<P> Atypical antipsychotics are most commonly administered orally . Antipsychotics can also be injected, but this method is not as common . They are lipid - soluble, are readily absorbed from the digestive tract, and can easily pass the blood--brain barrier and placental barriers . Once in the brain, the antipsychotics work at the synapse by binding to the receptor . Antipsychotics are completely metabolized in the body and the metabolites are excreted in urine . These drugs have relatively long half - lives . Each drug has a different half - life, but the occupancy of the D2 receptor falls off within 24 hours with atypical antipsychotics, while lasting over 24 hours for the typical antipsychotics . This may explain why relapse into psychosis happens quicker with atypical antipsychotics than with typical antipsychotics, as the drug is excreted faster and is no longer working in the brain . Physical dependence with these drugs is very rare . However, if the drug is abruptly discontinued, psychotic symptoms, movement disorders, and sleep difficulty may be observed . It is possible that withdrawal is rarely seen because the AAP are stored in body fat tissues and slowly released . </P> <Table> <Tr> <Th_colspan="10"> (show) Pharmacokinetic parameters of available atypical antipsychotics </Th> </Tr> <Tr> <Th> Drug </Th> <Th> Route (s) of Administration </Th> <Th> Half - life (t in hours) </Th> <Th> Volume of distribution (V in L / kg) </Th> <Th> Protein binding </Th> <Th> Excretion </Th> <Th> Enzymes involved in metabolism </Th> <Th> Bioavailability </Th> <Th> Peak plasma time (h) </Th> <Th> C (ng / mL) </Th> </Tr> <Tr> <Td> Amisulpride </Td> <Td> Oral </Td> <Td> 12 </Td> <Td> 5.8 </Td> <Td> 16% </Td> <Td> Urine (50%), faeces (20%; 70% of this is as unchanged drug) </Td> <Td>? </Td> <Td> 48% </Td> <Td> Two peaks: 1 hr & 3 - 4 hrs post-oral dosing </Td> <Td> 39 ± 3 (1 hr), 54 ± 4 (3 - 4 hrs) </Td> </Tr> <Tr> <Td> Aripiprazole </Td> <Td> Oral, intramuscular (including depot) </Td> <Td> 75 (94 for active metabolite) </Td> <Td> 4.9 </Td> <Td> 99% </Td> <Td> Faeces (55%), urine (25%) </Td> <Td> CYP2D6 & CYP3A4 </Td> <Td> 87% (Oral), 100% (IM) </Td> <Td> 3 - 5 </Td> <Td>? </Td> </Tr> <Tr> <Td> Asenapine </Td> <Td> Sublingual </Td> <Td> 24 </Td> <Td> 20 - 25 </Td> <Td> 95% </Td> <Td> Urine (50%), faeces (40%) </Td> <Td> CYP1A2 & UGT1A4 </Td> <Td> 35% (sublingual), <2% (Oral) </Td> <Td> 0.5 - 1.5 </Td> <Td> </Td> </Tr> <Tr> <Td> Blonanserin </Td> <Td> Oral </Td> <Td> 10.7 (single 4 mg dose), 12 (single 8 mg dose), 16.2 (single 12 mg dose), 67.9 (repeated bid dosing) </Td> <Td>? </Td> <Td>> 99.7% </Td> <Td> Urine (59%), faeces (30%) </Td> <Td> CYP3A4 </Td> <Td> 84% (Oral) </Td> <Td> <2 </Td> <Td> 0.14 (single 4 mg dose), 0.45 (single 8 mg dose), 0.76 (single 12 mg dose), 0.57 (bid dosing) </Td> </Tr> <Tr> <Td> Clozapine </Td> <Td> Oral </Td> <Td> 8 hours (single dosing), 12 (twice daily dosing) </Td> <Td> 4.67 </Td> <Td> 97% </Td> <Td> Urine (50%), faeces (30%) </Td> <Td> CYP1A2, CYP3A4, CYP2D6 </Td> <Td> 50 - 60% </Td> <Td> 1.5 - 2.5 </Td> <Td> 102 - 771 </Td> </Tr> <Tr> <Td> Iloperidone </Td> <Td> Oral </Td> <Td>? </Td> <Td> 1340 - 2800 </Td> <Td> 