Prochlorperazine is a dopamine D2 receptor antagonist with Ki values of 4.7 and 2.9 nM for rat recombinant D2 receptors in CHO cells and rat striatal membranes, respectively. It also binds to rat recombinant D3 receptors expressed in CHO cells (Ki = 35 nM) and to the serotonin (5-HT) receptor subtype 5-HT3 in N1E-115 mouse neuroblastoma cell membranes (Ki = 1,200 nM). Prochlorperazine (2 mg/kg) increases the latency to paw licking in a hot plate test, indicating analgesia, an effect that is blocked by antisense oligonucleotides against the M1 muscarinic receptor. It also inhibits emesis induced by apomorphine in dogs (ED50 = 0.34 mg/kg). Formulations containing prochlorperazine have been used in the treatment of psychotic disorders and as antiemetics.