Debrisoquine

Debrisoquine is a derivative of guanidine. It is an antihypertensive drug similar to guanethidine. Debrisoquine is frequently used for phenotyping the CYP2D6 enzyme, a drug-metabolizing enzyme.
Debrisoquine has been identified as a inhibitor of TMPRSS2 protease, which is involved in the viral entry process of SARS-CoV-2. In a laboratory study, it showed antiviral activity by blocking the ability of the virus to enter human lung cells.
The guanidine part of the molecule also appears in guanoxan and guanadrel. The 7-bromo analog of debrisoquine is called guanisoquin.