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August 2010

Anticonvulsants and Suicide Risk
Findings from a recent study support the US Food and Drug Administration's 2008 conclusion that anticonvulsants increase the risk of suicidal ideation and behavior.

The Generic Medication Question
Variability in the bioavailability of generic medications can affect efficacy and tolerability in some patients.

Antidepressant-Induced Mania?
Evidence from a meta-analysis of controlled and open trials suggests that antidepressants increase the risk of a switch from depression into hypomania or mania in patients with bipolar disorder and in those with major depression.

Medications to Reduce Antipsychotic-Induced Weight Gain
The overall effect of medications as antidotes to antipsychotic-induced weight gain is modest; diet and exercise should be the first-line strategy.

In Brief
Veterans with PTSD Have Greater Risk of Dementia; Bupropion Safe and Effective Aid for Smoking Cessation in Schizophrenia

Smoking and Clozapine Levels
Elevations in plasma clozapine (Clozaril and others) concentrations following smoking cessation can be dramatic and potentially lead to serious toxicity.

The Generic Medication Question

August 2010

Of all drug prescriptions written in the United States, roughly 70% are filled with generic products. Most patients can be switched successfully from a brand name to a generic medicine with acceptable benefits and reduced costs.1

However, there can be problems with generic preparations. For a generic product to gain the approval of the US Food and Drug Administration, pharmacokinetic studies must show bioequivalence with the brand name product, typically in fewer than 40 healthy subjects. The maximum plasma concentration (Cmax), time to achieve that maximum concentration (Tmax), mean absorption time, and area under the concentration time curve (AUC; which measures overall drug exposure) are allowed to vary between 80% and 125% of those parameters with the brand name drug. This variability can affect efficacy and tolerability of some medications in some patients.

When generics are approved for widespread clinical use (ie, in "the real world"), kinetic variability can be even greater than the 80% to 125% allowed in the small number of healthy test subjects. Moreover, there may be considerable pharmacokinetic differences among different generic preparations. Problems have been reported for anticonvulsants, chlorpromazine (Thorazine and others), clozapine (Clozaril and others), venlafaxine (Effexor and others), and other agents when patients have switched from one to another preparation.

When patients change from a brand name to a generic preparation of the same medication, they should be informed that bioavailability can vary and that they may experience loss of efficacy or new (or re-emerging) side effects, which should be reported immediately. If clinical perturbations do occur, the doctor can then consider a return to the original product and/or a dosage adjustment. Patients who take generic products should also be aware that when the appearance of a product changes, it may indicate that the pharmacy has switched to a different generic manufacturer. The new product could produce higher or lower bioavailability at the same dosage, again with the potential for loss of efficacy or emergence of unwanted effects. Generic medicines save money but demand greater consciousness from clinicians and consumers.

1Ellingrod VL: How differences among generics might affect your patient's response. Curr Psychiatr 2010;9:31-32,38.