Antidepressants main properties

In CONCLUSION it appears that the chemically and pharmacologically diverse drugs that act as antidepressants have two properties in common. Firstly, they demonstrate approximately equal clinical efficacy and require several weeks administration to produce an optimal therapeutic effect. Secondly, they all modulate a number of different t)rpes of mainly postsynaptic neurotransmitter receptors in animals and in depressed... 

One of the main side-effects of opioid analgesics, such as codeine and tramadol, is constipation. Amitriptyline (tricyclic antidepressant) and orphenadrine tend to have antimuscarinic properties, resulting in side-effects such as constipation. Senna is a stimulant laxative indicated in constipation. 

Both mianserin and mirtazapine are antidepressant drugs which possess central 0C2 adrenoceptor blocking properties (pA2 7.3). However, mirtazapine is much more potent at histamine Hi receptors (pA2 9.1) and at 5-HT2 and 5-HT3 receptors (pA2 8.2). Blocking of Hi receptors explains the main side effects of mirtazapine, which produces marked sedation and weight gain. Blockade of presynaptic inhibitory 0C2 autoreceptors increases the release of NA, while blockade of presynaptic 0C2 inhibitory heteroreceptors on serotonin nerve terminals (Table 2) is likely to increase the release of serotonin. 

Of the more recently introduced methods for smoking cessation, bupropion (an antidepressant with dopaminomimetic properties) has recently been introduced. Clinical trial data, in which the nicotine patch, bupropion at 300 mg, and a combination of the two drugs were compared with placebo treatment, have shown cessation of smoking rates of 36% for the patch, 49% for bupropion and 58% for the combined treatments following 7 weeks of treatment. The placebo response rate was 23%. All subjects received relapse prevention therapy. Thus bupropion appears to be a reasonably safe and effective treatment for nicotine dependence. It is however contraindicated in those subject to epilepsy its main side effects are dry mouth and insomnia. 

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