Table 3.
Mean (SD) plasma levels of delta-9-THC and metabolites, and comparisons among current, ex-, and naïve cannabis users
| Cannabis use, N | Delta-9-THC
|
11-OH-THC
|
THC-COOH
|
CBD
|
CBN
|
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Second vaporization administrationa | Recovery periodb | Second vaporization administration | Recovery period | Second vaporization administration | Recovery period | Second vaporization administration | Recovery period | Second vaporization administration | Recovery period | |
| 2.9% | ||||||||||
| All users | 25.0 (19.1) | 0.9 (2.3) | 1.7 (1.9) | 0.2 (0.7) | 18.8 (33.0) | 17.5 (32.7) | 0.0 (0.0) | 0.0 (0.0) | 0.6 (1.2) | 0.0 (0.0) |
| Current users (15) | 33.0 (21.7) | 2.2 (3.3) | 2.6 (1.8) | 0.5 (1.1) | 43.6 (40.9) | 41.0 (41.8) | 0.0 (0.0) | 0.0 (0.0) | 1.1 (1.6) | 0.0 (0.0) |
| Ex-users (18) | 19.1 (14.9) | 0.0 (0.0) | 0.7 (1.1) | 0.0 (0.0) | 1.1 (2.3) | 1.1 (1.9) | 0.0 (0.0) | 0.0 (0.0) | 0.2 (0.7) | 0.0 (0.0) |
| Naïve (4) | 21.2 (19.9) | 0.0 (0.0) | 2.6 (3.0) | 0.0 (0.0) | 5.6 (4.0) | 3.3 (3.4) | 0.0 (0.0) | 0.0 (0.0) | 0.6 (1.2) | 0.0 (0.0) |
| P-value | 0.1684 | 0.0023, Cur > Ex | 0.0115, Cur > Ex | 0.0978 | 0.0001, Cur > Ex | 0.0009, Cur > Ex | NA | NA | 0.1925 | NA |
| 6.7% | ||||||||||
| All users | 50.0 (39.7) | 1.2 (2.8) | 3.2 (3.5) | 0.4 (1.2) | 21.2 (32.0) | 19.6 (32.6) | 0.9 (1.6) | 0.0 (0.0) | 0.5 (1.3) | 0.0 (0.0) |
| Current users (16) | 54.3 (32.8) | 2.5 (4.0) | 3.9 (3.8) | 0.9 (1.7) | 43.6 (39.8) | 41.6 (42.2) | 0.7 (1.2) | 0.0 (0.0) | 0.4 (1.1) | 0.0 (0.0) |
| Ex-users (18/19)c | 48.8 (47.3) | 0.2 (0.6) | 2.4 (3.3) | 0.0 (0.0) | 4.7 (4.1) | 3.8 (4.5) | 1.0 (1.4) | 0.0 (0.0) | 0.4 (1.1) | 0.0 (0.0) |
| Naïve (4)d | 33.9 (27.7) | 0.6 (1.2) | 3.8 (3.5) | 0.0 (0.0) | 5.6 (4.6) | 7.2 (8.5) | 1.6 (3.2) | 0.0 (0.0) | 1.4 (2.8) | 0.0 (0.0) |
| P-value | 0.4222 | 0.0411, Cur > Ex | 0.4387 | 0.0184, Cur > Ex | 0.0006, Cur > Ex | 0.0011, Cur> Ex | 0.8007 | NA | 0.7486 | NA |
Notes:
Second vaporization administration represents the timing of the blood draw immediately after the second vaporization session which occurred at 240 minutes.
The recovery period represents blood draw occurred 3 hours later at 420 minutes.
N=18 for the second vaporization administration, N=19 for the recovery period.
N=3 for delta-9-THC for the second vaporization administration. Significant Kruskal–Wallis comparison P-values are in bold; Cur > Ex means that current users had higher levels than ex-users according to Steel–Dwass pairwise comparisons.
Abbreviations: CBD, cannabidiol; CBN, cannabinol; Cur, current users; Ex, ex-users; 11-OH-THC, 11-hydroxy-THC; NA, not analyzed due to all zero values; THC, tetrahydrocannabinol; THC-COOH, 11-nor-9-carboxy-THC; SD, standard deviation.