Tolerance: Generic drugs
Most people taking stimulants will be using a generic version of the drug. Because there are a number of generic stimulant manufacturers, patients may receive a different generic if, for instance, they change pharmacies or the pharmacy changes distributors. The FDA’s requirements for bio-equivalence can allow for a wide variation in drug composition, leading to disparities in the rate and amount of drug absorbed. Thus, the switch from one generic stimulant to another may cause a real and noticeable decrease in the drug’s effectiveness.
Therefore, one of the first things to examine when drug efficacy appears to have changed is whether the pill looks different than usual. It might even be necessary to ask the pharmacist who the manufacturer of the current and previous prescriptions was. (They will generally have this information on file, since these are controlled substances.) Often, simply switching back to their original generic brand will solve the problem. For this reason it is a good idea to keep track of which generic manufacturer you prefer, in case you need to switch pharmacies for any reason.
Last updated 12/2/17