Table 1.
Summary of the subclasses of antidepressants
| Drug class | Drugs | Mechanism of action | Adverse effects (general) | Sexual dysfunction |
|---|---|---|---|---|
| Tricyclic antidepressants (TCAs) | Prototypical drug: Imipramine | Inhibits the reuptake of serotonin and norepinephrine | Many; most due to affinity for cholinergic, histaminergic and adrenergic receptors | Approximate prevalence: 30% |
| No longer first-line drugs | Others: amitriptyline, doxepin | Decreased libido, delayed orgasm Men: erectile dysfunction, delayed ejaculation Women: breast enlargement, decreased orgasm |
||
| Selective serotonin reuptake inhibitors (SSRIs) | Prototypical drug: Fluoxetine | Inhibits the reuptake of serotonin | Anticholinergic side effects are not common | Approximate prevalence: 25%–73% |
| First-line drugs | Others: paroxetine, sertraline, fluvoxamine, escitalopram, citalopram | Risk of serotonin syndrome if co-administered with other antidepressants | Decreased libido, delayed/inability to reach orgasm, galactorrhea Men: delayed ejaculation and erectile dysfunction |
|
| Serotonin norepinephrine reuptake inhibitors (SNRIs) | Prototypical drug: Venlafaxine Other: duloxetine |
Inhibits the reuptake of serotonin and norepinephrine | Nausea, nervousness, insomnia | Approximate prevalence: 58%–70% Men: erectile dysfunction, abnormal ejaculation Women: delayed or absent orgasm |
| Monoamine oxidase inhibitors (MAOIs) | Prototypical drug: Phenelzine Also tranylcypromine |
Blocks the enzyme monoamine oxidase which normally inactivates the monoamines: serotonin, dopamine, norepinephrine | Many adverse reactions, eg, hypertensive crisis, so rarely used in clinical practice; due to affinity for cholinergic and adrenergic receptors | Approximate prevalence: 40% Decreased libido, delayed orgasm |
| Norepinephrine and dopamine reuptake inhibitors | Prototypical drug: Bupropion | Inhibits the reuptake of serotonin, norepinephrine and dopamine | Agitation, insomnia, restlessness, weight loss | Approximate prevalence: 10%–25% |
| Norepinephrine reuptake inhibitors | Prototypical drug: Reboxetine | Inhibits the reuptake of norepinephrine | Headache, dry mouth, tachycardia, hypotension, urinary retention, constipation and insomnia | Approximate prevalence: 5%–10% Delayed orgasm, erectile dysfunction may occur rarely |
| Combined reuptake inhibitor and receptor blocker | Trazodone | Inhibits the reuptake of serotonin | Orthostatic hypotension, nausea, sedation, dry mouth | Approximate prevalence: 8%–28% |
| Nefazodone | Inhibits the reuptake of serotonin and blocks serotonin receptors | Liver damage, drowsiness, nausea, vomiting | Ejaculation dysfunctions, anorgasmia, priapism | |
| Mirtazapine | Blocks presynaptic alpha2-adrenergic receptors; also blocks postsynaptic serotonin 5HT2 and 5HT3, histaminergic H1 and alpha1 receptors | Seizures, acute renal failure, hepatitis, leukopenia, orthostatic hypotension | ||
| Mianserin | Blocks presynaptic alpha2 receptors and noradrenaline reuptake | Headache, fatigue, agranulocytosis, anemia | Decreased libido and delayed orgasm possible |
Note: Copyright © 2007. Adapted with permission from Taylor D, Paton C, Kerwin R, editors. The Maudsley Prescribing Guidelines. London, UK: Informa Healthcare; 2007.