| Class | Decongestant |
|---|---|
| Chemistry |
Imidazoline derivative |
| Routes of administration |
intranasal |
| Absorption |
Almost 100% bioavailability |
| Solubility |
pKa = 10.15, good water solubility |
| Distribution |
VOD= 19L/kg, 56% protein-bound |
| Metabolism |
Minimally metabolised |
| Elimination |
Mostly eliminated renally |
| Time course of action |
Half-life is 5 hours |
| Target receptor |
Alpha-1 and alpha-2 noradrenaline receptors |
| Mechanism of action |
Imidazoline-derived alpha agonists have a direct vasoconstrictor effect via alpha-1 receptors, and an indirect sympatholytic effect via alpha-2 agonism which is only observed in overdose, when these agents cross the blood brain barrier |
| Clinical effects |
Increased peripheral resistance, increased afterload, increased blood pressure; redistribution of blood flow from splanchnic circulation and skeletal muscle. Sedation, bradycardia and hypotension in overdose |
| Literature reference |
Khan et al, 1999 |
| CICM details of understanding | Not specifically listed in the CICM syllabus |
| Mentioned around Deranged Physiology | |
| Related SAQs |