The provision of adequate analgesia after an invasive procedure or for general pain management is an important component of laboratory animal care. Choosing the appropriate analgesic requires careful consideration by the investigators, the veterinary team and the institution's ethical review committee. Sustained-delivery analgesics are superior to analgesics with short durations of action because they do not need to be administered multiple times, reducing handling-induced stress to the animal, and they provide sustained plasma concentrations of the analgesic over the treatment period. The author reviews analgesic formulations that have durations of action longer than 12 h and up to 72 h. These options should be considered when appropriate for particular procedures and animal species.