CANPOP Dose Finding

An open label study: would a single oral dose of a cannabis plant extract (Cannador) help to provide pain relief after surgery.

Finding the right dose of a cannabis extract to provide pain relief

What was this study about?

The CANPOP study aimed to find out whether a single oral dose of a cannabis plant extract (Cannador) could help to provide pain relief after surgery. 

The dose of Cannador was based on the amount of tetrahydrocannabinol (THC) present – one of the active ingredients in cannabis. The CANPOP Dose Finding Study aimed to find out what a safe and effective dose of THC would be. This was an open label study.

See also the CANPOP study.

What difference did this study make?

Rescue analgesia was requested by all 11 patients (100%) receiving the 5mg dose, 15 of the 30 patients (50%) receiving the10mg dose, and 6 of the 24 patients (25%) receiving the 15mg dose.

The study demonstrated a clear relationship between the dose of Cannador and the proportion of patients asking for rescue analgesia. The number of patients needed to be treated (NNT) with Cannador to prevent one request for rescue analgesia was 2.0 for the 10mg dose and 1.3 for the 15mg dose (relative to the 5mg dose). The study was stopped early after a serious adverse event in one patient who received a 15mg dose of Cannador.

Who funded the study?

The Medical Research Council.

When did it take place?

This study began recruiting patients in 2001. It closed to recruitment in 2003.

Who was included?

All types of surgical patients requiring pain relief overnight using patient controlled analgesia (PCA) with morphine following surgery. After stopping PCA, each patient swallowed a single dose of Cannador. Starting with a 5mg dose of THC, the decision to increase the dose for the next patient was based on the number of patients who has asked for rescue medication for pain relief on the current dose.