Antiepileptics

Dimitris Papadopoulos MD Fellow Of Interventional Pain Practice (FIPP)

Updated 01 March, 2011

Antiepileptics are very effective in the treatment of various neuropathic pain syndromes.
Carbamazepine (TEGRETOL) is an antiepileptic drug approved by the American Food and Drug Administration (FDA) to treat pain in trigeminal neuralgia.

Gababentin (NEURONTIN) has been approved by FDA for postherpetic neuralgia.

Pregabalin (LYRICA) is a newer antiepileptic approved by FDA relieving postherpetic neuralgia, diabetic neuropathy and, recently, fibromyalgia.

Drugs of this group do not cause addiction but their discontinuation should be gradual and under the therapist physician’s guidance, because sudden interruption may be hazardous.

Common side-effects of antiepileptics are drowsiness, poor balance, peripheral oedema, dizziness. Side-effects are less intense when there is slow increase of dosage and they are eliminated over time.

  • Carbamazepine (Τegretol) The most effective drug for trigeminal neuralgia. It may cause liver complications and affect white blood cell count.
  • Valproic acid (Depakote®): Administered for headache and neuralgia. It may affect blood platelet count.
  • Gabapentin (Neurontin®): Administered for neuropathic pain. Quite easy and safe profile. In high dosages, it may cause mental confusion.
  • Lamotrigine (Lamictal®): It can be effective in pain resistant to carbamazepine. Indicated for trigeminal neuralgia and central neuropathic pain. + side-effects: dizziness, constipation , nausea and reduced vigilance
  • Pregabalin (Lyrica®) Effective in postherpetic neuralgia, diabetic neuropathy and recently fibromyalgia
  • Topiramate (Topamax®) It is a generally well tolerated drug. Probable side-effects: confusion, dizziness, fatigue, coordination and concentration disorders. It may be effective in neuropathic and sympathetic pain. Probable side-effects: loss of appetite, loss of weight, peculiar sensations and suicidality.
  • Levetiracetam (Keppra®) Potenitally used in neuropathic pain
  • Oxcarbazepine (Trileptal®) Administered in neuropathic pain and particularly trigeminal neuralgia -instead of carbamazepine- for it presents fewer side-effects.

(Neurontin)

Common side-effects: light sedation, dizziness and headache. More rare side-effects are weight gain, fluid retention, abdominal pain and nausea.

It is administered  three times daily with gradual dose increase within several days and weeks. The maximum allowed dose in Great Britain is 1800mg, while in the U.S.A.  usual doses range from 2400-3600 mg daily. The drug is accumulated in cases of renal failure, where lower dosage is recommended with close follow-up by the therapist physician.

NORMAL RENAL FUNCTION
TIME MORNING
NOON
NIGHT
STEP 1
- - 300 mg
STEP 2 300 mg - 300 mg
STEP 3 300 mg 300 mg 300 mg
STEP 4 300 mg 300 mg 600 mg
STEP 5 600 mg 300 mg 600 mg
STEP 6 600 mg 600 mg 600 mg
  • Every step may last 3-7 days according to the occurring side-effects
  • These doses can increase or reduce depending on each patient’s response to the therapy and  the potential side-effects.
RENAL DYSFUNCTION
TIME MORNING NOON NIGHT
STEP 1
- - 100 mg
STEP 2 100 mg - 100 mg
STEP 3 100 mg 100 mg 100 mg
STEP 4 100 mg 100 mg 200 mg
STEP 5 200 mg 100 mg 200 mg
STEP 6 200 mg 200 mg 200 mg

PREGABALINE (Lyrica)

Pregabaline acts on speficic type calcium channels and have a more drastic effect on these channels than gabapentine. It has predictable intestinal absorption, rapid action onset and presents a more stable profile from patient to patient. It seems to relieve neuropathic pain even with the initial dose of 150mg daily. If necessary, the dose can gradually increase up to 600mg daily.

The dose should be reduced in the elderly and patients with low renal function, due to the fact that 98%  of the drug is excreted in the urine.

It has been observed that the low amitryptiline dose has a positive effect on quality of sleep. It is usually administered twice daily. Common side-effects are dizziness, drowsiness and fluid retention.

NORMAL RENAL FUNCTION
TIME MORNING NIGHT
STEP 1 75 mg 75 mg
STEP 2 150 mg 150 mg
STEP 3 300 mg 300 mg
  • Step 1 is the starting dose.
  • Step 2 follows, if necessary, 3-4 days later.
  • Step 3 follows 7 days later
  • These doses can increase or reduce depending on each patient’s response to the treatment and potential side-effects.
RENAL DYSFUNCTION
TIME MORNING
NIGHT
STEP 1 25 mg 25 mg
STEP 2 50 mg 50 mg
STEP 3 75 mg 75 mg

CARBAMAZEPIN (Tegretol)

Carbamazepin (Tegretol) has useful membrane stabilization properties. It is essential to gradually increase the dose by 100mg . The common dose for adults is 200mg X 3 daily.

Doses over 600mg daily are likely to cause drowsiness and ataxia.

The common dose for the elderly is 100mg X 2 daily.