CARBAMAZEPINE
Drug Treatments for Facial Neuralgias

| |Dosages | Side-effects | Medical References |
Patient Experiences | Lingering Questions | Links |

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DESCRIPTION

Trade names include Tegretol and Epitol.

Carbamazepine is an anticonvulsant (epilepsy medicine) and is .  generally the first medication to be tried in treating Trigeminal Neuralgia,  Atypical Trigeminal Neuralgia and Glossopharygeal Neuralgia. For typical TN, initial pain relief is often fast and quite adequate. Carbamazepine is so effective that it has sometimes been used as a marker for determining whether a patient has TN: if a patient does not respond to carbamazepine, then he probably does not have TN. However, this is not a completely certain marker. Carbamazepine may not be as effective for Atypical Trigeminal Neuralgia.

DOSAGES

Dosages are adjusted for each person individually, but usually vary between 200-1200 mg /day.

SIDE-EFFECTS

Carbamazepine is a dangerous drug if an extreme overdose is taken; death has been known to happen after very large overdoses. On the other hand, any drug is toxic when overdosed. If carbamazepine is used under a doctor's care, it is as safe as any other antiepileptic drugs. This does not mean that it is entirely harmless. The side effects can be unpleasant. When the treatment is begun, the side effects can include drowsiness, fatigue, dizziness, or nausea. (The nausea can often be partly controlled by taking the drug at mealtime). Extreme exhaustion and problems with memory and other mental activities are quite common. One of the most unpleasant and debilitating side effects is nystagmus (twitching of the eyes), which can make everyday life very difficult; however, nystagmus is a sign that the dosage has been increased too quickly, an should not be a permanent problem. Most of the other side effects should also pass once the body becomes used to the drug, which may take quite a while.

However, in the long term carbamazepine can have a variety of side effects. Various problems with vision may remain. A great many patients remain permanently exhausted and find their thought processes impaired. Memory loss is particularly common; since many patients are elderly, this is unfortunately often ignored as being due to dementia and aging. Nausea and dizziness is also possible. These side effects can be very unpleasant, and the patient should make the doctor aware of them. Having some side effects may be better than having TN pain, but the tradeoff is difficult.

There are two potentially serious side effects.

• Rash. If you develop a bad rash on taking carbamazepine, you should report this quickly to your doctor. The drug should then be stopped. It can be unsafe to stop an antiepileptic drug too quickly, so you should consult a doctor before you do this.
• Lowered blood counts. This can be quite dangerous and result in lowered immune system responses, for example. However, this can be monitored by routine blood testing every six months or so. In addition, very serious effects leading to death or disability are extremely rare. In other words, as long as testing is done properly, this is not something to be overly worried about.

MEDICAL REFERENCES

The professionals seem to have a somewhat mixed view of carbamazepine. All the literature we have seen is clear on the fact that carbamazepine is the first drug that should be tried. However, the side effects and long-term efficacy are matters that seem to divide the professionals.

[Walchenbach and Voormolen, 1996] say that "30%-75% do not obtain long term pain relief or experience side effects of the drugs". It is not clear what this exactly means.

[Browne et al,. 1990] note that carbamazepine has earlier had a bad reputation because of its effects on the blood count. However, experience has shown that carbamazepine is no more dangerous than other old antiepileptic drugs. (This statement does not necessarily apply to new antiepileptic drugs appearing after 1990). The authors note that carbamazepine kills no more people than ordinary drugs such as penicillin do; in that sense, it is completely "safe".

[Tomson et al., 1988] note that carbamazepine may affect vision more heavily than older epileptic drugs (primarily phenytoin). Blurred vision is particularly common. The effect seem to be dose-dependent, but it is not clear whether stopping the drug will cause vision to recover fully.

[Hojer et al., 1993] report on cases of serious damage or death after very heavy carbamazepine overdoses. The effects of carbamazepine poisoning are very unpleasant, but large overdoses are required. 

PATIENT EXPERIENCES

It seems that patient feelings toward carbamazepine are almost identical to the opinions of the experts: mixed.

Please keep in mind that the following comments do not represent a scientifically adequate cross-section of  patients, and the quotes chosen may reflect the bias of the author. In other words, the information here may be skewed and faulty, but on the other hand it is the closest thing at the moment to "the voice of the people"....

A few patients have suggested unofficial hints which may help to deal with the side effects.

	"...if you are having a bad time, get up in the night to make it the same number of hours between each dose." - Anonymous.
	"...also note that _everything_ interacts with tegretol..... remember even tylenol interacts with tegretol."  - Anonymous.
	"I have found that the time at which I take my medicine is critical. The best is to keep my first dose at 8 or 9 pm and the second at 6 or 7 am. "  -  Anonymous.
	"My solution to the zombie period was to take 3-4 tabs right before bed thereby sleeping through it."   -  "Gary". [Please note that some doctors might not consider this advisable].

LINGERING QUESTIONS
This section contains questions that the TNT authors have wondered and mused about but have been unable to answer. Should we ever find adequate answers to these questions, they will be added to the sections above. We welcome comments and possible answers to these questions.

• Drug Treatment vs. Surgery - Many of the sources we have read have very differing views of carbamazepine. Surgeons seem to be most opposed and advocate surgery as soon as possible; neurologists are not so sure. This is not a problem in itself; medicine has and always will have differing schools of thought. Both schools have their points, and in any case time will show which one is stronger. However, does this mean that the answer you get will depend on who you ask?
• Dosage Levels - Many sources would claim that doses above 1000 mg/day are not going to provide any additional relief. However, our patient experiences tell of patients taking up to 2000 mg/day with no pain relief ["Julie"]. If you are one of these patients, should you perhaps ask your doctor to reconsider your medication?
• Blood Tests - Most sources recommend blood tests every six months or so. However, in practice not all doctors seem to agree, since the effects on blood levels are not as dramatic as was thought earlier. In practice, we know of patients who are never monitored. If you are one of these patients, perhaps you should raise the matter with your doctor? The blood tests can be somewhat expensive, but money should not be allowed to be a factor in something like this.

LINKS

IMH Monograph: Carbamazepine.
A more complicated but thorough description requiring some knowledge of medical terminology.

RxList: Carbamazepine.
Also quite complicated, but has good warnings about possible side effects.

Carbamazepine
Excellent drug profile in easy-to-understand language from the US Pharmacopea database.  Dosages are listed for adults, teens, children ages 6 to 12 and children up to age 6.