OBJECTIVES: To assess the cost-effectiveness of using a lidocaine 5% medicated plaster (lidocaine plaster) in the treatment of post-herpetic neuralgia (PHN) in place of gabapentin from the perspective of the Scottish National Health Service. METHODS: A Markov model was constructed in TreeAge to calculate the costs and benefits of gabapentin and lidocaine plaster when used in primary care over a six-month time horizon in patients with PHN who have insufficient pain relief with standard analgesics and do not tolerate or are contraindicated to tricyclic antidepressants. The model structure allowed for differences in costs, utilities and transition probabilities between the initial 30-day run-in period and maintenance therapy and also took account of other medications that are added in alongside gabapentin/lidocaine plaster and those received by patients discontinuing gabapentin/lidocaine plaster. Most transition probabilities were based on clinical trials identified through a systematic literature review. Missing data, including resource utilization, were obtained from a Delphi panel and cost data from official price lists and tariffs. Utilities derived from a published study using the Health Utilities Index were adjusted for age and were supplemented and validated by the Delphi panel. RESULTS: The total cost for lidocaine plaster was £958 per patient, compared with £789 for gabapentin, although lidocaine plaster generated 0.292 quality-adjusted life-years (QALYs), compared with 0.248 for gabapentin. Lidocaine plaster therefore cost £3767 ($7370; 95% confidence interval: dominant, £13,415) per QALY gained relative to gabapentin. Probabilistic sensitivity analysis demonstrated that we can be 98.7% confident that lidocaine plaster is cost-effective relative to gabapentin at a £20,000/QALY threshold and 65% confident at a £5,000/QALY threshold. Scenario analyses and extensive one-way sensitivity analyses on all parameters including the time horizon confirmed the robustness of the results. CONCLUSION: The lidocaine 5% plaster is a highly cost-effective treatment for PHN in Scotland.