Table 6.
Schematic overview of studies involving codeine in human experimental pain models
| Reference | Dose | Model | Findings | |
|---|---|---|---|---|
| Acute models | [99] (n= 18) | 125 mg orally | Pressure algometry (phalanx), PTT, single and repeated electrical sural nerve stimulation PDT, PTT Cold pressor test peak pain AUCVAS, discomfort | Pain and discomfort for all stimulations was decreased |
| [104] (n= 27) | 100 mg orally | Heat skin stimulation and deep pressure PDT, PTT Cold pressor test VAS, peak pain, AUCVASSural nerve electrical stimulation, PDT, PTT stimulus response curve | Heat from electrical, thermal and pressure ↔, cold pressor, peak pain ↓ | |
| [108] (n= 12) | 60/120 mg orally | Cold pressor test VAS, level of ‘bothersomeness’ | VAS ↓ (not dose-related), level of bothersomeness ↔ | |
| [107] (n= 14) | 75 mg or 100 mg orally | Cold pressor test AUCVAS, peak pain, discomfort (VAS) Heat skin stimulation and deep pressure PDT, PTT | Peak pain and discomfort in cold pressor test ↓ (only extensive metabolizers) AUCVAS and heat and pressure (PDT and PTT) ↔ | |
| [108] (n= 48/32) | 60 mg orally | Electrical and heat skin stimulation (PDT, PTT (electrical) | Pain from both modalities was decreased |
In the column ‘model’ the method for pain assessment is normal font, and the method for pain induction is bolded. Abbreviations: pain detection threshold (PDT), pain tolerance threshold (PTT), area under curve (AUC), visual analogue scale score (VAS), hyperalgesia (HA).