Chronic Pain - Anjuvant Medications - Antiepileptics

Anti-epileptic drugs AEDs are particularly useful for neuritic pain which is described as burning or stabbing. Control studies have established the efficacy of these particular agents in a host of conditions. Tegretol and Dilanton have proven to be effective in the treatment of tic douloureux, Shingles, and painful diabetic neuropathy.

More recently, studies indicate newer agents such as Neurontin, Lamictal, Klonopin, and Depakote have similar effectiveness. AEDs have also been used in pain stemming from multiple sclerosis, cancer, reflex sympathetic dystrophy and migraine.

Animals subjected to pain have a decreased pain response when treated with AEDs. AEDs may be combined with some of the other medications that have been previously discussed, such as anti-inflammatories, anti­depressants and even the opiates for additional pain relief.

The other type of commonly described pain is deep, aching noeiceptive pain. An example of this would be a back condition. This pain is not as responsive to this particular class of medications.

AEDs have been shown to be extremely safe and well tolerated. There have been many years of clinical experience with patients who have had epilepsy. Most of the side effects are dose related, although each agent has its own particular adverse effects which need to be listed.

Some of the newer medications like Neurontin appear to be better tolerated. Safe use during pregnancy is not known because the action mechanism is poorly understood. Animal studies however indicate low birth defect occurrences.  Anti-epileptic medications are believed to decrease the peripheral nerves from firing and therefore decrease harmful input into the central nervous system. They may increase certain types of neural transmitters such as GABA, which have a calming affect on the nerve cell itself.

I usually start with Tegretol as the first anti-epileptic drug and gradually increase the dose on a weekly basis, monitoring blood levels. However, sequential drug trials are often required before identifying an effective drug. Tegretol is about 70 percent effective. One needs to monitor the white blood cell count as well as liver enzymes. It has a high sedative side effect. Dilantin is usually my second drug of choice. Side affects with this particular medication in addition to sedation include gum and hair growth. Dilanton can be given all at once at bedtime, rather than in split doses. Neurontin has the advantage of minimal side effects. It requires no blood level tests and has virtually no drug interactions. This is also true of Lamictal. Depakote is particularly useful in treating migraine headaches.  Side effects include nausea and gastrointestinal complaints and one needs to follow blood count liver enzymes and pancreatic enzymes for rare, idiosyncratic effects.

Finally one can combine AEDs and achieve even better pain relief. More recently, medications such as Tegretol and Depakote have been utilized in bipolar disorders (manic depression) with excellent results. Klonopin has been utilized in the treatment of anxiety disorders and panic attacks. Neurontin and Lamictal have been utilized in the treatment of anxiety disorders and panic attacks. Neurontin and Lamictal have been proven effective in treating depression. These are useful properties when dealing with chronic pain patients. Obviously AEDs have additional beneficial affects beyond their pain relieving properties. In the next article I will discuss the opiates (narcotics).