Occupancies of brain dopamine receptors by antipsychotic drugs
| Drug | Percent Occupancy | Drug Concentration | ||
|---|---|---|---|---|
| D2 | D3 | D4 | ||
| nM | ||||
| Chlorpromazine | 78 | 62 | 17 | 1.95 |
| Clozapine | 38–63 | 21–42 | 49–73 | 21.5–59.6 |
| Haloperidol | 85 | 52 | 57 | 3.0 |
| Olanzapine | 43–89 | 10–55 | 27–80 | 5.6–60.7 |
| Quetiapine | 51 | 24 | 88 | 109 |
| Raclopride | 80 | 69 | 0.2 | 4 |
| Risperidone | 63–89 | 25–61 | 22–55 | 2.2–10.5 |
| Sulpiride | 78 | 53 | 1 | 8.9 |
Receptor occupancies for the D2 receptor in the striatum were taken from PET scan data in Farde et al (1992),Nordstrom et al. (1995), Hagberg et al. (1998), and Kapur et al. (1999), and were used to calculate concentration of the drug in the brain using the dissociation constants from Table 1. Drug concentration was then used to calculate the percent occupancy of D3 and D4receptors using their dissociation constants in Table 1.