95% </Td> <Td> Urine (45 - 58%), faeces (20 - 22%) </Td> <Td> CYP2D6 & CYP3A4 </Td> <Td> 96% </Td> <Td> 2 - 4 </Td> <Td>? </Td> </Tr> <Tr> <Td> Lurasidone </Td> <Td> Oral </Td> <Td> 18 </Td> <Td> 6173 </Td> <Td> 99% </Td> <Td> Faeces (80%), urine (9%) </Td> <Td> CYP3A4 </Td> <Td> 9 - 19% </Td> <Td> 1 - 3 </Td> <Td>? </Td> </Tr> <Tr> <Td> Melperone </Td> <Td> Oral, intramuscular </Td> <Td> 3 - 4 (Oral), 6 (IM) </Td> <Td> 7 - 9.9 </Td> <Td> 50% </Td> <Td> Urine (70% as metabolites; 5 - 10.4% unchanged drug) </Td> <Td>? </Td> <Td> 65% (tablet), 87% (IM), 54% (oral syrup) </Td> <Td> 0.5 - 3 </Td> <Td> 75 - 324 (repeated dosing) </Td> </Tr> <Tr> <Td> Olanzapine </Td> <Td> Oral, intramuscular (including depot) </Td> <Td> 30 </Td> <Td> 1000 </Td> <Td> 93% </Td> <Td> Urine (57%), faeces (30%) </Td> <Td> CYP1A2, CYP2D6 </Td> <Td>> 60% </Td> <Td> 6 (Oral) </Td> <Td>? </Td> </Tr> <Tr> <Td> Paliperidone </Td> <Td> Oral, intramuscular (including depot) </Td> <Td> 23 (Oral) </Td> <Td> 390 - 487 </Td> <Td> 74% </Td> <Td> Urine (80%), faeces (11%) </Td> <Td> CYP2D6, CYP3A4 </Td> <Td> 28% </Td> <Td> 24 (Oral) </Td> <Td>? </Td> </Tr> <Tr> <Td> Perospirone </Td> <Td> Oral </Td> <Td>? </Td> <Td>? </Td> <Td> 92% </Td> <Td> Urine (0.4% as unchanged drug) </Td> <Td>? </Td> <Td>? </Td> <Td> 1.5 </Td> <Td> 1.9 - 5.7 </Td> </Tr> <Tr> <Td> Quetiapine </Td> <Td> Oral </Td> <Td> 6 (IR), 7 (XR) </Td> <Td> 6 - 14 </Td> <Td> 83% </Td> <Td> Urine (73%), faeces (20%) </Td> <Td> CYP3A4 </Td> <Td> 100% </Td> <Td> 1.5 (IR), 6 (XR) </Td> <Td>? </Td> </Tr> <Tr> <Td> Risperidone </Td> <Td> Oral, intramuscular (including depot) </Td> <Td> 3 (EM) (oral), 20 (PM) (oral) </Td> <Td> 1 - 2 </Td> <Td> 90%, 77% (metabolite) </Td> <Td> Urine (70%), faeces (14%) </Td> <Td> CYP2D6 </Td> <Td> 70% </Td> <Td> 3 (EM), 17 (PM) </Td> <Td>? </Td> </Tr> <Tr> <Td> Sertindole </Td> <Td> Oral </Td> <Td> 72 (55 - 90) </Td> <Td> 20 </Td> <Td> 99.5% </Td> <Td> Urine (4%), faeces (46 - 56%) </Td> <Td> CYP2D6 </Td> <Td> 74% </Td> <Td> 10 </Td> <Td>? </Td> </Tr> <Tr> <Td> Ziprasidone </Td> <Td> Oral, intramuscular </Td> <Td> 7 (oral) </Td> <Td> 1.5 </Td> <Td> 99% </Td> <Td> Faeces (66%), urine (20%) </Td> <Td> CYP3A4 & CYP1A2 </Td> <Td> 60% (Oral), 100% (IM) </Td> <Td> 6 - 8 </Td> <Td>? </Td> </Tr> <Tr> <Td> Zotepine </Td> <Td> Oral </Td> <Td> 13.7 - 15.9 </Td> <Td> 10 - 109 </Td> <Td> 97% </Td> <Td> Urine (17%) </Td> <Td>? </Td> <Td> 7 - 13% </Td> <Td>? </Td> <Td>? </Td> </Tr> <Tr> <Td_colspan="10"> <P> Acronyms used: IR - Immediate release formulation . XR - Extended release formulation . EM - Extensive metabolisers . PM - Poor metabolisers . C - maximum plasma concentrations of the drug . </P> </Td> </Tr> </Table> <Tr> <Th_colspan="10"> (show) Pharmacokinetic parameters of available atypical antipsychotics </Th> </Tr> <Tr> <Th> Drug </Th> <Th> Route (s) of Administration </Th> <Th> Half - life (t in hours) </Th> <Th> Volume of distribution (V in L / kg) </Th> <Th> Protein binding </Th> <Th> Excretion </Th> <Th> Enzymes involved in metabolism </Th> <Th> Bioavailability </Th> <Th> Peak plasma time (h) </Th> <Th> C (ng / mL) </Th> </Tr>

What are the primary differences between typical and atypical antipsychotics