Comparative study of clinical efficacy of amitriptyline and pregabalin in postherpetic neuralgia.

The most common complication of herpes zoster in immunocompetent patients is postherpetic neuralgia, which is very difficult to treat. Significant beneficial effects have been found for amitriptyline, gabapentin, pregabalin, carbamazepine, sodium valproate, oxycodone, corticosteroid, topical capsaicin, tramadol, etc. The aim of this open randomized comparative study was to demonstrate clinical efficacy of amitriptyline and pregabalin. The study included 50 patients, 32 (64%) male and 18 (36%) female, randomized to receive either amitriptyline or pregabalin (n=25 each). Amitriptyline was administered in a dose of 25 mg once daily and pregabalin in a dose of 75 mg twice daily. Inclusion criteria were as follows: postherpetic neuralgia of more than 1 month duration; pain of at least moderate severity; and patient age 40 years or older and no pregnancy. Patients with a history of any serious diseases (renal, cardiac, hepatic or seizure) were excluded. Total treatment period spanned 8 weeks, with patient follow up visits at 2, 4 and 8 weeks to assess the degree of improvement in pain perception and any adverse reaction. Patients with four herpes zoster types were included in this study, of which thoracic type predominated (54%). Other types were cervical in 12 (24%), trigeminal in 8 (16%) and lumbosacral in 3 (6%) patients. Prodromal symptoms before herpes zoster were reported by 66% of study patients. Satisfactory improvements of pain perception at the end of 8 weeks (>75%) were noticed in pregabalin group, which was statistically significant (χ(2)2=10.08; P<0.05). Dry mouth was the commonest complication in amitriptyline group and dizziness in pregabalin group. More importantly, none of the patients stopped treatment due to adverse reaction. In conclusion, therapy with pregabalin is better compared to amitriptyline in postherpetic neuralgia patients. However, a similar study in a larger sample is required to validate the present findings.