Tolerance to benzodiazepines among long-term users in primary care.

BACKGROUND Tolerance towards the effects of benzodiazepines is observed in various animal and human studies. Therefore, it is assumed that patients who use benzodiazepines for a longer period of time need to increase their dose over time to experience the same effect. OBJECTIVE To observe whether long-term benzodiazepine users increase their dose over time. METHODS From the Dutch National Information Network of Family Practices, a group of long-term benzodiazepine users was identified. This group was divided into an incident long-term benzodiazepine users group (N = 113) and a prevalent long-term benzodiazepine users group (N = 992). Long-term use of benzodiazepines was defined as usage for at least 6 months. The main outcome was a change in prescribed dose from baseline until 24 months after baseline. Linear regression analysis was performed to evaluate dose change. RESULTS Neither incident long-term benzodiazepine users nor prevalent long-term benzodiazepine users were prescribed increasing dosages during follow-up. CONCLUSION There is no increase in prescribed dose among long-term users, as might be expected due to the development of tolerance to the effects of benzodiazepines.