OBJECTIVE

To determine the factors affecting the effectiveness of carbamazepine therapy for trigeminal neuralgia.

MATERIAL AND METHODS

We analyzed 22 patients who underwent surgery for trigeminal neuralgia between 2019 and 2021. All patients received preoperative carbamazepine therapy.

RESULTS

The study included 18 (81.8%) women and 4 (18.2%) men aged 43—74 years (median 62 years). Left-sided pain was observed in 10 (45.5%) cases, right-sided pain — in 12 (54.5%) cases. Duration of disease ranged from 18 to 420 months (median 102.2 months). Duration of carbamazepine therapy varied in the same range (median 78 months). The dosage of carbamazepine was 400—2000 mg (mean 913 mg). Ten patients (45.5%) had comorbidities. In 12 (54.5%) cases, compression was caused by superior cerebellar artery, in 10 (45.5%) cases — by anterior inferior cerebellar artery. In 8 (36.4%) cases, compression was also caused by vein in addition to artery. Older patients received less doses of the drug (p=0.048, r=0.43). There were significant differences in VAS scores of facial pain between men (mean 9.5) and women (mean 6.8) (p=0.02). We failed to determine parameters that could be related to dosage of carbamazepine and VAS score of pain syndrome. We also found no factors associated with serum concentration of carbamazepine before surgery and after simultaneous withdrawal of the drug.

CONCLUSION

Serum concentration of carbamazepine is not informative for correction or selection of dosage required for facial pain relief. Intensity of facial pain is not associated with any anthropometric, anatomical or metabolic processes, as well as dosage of carbamazepine. Carbamazepine should be prescribed in low dosages (100 mg twice a day) with gradual increase until acceptable analgesic effect is achieved without side effects.