| Class | H1 receptor antagonist | Dopamine receptor antagonist |
|---|---|---|
| Chemistry |
Piperazine derivative |
Piperazine derivative
|
| Routes of administration |
Oral, IV, IM, s/c |
Oral, IV, IM, s/c |
| Absorption |
Rapidly and completely absorbed, bioavailability ~50-80% |
Rapidly and completely absorbed, bioavailability ~50-80%
|
| Solubility |
pKa 8.5, water soluble |
pKa 8.5, water soluble
|
| Distribution |
VOD = 16-20 L/kg, 59-76% protein-bound |
VOD = 16-20 L/kg, 59-76% protein-bound
|
| Metabolism |
Undergoes extensive hepatic metabolism, mainly by CYP 2D6 |
Undergoes extensive hepatic metabolism, mainly by CYP 2D6
|
| Elimination |
Clearance is almost completely hepatic; only some minimal amount is eliminated by the kidneys |
Clearance is almost completely hepatic; only some minimal amount is eliminated by the kidneys
|
| Time course of action |
Half-life of 20 hours; duration of effect is 4-6 hours |
Half-life of 20 hours; duration of effect is 4-6 hours
|
| Target receptor |
H1 histamine receptors (Gq-protein coupled); also has antimuscarinic effects |
H1 histamine receptors (Gq-protein coupled); also has antimuscarinic effects |
| Mechanism of action |
Central antinausea/antiemetic effects are mediated by both the antimuscarinic effects and the antihistamine effects. The worst of the adverse effects are predominantly due to the antimuscarinic properties. |
Central antinausea/antiemetic effects are mediated by both the antimuscarinic effects and the antihistamine effects. The worst of the adverse effects are predominantly due to the antimuscarinic properties. |
| Clinical effects |
#NAME? |
- Sedation |
| Literature reference |
TGA document |
|
| CICM details of understanding | Level 3 | Level 3 |
| Mentioned around Deranged Physiology | ||
| Related SAQs |
|