Captopril Sublingual: Mechanism of Action, Indications, Dosage, Precautions, Side Effects, Contraindications and Interactions

It is a hypotensive drug, which can be used as a treatment for a hypertensive emergency is easy to apply, fast, effective and safe.

The treatment of sublingual captopril has been effective for the reduction of the systodiastolic figures and the stabilization of the patient.

Chemical formula

1 – [(2S) -3-mercapto-2-metilpropionil] -L- prolina

Mechanism of action

Captopril inhibits the enzyme that converts angiotensin, which achieves the transformation of angiotensin I into angiotensin II, which is a potent endogenous vasoconstrictor substance, resulting in a decrease in blood pressure through a double mechanism.

When arteriovenous vasodilatation occurs, it reduces the peripheral resistance and achieves the reabsorption of sodium and water, with the consequent decrease in blood volume, when the production of aldosterone decreases.

A special form of treatment in the case of hypertensive crisis, is the use of sublingual captopril, by this means, the drug dissolves in the saliva and reaches the circulatory system through the network of venous and lymphatic vessels.

As well as the conjunctive tissue present in the sublingual mucosa, achieving a high speed of absorption.


In a situation in which it produces a considerable elevation of blood pressure which must be controlled quickly to prevent damage to the target organs (heart, kidney, retina, brain and arteries), it is necessary to apply intrahospital treatment, with antihypertensive medications.

In these cases it is common to administer treatments sublingually, to achieve rapid absorption.

Captopril sublingual is indicated for the control of crisis in hypertension in situations of hypertensive emergencies.


The recommended dose for a hypertensive emergency is 25 mg with repetitions every 30 minutes as required, with monitoring of blood pressure.

With a maximum dose of 100 mg.

The use of this route for the administration of the medication must be done under medical supervision.

The first dose of 25 mg of sublingual captopril, guarantees a 25% reduction in blood pressure and the additional intake of 25 mg captopril ensures optimal control of blood pressure, only in extreme cases it is necessary to apply the third dose.


The use of captopril can cause conditions of facial, lingual and laryngeal angioedema, which could endanger the respiratory capacity. If this happens it is necessary to put into practice the measures to prevent suffocation.

Special emphasis must be placed on the formulation of the correct dose, the administration of other antihypertensive drugs, in order to avoid hypotensive crises.

It is convenient to carry out constant monitoring of blood pressure levels.

Special attention should be paid to certain categories of patients at risk, such as immunosuppressed patients or patients with functional renal-type disabilities, among others.

Side effects

Side effects of sublingual captopril are quite frequent, but are not clinically relevant, may occur as episodes of itchy rash, fever, dry cough, photosensitivity, headache, chest pain, dizziness, redness or paleness, metallic taste between others.


The use of sublingual captopril is not recommended in case of hypersensitivity to any of its components, with aortic stenosis and severe impairment of kidney function. It is also contraindicated in pregnancy and lactation.

Drug Interactions

Captopril can develop interactions with the following medications:

  • Potassium supplements or diuretics, which causes an increase in plasma levels of this element.
  • Hypoglycaemic drugs, an increase in the glucose-lowering effect.
  • Corticosteroids with an increase in water retention.
  • Negatively charged membranes, such as hemodialysis, with an increase in anaphylactic episodes.
  • Lithium salts, resulting in accumulation and increase cytotoxic effects.

Captopril sublingual vs embarazo

The benefits of sublingual captopril in the management of hypertensive crises, presents an alternative for the use of sublingual captopril, as an alternative to the medications already known for the management of blood pressure in patients with severe preeclampsia or eclampsia.

The use of small doses has been proposed and studies have been carried out where satisfactory answers have been obtained, without evidence of complications for the mother, the neonate or the fetus that are attributed to the medication.

This absence of complications has been confirmed with the strict measurement of creatinine and urinary volumes during the first 24 hours in the case of the neonate that are attributed to the medication, for which treatment has been recommended.