Carbamazepine for Trigeminal Neuralgia

• Trigeminal neuralgia (TN), also known as tic douloureux, is a distinctive facial pain syndrome that may become recurrent and chronic. 
• It is characterized by unilateral pain following the sensory distribution of cranial nerve V (typically radiating to the maxillary or mandibular area in 35% of affected patients) and is often accompanied by a brief facial spasm or tic.1

Carbamazepine

• The only approved medication by FDA for the treatment of Trigeminal Neuralgia 
• Pharmacologic therapy is the initial treatment of most patients with classic TN (ie, TN that is idiopathic or caused by neurovascular compression). 
• Surgery is reserved for patients who are refractory to medical therapy.
• Carbamazepine is the best studied treatment for classic TN and is established as effective. 
• Side effects can be a problem but are generally manageable, particularly if low doses are prescribed initially with gradual titration.2

Dosing

Ref: Clinical Pharmacokinetics Pharmacy Handbook,2015

Ref: https://www.drugs.com/dosage/carbamazepine.html

Therapeutic Drug Monitoring(TDM)

• Sampling time: 30 minutes before the next dose.

 Ref: Clinical Pharmacokinetics Protocol. PSD, Sabah State Health Department. 

Ref: Clinical Pharmacokinetics Pharmacy Handbook, 2015

Toxic level

• Lexicomp: >15mcg/ml
• Medscape: The toxic concentration/critical laboratory value is greater than 30-40 mg/L

Ref: Clinical Pharmacokinetics Pharmacy Handbook, 2015

References

1. http://emedicine.medscape.com/article/1145144-overview
2. www.uptodate.com
3. Clinical Pharmacokinetics Pharmacy Handbook, 2015
4. https://www.drugs.com/dosage/carbamazepine.html