The most popular antidepressants may not be best choice for frail elderly
The most popular class of antidepressants, known as selective serotonin reuptake inhibitors, or SSRI’s, may not be the best choice for seniors. Instead, a low dose of the older generation anti-depressants known as tricyclics, may be the safer option.
SSRI’s include such well-known drug superstars as Prozac, Paxil and Zoloft, are generally considered safe, and are widely prescribed. A lesser known reason for their popularity among doctors is that most of them do not carry an overdose potential; thus a depressed patient cannot take a lethal dose in a moment of suicidal despair.
However, a new British study appearing in the Aug. 2 issue of the British Medical Journal (BMJ) finds that an older group of drugs known as tricyclic antidepressants may be safer in people over the age of 65. Several factors need to be considered when choosing an antidepressant, possible side effects being just one of them.
"The choice of class of antidepressant is a complex decision, and some evidence is still lacking to help with that choice in older patients," said study author Carol Coupland, associate professor of medical statistics at the University of Nottingham. "Low-dose [tricyclic antidepressants] may be more suitable in frail elderly patients at increased risk of falls and fracture."
SSRI’s are widely prescribed in seniors with depression, but few trials have actually looked at the safety and effectiveness of these drugs in this group of people, added Angie Hochhalter, an assistant professor of internal medicine at Texas A&M Health Science Center College of Medicine. She was not involved in the new research.
Coupland's team looked at prescription data on more than 60,000 patients aged 65 to 100 who had been newly diagnosed with depression. Ninety percent of patients had received one or more prescriptions for antidepressants, 55 percent of those for an SSRI and 32 percent for a tricyclic antidepressant. The rest were on other antidepressants.
Seniors who were on SSRIs had a higher risk of dying, having a stroke, falling, breaking a bone and seizures compared with those not taking any antidepressant. Over the course of a year, 10.6 percent of seniors taking an SSRI died vs. 8 percent of those taking tricyclics and 7 percent of those taking no antidepressant at all. More than 11 percent of those taking other antidepressants died.
Among SSRIs, Effexor, Remeron (mirtazapine) and Desyrel (trazodone) showed the highest risks.
The researchers noted that the risks of injury or death were highest in the month after starting the drugs and the after discontinuing the drugs.
One confounding factor in the study was that tricyclics were prescribed at low doses – lower than the standard therapeutic doses in the adult (but not elderly) population.
Children and the elderly always pose special population segments in terms of their reactions to medication. While children can sometimes exhibit paradoxical reactions (reactions contrary to the standard adult reaction, such as excitement versus sleepiness), the elderly are more frequently much more dose-sensitive. This is generally attributed to an older individual’s slowed or impaired metabolism or less-than-optimal liver function. Thus, low dose tricyclics often have comparable therapeutic effects to standard doses in younger adults.
The study does not imply that SSRI’s should be avoided at all costs. The choice of an anti-depressant is a very complex decision, and those for whom SSRI’s work should not discontinue. The important point is that the injury and death risk rises upon commencement of the drug and upon its discontinuation, suggesting that the cause lies not in its mechanism of action but on how it affects balance and spatial orientation.
Dr. Coupland added that, "careful monitoring is needed, particularly during the first month of treatment, whichever class is prescribed."