| Class | SSRI/SNRI |
|---|---|
| Chemistry |
Phenoxyphenylpropylamine
|
| Routes of administration |
Oral only |
| Absorption |
Acid-labile; degraded by stomach acid (thus, requires enteric-coated tablets). Bioavailability is 50%
|
| Solubility |
pKa 9.34; very poor water solubility
|
| Distribution |
VOD=25L/kg; 90% protein bound
|
| Metabolism |
Hepatic metabolism into numerous metabolites, mainly by oxidation in the naphthyl ring followed by further oxidation, methylation and conjugation
|
| Elimination |
Elimination of inactive metabolites is mainly renal
|
| Time course of action |
Half life is about 12 hours
|
| Target receptor |
Serotonin reuptake transport protein (SCL6A4, or SERT), as well as noradrenaline reuptake transporter (NET). |
| Mechanism of action |
By inhibiting the reuptake of serotonin and noradrenaline from the synaptic cleft, SSRI/SNRI drugs increase monoamine neurotransmission, which is thought to be involved in mood regulation. |
| Clinical effects |
Agitation, diarrhoea, loss or gain of weight, vertigo; risk of serotonin syndrome with overdose (i.e. similar side effect profile to SSRIs). Additionally, duloxetine can sometimes have anticholinergic side effects, such as xerostomia and urinary retention |
| Literature reference |
Knadler et al (2011) |
| CICM details of understanding | Not specifically listed in the CICM syllabus |
| Mentioned around Deranged Physiology | |
| Related SAQs |