This will be simple. Prescription drugs that are needed for the health and well-being of a person will not be taxed. This does not include cosmetic drugs like Botox, or sexual performance drugs like Viagra.
Over the Counter drugs, and non-essential prescriptions will be charged at the standard tax rate of 30%. These drugs are not essential to well being, but still can be considered to make life comfortable.
Recreational drugs such as cigarettes. cigars, and marijuana (when legalize for recreational use) will be taxed at 45%.