Chronic Pain - Adjuvant Medications - Antidepressants

In previous articles I have discussed an overview of chronic pain as well as anti-inflammatory medications. At this juncture, I would like to discuss adjuvant medications.

There are two basic types of chronic pain: the deep, aching, burning type (nociceptive) or the burning, stabbing, tingling pain (neuropathic). Adjuvant medications are most useful in this latter type. They are called adjuvant medications because they are indicated for medical conditions other than pain, but are useful for selected pain syndromes of the neuropathic type. Examples of neupathic pain syndromes include neuropathies. herpes zoster or shingles. RSD, various types of cancer pain and migraine.

Two major pharmacological categories; the anti-depressants and the anti-epileptics. As a neuropsychiatrist I have used these types of medications for over twenty years, and am quite familiar with their broad application. They are safe, non-habituating and effective.

There are several other categories which bear mentioning but are not as useful. These would include topically administered creams and ointments (Aspercream, Zostrix, EMLA), major tranquilizers or neuroleptics (Thorazine) muscle­ relaxants (Valium, Soma. Flexeril) anti-arrhythmic (Mexilietine) anti-hypertensives (Catapress).

When faced with a patient who complains of burning pain, typically the first medication that I tend to use is an anti-depressant. The older group of antidepressants would be the tricyclics (examples are Elavil. Sinequan. Tofranil). These have been the most widely used. Their mechanism of action is related to increasing brain transmitters which modulate pain, transmitters like serotonin, norepinephrine and endorphins. A person does not have to be depressed to experience relief of pain.

More recently, some of the newer antidepressants have been used. These include medications such as the SSRI's (Prozac, Paxil. Zoloft) or other new agents (Serzone, Effexor, Wellbutrin). In my experience, these newer medications are not as effective as the older tricyclics. They are, however worth a try primarily because they have less in the way of side effects and are better tolerated. It is advisable to start with a very low dose preferably at night and gradually increase over a month's period of time. This allows a patient to adjust to the medication.

Some of the side effects which occur with tricyclics include dry mouth, constipation, urinary hesitancy, sedation, blurred vision and weight gain. Tricyclics should be administered very carefully in patients with a history of cardiac disease and glaucoma, and they should not be combined with alcohol. CNS depressants or maoinhibitors. They can occasionally be combined with neuroleptics or major tranquilizers efficacious response.

Antidepressants are also particularly useful in chronic pain syndromes because of their antidepressant effect. Since eighty percent of pain patients are also anxious/depressed, the use of the appropriate medication also addresses this problem. Pain has a very steady draining effect on the organism and often times psychological components develop. If the associated depression is marked by agitation or insomnia, a more sedative agent is used (Elavil, Desyrel, Remeron). If associated anxiety with panic attacks or obsessions are prevalent, then the SSRI's; if severe lack of energy, then Vivactil or psychostimulants; if mood fluctuations, then Lithium.