Once the 20-year patent for a brand name drug expires, other manufacturers can make a generic version of the drug at a much reduced cost. Drug manufacturers can offer generics at a better price because far less is spent on advertising and costly clinical trials have already been conducted. Both generic and brand name drugs must meet the same quality and safety standards.
Nearly 45 per cent of all prescriptions filled in Canada use generic drugs and some hospitals use them exclusively, according to Health Canada. Generics must meet the same quality requirements as brand name drugs and have the same amount of medicinal ingredients. Fillers and coloring ingredients may differ but must be shown not to change the quality or effectiveness of the drug.
Authorized Generics are licensed from the original brand name manufacturer and are identical in both the active and inactive ingredients. Other generic drugs manufacturers develop their own formulations that may have different fillers but must meet bioequivalence testing standards. In rare cases, slow or extended release generic drugs have been reported as less effective than the brand name. For example, in 2012, the generic bupropion HCI ER 300 mg was found to not be therapeutically equivalent to the brand name Wellbutrin XL 300mg and as a result the generic drug was withdrawn from the distribution chain, according to a report by the FDA.
Some drugs known at NTI (narrow therapeutic index) drugs, have a narrow margin between what is considered safe and the dosage that is toxic. Warfarin (a blood thinner), digoxin (heart medication) and theophylline (lung treatment) are a few of the common generic drugs on this list. Small differences in dose or blood concentration in NTI drugs can lead to adverse reactions and as result, the FDA has proposed tightening the potency standards for these drugs.
If you have any questions about generic versus brand name drugs, ask your physician who will be able to note on the prescription whether or not a generic substitution is appropriate. It is also important to ask the pharmacist about how to take each medication; with or without food, how long you should take the drug, food or alcohol to avoid, side effects, potential for allergic reactions, how to store the medication and what to do in case of an incorrect dosage.
For more information about generic drugs, and to access the Orange Book (comparing brand name drugs with generics) visit the U.S. Food and Drug Administration at http://www.fda.gov/Drugs/ResourcesForYou/Consumers/QuestionsAnswers/ucm100100.htm.
Although manufacturers may deny this, it is the fillers in the generics that can react differently with other medications or with body chemistry from the original product. If one generic does not suit your body chemistry ask you Pharmacist to find another, and another, until there is one that suits you. We had to do this for my husband who was on a great many medications and a lot of fine-tuning had to be done to avoid bad reactions.