You are viewing an older, archived article. There may be more up to date articles on this subject, try a new search

Essentials   PDF

Full colour PDF of the pages as they appeared in ‘best practice’.
 Printer friendly PDF.

Changing to a Generic Drug

Over recent years the worldwide market for generic drugs has grown faster than the pharmaceutical industry as a whole. This is largely due to strong efforts to contain drug costs by government agencies, as well as growing confidence in generic quality by both health professionals and consumers.1

When an innovator product (the original brand product) is replaced with a generic alternative there are many issues to consider. Physician attitude towards generic substitution is most often related to their general prescribing behaviour, perception of therapeutic efficacy, beliefs about generic drugs and previous experience with using generic alternatives, including any negative effects.2

Many issues confront patients undergoing a brand change to a generic substitute, including possible changes in therapeutic effect, side effects, practical use (e.g. size, shape, appearance) and managing their health condition.3 Increasing age is associated with less favourable attitude towards generic drugs. Patients are also often less accepting of using a generic drug to treat a serious disease.4

How do patients perceive the risk of changing to a generic drug?

One of the main barriers in changing brands of medication is the patient’s perception of risk.

A study conducted among American consumers of health care services found that 14% to 54% believed that generic prescription drugs were both less safe and less effective than the innovator product. Perception of risk was dependent on the severity of the medical condition being treated: patients with a heart condition perceived the highest risk.5 In another study there were significant differences found between pharmacological classes of drugs, with less acceptance associated with generic substitution of drugs acting on the central nervous system.6 A recent study conducted in Norway found that 36% of patients reported one or more negative experiences in relation to generic substitution. However although patients reported experiencing side effects and diminished therapeutic effect, there were no actual reports of clinical failure of the generic drugs.3

At the time of brand changing, many patients do not consider the generic drug to be an equal alternative to the innovator drug. However over time most patients do accept the change and the generic drug attains the status of the branded version. A study in the United States found that since 1979 an estimated 97% of patients in the state of New Jersey have agreed to use a generic substitute.1

Differences in appearance and brand loyalty

Generic drugs often differ from the innovator product in appearance and packaging which may cause anxiety and confusion. Patients receiving drug treatment for psychological disorders may be especially vulnerable to this.5 People often prefer to stick to a drug that they are already familiar with1, and may resist changing from a brand they know well to a generic equivalent, which may look or taste different.6 Prescriber habits and preferences may be influenced by informational constraints, loyalties to drug companies and desire to satisfy patients.4

Patient information programmes make brand changing easier

Patients who received information from their physician or pharmacist about generic substitution were more likely to have changed from the innovator product.3

A recent study based in Spain assessed acceptance of generic drugs for chronic conditions in primary care. Of the patients who received verbal information and written material, 98.9% agreed to receive a generic formulation. Individual educational intervention (that lasted less than five minutes in most cases) in patients with repeat prescriptions resulted in a high rate of generic acceptance. The intervention also helped to stimulate health practitioner’s knowledge of generic drugs.6

In a study involving a large general practice clinic in Scotland the influence of providing information to patients on their acceptance of generic drugs was tested. Patients were either sent an explanatory letter detailing the change or were informed when first collecting their repeat prescription. Satisfaction with the communication received was closely correlated with satisfaction about the change to the generic drug itself. After four months, generic prescribing increased from 37% to 58%.7

Although therapeutic problems are sometimes the most important adversity in a brand change, more often it is a failure of communication, which contributes largely to the lack of satisfaction. Patients are much more likely to be willing to try the new drug if they understand the reason for the change.7

These studies demonstrate that communicating effectively and acknowledging patient concerns is likely to result in a successful transition to a new drug brand.

Dissatisfaction usually centres around two main issues:

Power: patients feel weak or not in control of their health management if they perceive a change has been forced upon them.7

Communication: patients require empathy from their healthcare provider in order to feel satisfied, so they will accept major change if it is delivered in a manner which makes them feel valued. This also helps to avoid much of the negative feeling generated by the change itself, and enhances the patient/healthcare provider relationship, which can easily be damaged by these changes.7

Paroxetine Brand Change

In April 2007, Pharmac initiated a subsidy removal from the innovator form of paroxetine (Aropax) and in turn funded a generic form (Loxamine). Loxamine has met Medsafe’s bioequivalence standards, in accordance with international guidelines. In addition, this drug is already widely available throughout Europe, with sales for 2005 and 2006 in excess of 150 million tablets. No adverse effects of Loxamine have been reported to date.

However, the issues surrounding brand change can be more complex when the drug in question is used to treat a serious medical condition such as depression. The perceptions and attitudes of a patient receiving antidepressant therapy and how this may affect the way they accept a change to their drug therapy, both physiologically and psychologically, must be considered. Patients are often concerned that a change in their antidepressant medication may result in reduced clinical effect and/or increased side effects.

Given the bioequivalence of the two forms of paroxetine, the risk of a reduced response, increased side effects or the appearance of discontinuation syndrome due to a significant change in the dose received, is very unlikely. It is more likely that perceptions and attitudes to the change will be stronger determinants of response and acceptance than bioequivalence issues. GPs, practice nurses and pharmacists are in an ideal position to monitor patient feedback, response, side effects and attitudes to the change.

Components of the decision making process for accepting brand switching
Regulatory issues
Drug cost
Medication History
Side effects
Practical use
Managing Health
Prescribing behaviour
Therapeutic efficacy
Experience using generic drugs
Medical History


  1. Suh D. Trends of generic substitution in community pharmacies. Pharm World Sci 1999;21(6):260–65.
  2. Banahan B, Kolassa E. A physician survey on generic drugs and substitution of critical dose medications. Arch Intern Med 1997;157(18):2080–88.
  3. Kjoenniksen I, Lindbaek M, Granas A. Patients’ attitudes towards and experiences of generic drug substitution in Norway. Pharm World Sci 2006;28:284–289.
  4. Mott D, Cline R. Exploring generic drug use behaviour: The role of prescribers and pharmacists in the opportunity for generic drug use and generic substitution. Med Care 2002;40(8):662–74.
  5. Ganther J, Kreling D. Consumer perceptions of risk and required cost savings for generic prescription drugs. J Am Pharm Assoc 2000;40:378–83.
  6. Valles J, Barreiro M, Cereza G, Ferro J, Martinez M, Escriba J, et al. A prospective multicenter study of the effect of patient education on acceptability of generic prescribing in general practice. Health Policy 2003;65:269–75.
  7. Dowell J, Snadden D, Dunbar J. Changing to generic formulary: how one fundholding practice reduced prescribing costs. BMJ 1995;310:505–508.