Second-generation Antidepressants Very Similar But Have Different Side Effects

Manysecond-generation antidepressants, despite differences in drugclassification and cost, offer patients essentially the same benefitswith little variation in risks, University of North Carolina at ChapelHill researchers have found.

Such antidepressants includeselective serotonin reuptake inhibitors (SSRIs) and other drugs thataffect the activity of neurotransmitters in a selective way.

In apaper published online today (Sept. 19) and to be published in theOctober issue of the journal Annals of Internal Medicine, Dr. RichardA. Hansen and colleagues examined the effects of 10 commonly prescribedsecond-generation antidepressants. Those drugs included familiarbrand-name drugs such as Prozac, Zoloft, Effexor, Wellbutrin and Paxil.

Hansenis assistant professor of pharmacy at the UNC School of Pharmacy. Thestudy he led involved investigating the medications’ role in theinitial treatment of adults suffering from major depression bycombining and systematically analyzing data from 46 randomized,controlled trials.

Other authors, all at UNC, are Drs. GeraldGartlehner and Timothy S. Carey of the Cecil G. Sheps Center for HealthServices Research, Dr. Kathleen N. Lohr of the health policy andadministration department at the School of Public Health, and BradleyN. Gaynes of the School of Medicine’s psychiatry department. Carey,professor of medicine, directs the Sheps Center. Gartlehner isassociate director of the RTI-UNC Evidence-based Practice Center.

"Paststudies have compared the effectiveness of second-generationantidepressants with that of placebo or older treatments but have notsystematically evaluated how the second-generation agents compared toeach other," Hansen said. "Given the number of second-generationtreatments available, cost differences, widespread use and the generallack of consensus in how the drugs compare, our research can helppatients, clinicians and policy makers decide which drug is best."

Thebottom line was that one was about as good as another in terms ofeffectiveness, but the likelihood that patients experienced certainside effects differed between compounds, he said.

"Comparativeevidence on these drugs suggests that there are only minimaldifferences in efficacy, although some of the drugs come with anincreased risk of certain side effects," Hansen said. "Understandingthe likelihood of the side effects and matching this information withpatients’ lifestyle and preferences for anticipated side effects mayhelp improve drug treatment of depression.

"Although our studydid not specifically assess the impact of drug costs or differences indosing regimens on how patients fared, those factors also may beimportant determinants in drug selection," the scientist said. "That’sin the absence of patient preference or a clear choice for which agentis best for a given person."

Limitations of the study were thatpublished data from some trials was not as complete and comparable asresearchers would have preferred, Hansen said. Most data was fromtrials sponsored by drug companies, and questions remain as to howunbiased such studies are.

Support for the investigation came tothe Cecil G. Sheps Center for Health Services Research from the DrugEffectiveness Review Project, a collaborative program coordinated bythe Center for Evidence-Based Policy at the Oregon Health and ScienceUniversity.

In 2000, the economic burden of depression wasestimated to be $83.1 billion, Hansen said. Although drug treatmentdoes not work for all patients, drugs are usually considered the firstand potentially best treatment in part since primary care physiciansprescribe the majority of antidepressants in this country.