Eslicarbazepine acetate interacts in a beneficial manner with standard and alternative analgesics to reduce trigeminal nociception.

RATIONALE

Acute pain states in the trigeminal region (headaches, dental pain) fall into the most prevalent painful conditions. Standard analgesics (paracetamol/NSAIDs) represent the cornerstone of their treatment, whereas triptans are primarily used in migraine attacks. Due to limited efficacy and/or side effects of current treatments, identifying favorable combinations of available drugs is justified.

OBJECTIVES

Eslicarbazepine acetate (ESL) is a novel antiepileptic drug whose effectiveness against trigeminal pain was recently demonstrated. Here, we examined the interactions between ESL and several standard/alternative analgesics (paracetamol, propyphenazone, naproxen, zolmitriptan, and metoclopramide) in a model of trigeminal pain.

METHODS

The antinociceptive effects of orally administered ESL, standard/alternative analgesics, and two-drug ESL-analgesic combinations were examined in the orofacial formalin test in mice. The type of interaction between drugs was determined by isobolographic analysis.

RESULTS

ESL, analgesics, and two-drug ESL-analgesic combinations significantly and dose-dependently reduced nociceptive behaviour in the second, inflammatory phase of the test. Isobolographic analysis revealed that ESL interacted additively with paracetamol/propyphenazone/zolmitriptan and synergistically with naproxen/metoclopramide (with about a 4-fold and 3-fold reduction of doses in the ESL-naproxen and ESL-metoclopramide combination, respectively).

CONCLUSIONS

ESL interacted in a beneficial manner with several analgesics that are used for trigeminal pain treatment, producing synergistic interactions with naproxen/metoclopramide and additive interactions with paracetamol/propyphenazone/zolmitriptan. Our results suggest that combining ESL with analgesics could theoretically enable the use of lower doses of individual drugs for achieving pain relief.