Anti-epileptics for neuropathic pain

Gabapentin is licensed for use in neuropathic pain of any cause:

• increase the dose according to the following regimen: 300 mg on day 1, then 300 mg twice daily on day 2, then 300 mg 3 times daily on day 3, then increase according to response in steps of 300 mg daily (in 3 divided doses) to max. 1.8 g daily
  
• in trials pain scores show that shows that gabapentin reduces pain and improves some quality-of-life measures in patients with a wide range of neuropathic pain syndromes (Serpell, Pain 2002, 99(3):557-66)

Carbamazepine and phenytoin are licensed for the treatment of trigeminal neuralgia:

• phenytoin is reserved for patients who fail to respond to carbamazepine
• trial evidence supports carbamazepine rather than phenytoin

For NICE guidance regarding management of chronic pain (pain that lasts for more than 3 months) then see linked item.

In this guidance (4), NICE state that antiepileptic drugs including gabapentinoids should not be initiated to manage chronic primary pain in people aged 16 years and over.

Notes:

• when withdrawing or switching treatment, taper the withdrawal regimen to take account of dosage and any discontinuation symptoms (3)
  
  
• MHRA advice on valproate: In April 2018, we added warnings that valproate must not be used in pregnancy, and only used in girls and women when there is no alternative and a pregnancy prevention plan is in place. This is because of the risk of malformations and developmental abnormalities in the baby (3)
  
  
• because of a risk of abuse and dependence, pregabalin and gabapentin are controlled under the Misuse of Drugs Act 1971 as class C substances and scheduled under the Misuse of Drugs Regulations 2001 as schedule 3 (as of 1 April 2019) (3)

Reference:

• (1) West Midlands Palliative Care Physicians (2007). Palliative care - guidelines for the use of drugs in symptom control.
• (2) Drug treatment of neuropathic pain. Drug Therap Bull 2000;38(12): 89-93.
• (3) NICE (July 2019). Neuropathic pain in adults: pharmacological management in nonspecialist settings
• (4) NICE (April 7th 2021). Chronic pain (primary and secondary) in over 16s: assessment of all chronic pain and management of chronic primary pain