during breastfeeding?

Midopril (Captopril) use in breastfeeding is not recommended in the first few weeks after delivery because of the possibility of profound neonatal hypotension.

Can I drink alcohol with Midopril (Captopril)?

Drinking alcohol can further lower your blood pressure and may increase certain side effects of Midopril (Captopril). 

Can I drive after taking Midopril (Captopril)?

Do not drive or operate heavy machinery until you know how this medication affects you.

When should be taken of Midopril (Captopril)?

Midopril (Captopril) is usually taken two or three times a day on an empty stomach, 1 hour before a meal. To help you remember to take captopril, take it around the same time(s) every day.

How many time can I take Midopril (Captopril) daily?

Adults, At first  25 milligrams (mg) two or three times a day.

Can I take Midopril (Captopril) on an empty stomach?

Midopril (Captopril) take on an empty stomach, 1 hour before a meal.

How long does Midopril (Captopril) take to work?

In most patients, the antihypertensive effect began about 15 to 30 minutes after oral administration of Midopril (Captopril) ; the peak effect was achieved after 60 to 90 minutes.

How long does Midopril (Captopril) stay in my system?

The apparent elimination half-life of unchanged Midopril (Captopril) in blood is about 2 hours. Greater than 95% of the absorbed dose is eliminated in the urine within 24 hours; 40-50% is unchanged drug and the remainder are inactive disulphide metabolites (captopril disulphide and captopril cysteine disulphide).

Can I take Midopril (Captopril) for a long time?

Midopril (Captopril) oral tablet is used for long-term treatment. It comes with serious risks if you don't take it as prescribed.

Is Midopril (Captopril) good for kidneys?

Midopril (Captopril) and other ACE inhibitors also may cause kidney failure and increased levels of potassium in the blood. Serious but, fortunately, very rare side effects are liver failure and angioedema (swelling of lips and throat that can obstruct breathing).

Who should not take Midopril (Captopril)?

You should not use this Midopril (Captopril) if you are allergic to Midopril (Captopril).
To make sure Midopril (Captopril) is safe for you, tell your doctor if you have:

  • kidney disease (or if you are on dialysis);
  • liver disease;
  • diabetes;
  • a connective tissue disease such as Marfan syndrome, Sjogren's syndrome, lupus, scleroderma, or rheumatoid arthritis; or
  • if you have had an organ transplant.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I take too much Midopril (Captopril)?

If you take too much: If you take too much bran, you'll have a significant drop in blood pressure. If you think you've taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

What happen If I stop taking Midopril (Captopril)?

If you stop taking it suddenly: You shouldn't stop taking Midopril (Captopril) without talking to your doctor. Stopping the drug suddenly can cause your blood pressure to get higher. This may increase your risk of a heart attack or stroke.

Is Midopril (Captopril) hard on kidneys?

The possible protective action of captopril on hypertensive renal damage is poorly understood.

Does Midopril (Captopril) affect the liver?

Most instances of acute liver injury reported with captopril use have been self limited, but there have been rare reports of acute liver failure due to captopril and several reports of cholestatic hepatitis leading to prolonged jaundice.

*** Taking medicines without doctor's advice can cause long-term problems.
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