Cannabinoids have dose-related antinociceptive effects in animals. This clinical study aimed to investigate whether a single oral dose of cannabis plant extract (Cannador; Institute for Clinical Research, IKF, Berlin, Germany) could provide pain relief with minimal side effects for postoperative pain.
Patients (aged 18-75 yr) were recruited and consented before surgery if patient-controlled analgesia was planned for provision of postoperative pain relief. Each patient received a single dose of 5, 10, or 15 mg Cannador if he or she had at least moderate pain after stopping patient-controlled analgesia. Starting with 5 mg, dose escalation was based on the number of patients requesting rescue analgesia and adverse effects. Pain relief, pain intensity, and side effects were recorded over 6 h and analyzed using tests for trend with dose.
Rescue analgesia was requested by all 11 patients (100%) receiving 5 mg, 15 of 30 patient (50%) receiving 10 mg, and 6 of 24 patients (25%) receiving 15 mg Cannador (log rank test for trend in time to rescue analgesia with dose P < 0.001). There were also significant trends across the escalating dose groups for decreasing pain intensity at rest (P = 0.01), increasing sedation (P = 0.03), and more adverse events (P = 0.002). The number needed to treat to prevent one rescue analgesia request for the 10-mg and 15-mg doses, relative to 5 mg, were 2.0 (95% confidence interval, 1.5-3.1) and 1.3 (95% confidence interval, 1.1-1.7), respectively. The study was terminated because of a serious vasovagal adverse event in a patient receiving 15 mg.
These significant dose-related improvements in rescue analgesia requirements in the 10 mg and 15 mg groups provide a number needed to treat that is equivalent to many routinely used analgesics without frequent adverse effects.
