Tolnaftate is an over-the-counter anti-fungal agent mainly used to treat jock itch, athlete's foot and ringworm. It can come as a cream, powder, spray, or liquid aerosol. Tolnaftate is diffuses into the fungal cell. The exact mechanism of action for tolnaftate is unknown, however, it is believed to prevent the synthesis of ergosterol through inhibition of squalene epoxidase. Squalene monooxygenase catalyzes the synthesis of (S)-2,3-epoxysqualene from squalene. Since it is inhibited, it cannot continue on to synthesize lanosterol which is essential in the synthesis of ergosterol. Without ergosterol in the cell membrane, the cell membrane sees increased permeability which allows intracellular components to leak out of the cell. Ergosterol is also essential in cell membrane integrity so without that, eventually the cell collapses and dies.. The fungal cell also cannot synthesize new cell membranes for new fungus cells if there is no ergosterol. The inhibition of squalene monooxygenase also causes a buildup of squalene which is toxic to the fungal cell.

Tolnaftate Pathway References