Background Introducing a reimbursement restriction on lidocaine plaster prescribing in Ireland may have had unintended effects on prescribing of other analgesics with misuse potential. This study evaluates the impact of this policy on use, treatment intensification and initiation of opioids, gabapentinoids, and other analgesics. Methods This cohort study included adults eligible for Ireland's public health cover (approximately 33% of the population), using primary care dispensing data. The policy was fully implemented in December 2017, requiring individual patient approval for coverage of lidocaine plasters. In interrupted time series analysis, we examined change in level and trend of prescribing of other analgesics. In cohort analysis we compared lidocaine users to users of any other analgesic pre-policy and assessed outcomes of treatment intensification and initiation of opioids, gabapentinoids, and other analgesics in the three months post-policy. Results Among 1.65 million individuals, up to 1.4% were dispensed lidocaine plasters monthly pre-policy. Population-level use of other analgesics remained largely unchanged (except for topical agents). Compared to other analgesic users, lidocaine plasters users were significantly more likely to experience treatment intensification (adjusted risk ratio 1.47, 95%CI 1.38-1.57) of opioids after the policy, and initiation of strong (2.07, 1.85-2.30) and weak opioids (1.38, 1.21-1.59), controlling for baseline differences. Similar results were identified for gabapentinoid treatment intensification (1.26, 1.16-1.38) and initiation (1.34, 1.11-1.61), as well as for other analgesics. Conclusions This policy aimed at reducing low-value care was associated with greater opioid and gabapentinoid consumption, exposing patients to greater risk of drug-related harm from analgesic use and misuse.