Antidepressants for Chronic Pain: Comparisons of the Old and New
Out with the old, in with the new; the world seems to revolve around this constant turnover. Sometimes new technology has a huge advantage, but sometimes the old stuff is just irreplaceable - like an old pair of jeans that fits just right and is soft from use.
Some medications from the past might be irreplaceable too. One such category of medications is the tricyclic antidepressants (TCA). Although they are rarely used to treat depression, they are still used to treat chronic pain. Lately, the new medications on the block called the serotonin-norepinephrine reuptake inhibitors (SNRIs) are grabbing the attention of physicians and patients around the world, leaving the TCAs nearly a forgotten memory. Is the replacement of the TCA by the SNRI justified? To answer that question, comparisons regarding effectiveness and safety must be made.
Both the old and the new antidepressants seem to be effective at treating chronic pain. Even some of the most difficult to treat pains respond to both types of anti-depressants. Post-herpatic neuralgia and fibromyalgia are both known to respond to tricyclic antidepressants. In fact, TCA's are still the preferred treatment for post-herpatic neuralgia.
Low back pain is a different story, a controversial story. Some studies show that Cymbalta (duloxetine), a newer antidepressant, does provide low back pain relief. Other studies do show very little improvement with the use of Cymbalta for chronic low back pain. On the other hand, painful diabetic peripheral neuropathy responds to the new antidepressant medications as well as the old ones. Based on the current information, depending on which painful condition is being treated, both the old and the new can be effective in treating chronic pain.
Sometimes a newer medication is preferred because it is least likely to cause side effects. The older tricyclic antidepressants are known to cause drowsiness, urinary retention, and dry mouth. But not all TCA's are created equally. Some TCA's like amitriptyline cause more side effects than others TCA's like desipramine. And sometimes the effective dose for treating pain with a TCA is so low that these dose-related side effects can be avoided. But it is hard to avoid side effects all together because even the newer antidepressants like Cymbalta cause side-effects like worsening depression, nausea, insomnia, tremor and hot flashes. Since both types of anti-depressant medications can lead to unwanted ill-effects, the new antidepressants do not seem to have a tremendous advantage over the older ones.
However, if one were to consider cost, the older medications have a clear advantage over the new "brand name only" drugs. With more and more individuals paying out-of-pocket for medications, cost is definitely a consideration these days. Once the patent on Cymbalta expires, more people might be able to afford it. For those who cannot afford Cymbalta, the old, cheap TCAs are definitely worth considering.
So before discounting the older generation of medications in favor of the flashy new ones hyped in marketing campaigns, consider efficacy, side effects and cost. Taking these factors into consideration when it comes to treating pain with antidepressant medications, the newer medications do not seem to have a clear advantage over the older ones. Both work for even the most difficult to treat painful conditions. Both cause side effects. Yet, the TCA is clearly cheaper. Maybe if the tricyclic antidepressants (TCA) were called the "tricylic analgesics" (TCA), they would be taken more seriously and not forgotten. Out with the old and in with the new is not always the best policy.