Lisinopril is ranked as one of the most widely prescribed drugs in the United States. It is an angiotensin-converting enzyme inhibitor (ACEi). The first ACEi was a drug called captopril (Capoten, Squibb). It was derived from the venom of the Brazilian pit viper called Jararaca (Bothrops jararaca). The venom kills by causing hemorrhaging and anticoagulation effects. However, there was a peptide found in the venom that blocked the ACE.
After captopril was discovered, scientists at the Merck Co. made another ACEi called enalapril to overcome the bad taste and rashes caused by captopril. Enalapril was a prodrug and was converted to enalaprilat, the active metabolite. The Merck scientists experimented with the enalapril structure by adding amino acids to different parts of the molecule. It turned out that by adding lysine to the molecule added to its activity and retained its bioavailability. This was how it got its generic name lisinopril. It was approved for hypertension in 1987 and congestive heart failure in 1993.
However, Merck was achieving strong sales with its enalapril (Vasotec) and did not want to diminish their sales They entered into a co-marketing agreement with Zeneca (now AstraZeneca). The Zeneca lisinopril was called Zestril. Merck still marketed lisinopril as Prinivil but did not push the drug as much as Zeneca did its Zestril. The US patent expired in 2002 and has been available as a generic drug, oftentimes being combined with a diuretic in the same tablet
Source: https://en.wikipedia.org/wiki/Lisinopril#History
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