Pharmacology Methotrexate mechanism of action: A Inhibit dihydrofolate reductase B Stimulate dihydrofolate reductase C Inhibit tetrahydrofolate reductase D Stimulate tetrahydrofolate reductase 💡 Explanation Methotrexate mechanism of action: ✓ Correct Answer: A. Inhibit dihydrofolate reductase