Target occupancy studies
Studies have estimated occupancy of target sites by trazodone based on trazodone concentrations in blood and brain and on the affinities of trazodone for the human targets in question. Roughly half of brain 5-HT2A receptors are blocked by 1 mg of trazodone and essentially all 5-HT2A receptors are saturated at 10 mg of trazodone, but the clinically effective hypnotic doses of trazodone are in the 25–100 mg range. The occupancy of the serotonin transporter (SERT) by trazodone is estimated to be 86% at 100 mg/day and 90% at 150 mg/day. Trazodone may almost completely occupy the 5-HT2A and 5-HT2C receptors at doses of 100 to 150 mg/day. Significant occupancy of a number of other sites may also occur. However, another study estimated much lower occupancy of the SERT and 5-HT2A receptors by trazodone. Correspondence to clinical effects
Trazodone may act predominantly as a 5-HT2A receptor antagonist to mediate its therapeutic benefits against anxiety and depression. Its inhibitory effects on serotonin reuptake and 5-HT2C receptors are comparatively weak. In relation to these properties, trazodone does not have similar properties to selective serotonin reuptake inhibitors (SSRIs) and is not particularly associated with increased appetite and weight gain—unlike other 5-HT2C antagonists like mirtazapine. Moderate 5-HT1A partial agonism may contribute to trazodones antidepressant and anxiolytic actions to some extent as well.The combined actions of 5-HT2A and 5HT2C receptor antagonism with serotonin reuptake inhibition only occur at moderate to high doses of trazodone.
Anti-vascular endothelial growth factors have been recently used for the treatment of radiation retinopathy. Monitoring of visual acuity in all cases and early referral to the ophthalmologist is warranted. == References ==