Bromhexine-d 3 (hydrochloride) is deuterium labeled Bromhexine (hydrochloride). Bromhexine hydrochloride is a potent and specific TMPRSS2 protease inhibitor with an IC50 of 0.75 μM. Bromhexine hydrochloride can prevent and manage SARS-CoV-2 infection. Bromhexine hydrochloride is an autophagy agonist. Bromhexine hydrochloride is a mucolytic cough suppressant and has the potential for a range of respiratory conditions.