Captopril, sold under the brand name Capoten among others, is an angiotensin-converting enzyme (ACE) inhibitor used for the treatment of hypertension and some types of congestive heart failure.

Due to the adverse drug event of causing hyperkalemia, as seen with most ACE Inhibitors, the medication is usually paired with a diuretic.

This is consistent with the observation that animal screening models indicate putative antidepressant activity for this compound, although one study has been negative.

[9] Adverse effects of captopril include cough due to increase in the plasma levels of bradykinin, angioedema, agranulocytosis, proteinuria, hyperkalemia, taste alteration, teratogenicity, postural hypotension, acute renal failure, and leukopenia.

[10] Except for postural hypotension, which occurs due to the short and fast mode of action of captopril, most of the side effects mentioned are common for all ACE inhibitors.

[13][14][15] In the late 1960s, John Vane of the Royal College of Surgeons of England was working on mechanisms by which the body regulates blood pressure.

Squibb filed for U.S. patent protection on the drug in February 1976, which was granted in September 1977, and captopril was approved for medical use in 1980.

Ondetti, Cushman, and colleagues built on work that had been done in the 1960s by a team of researchers led by John Vane at the Royal College of Surgeons of England.

BPF was later found to be a peptide in the venom of a lancehead viper (Bothrops jararaca), which was a “collected-product inhibitor” of the converting enzyme.

The drug became a generic medicine in the U.S. in February 1996, when the market exclusivity held by Bristol-Myers Squibb for captopril expired.

A chemical synthesis of captopril by treatment of L-proline with (2S)-3-acetylthio-2-methylpropanoyl chloride under basic conditions (NaOH), followed by aminolysis of the protective acetyl group to unmask the drug's free thiol, is depicted in the figure at right.