2 Antidepressants
Compare antidepressant mechanisms and adverse-effect profiles, and review the screening, interaction, monitoring, and treatment-change precautions that guide safe selection.
Mechanisms of action
Antidepressants differ in how they affect neurotransmission. These descriptions are simplified accounts of their actions.
How antidepressant classes differ
Selective serotonin reuptake inhibitors () primarily inhibit serotonin reuptake. Serotonin–norepinephrine reuptake inhibitors () inhibit serotonin and norepinephrine reuptake. primarily inhibits norepinephrine and dopamine reuptake, while monoamine oxidase inhibitors () inhibit monoamine oxidase, an enzyme that breaks down monoamines.
Adverse effects and selection
Adverse-effect profiles can help inform selection, alongside symptoms, medical history, other medicines, prior response, and patient preferences. A tricyclic antidepressant () may cause anticholinergic effects and orthostatic hypotension, and its potential for cardiac toxicity in overdose is an important consideration.
Matching effects to individual needs
commonly causes somnolence and increased appetite or weight. These effects may be relevant for a patient reporting low appetite and difficulty sleeping, but they may be undesirable for others. Selection should account for the individual's symptoms, preferences, and health risks.
Blood-pressure considerations
can increase blood pressure, so blood-pressure monitoring may be appropriate. Monitoring needs should be considered as part of the treatment plan.
and eating-disorder history
is contraindicated for patients with a current or prior diagnosis of bulimia or anorexia nervosa because it increases seizure risk. A patient with this history should disclose it to the prescriber before a treatment is selected.
Bleeding risk and medicine interactions
Serotonin-reuptake inhibitors such as sertraline can increase bleeding risk. Regular NSAID use, warfarin, and other anticoagulants can add to that risk. The care team should review the full medication list and assess appropriate monitoring, including anticoagulation monitoring when indicated.
Avoiding a dangerous combination
Combining serotonergic antidepressants with can cause , a potentially serious interaction. Switching between these drug classes requires clinician direction and an appropriate washout period; the interval depends on the drugs involved.
Dietary precautions with phenelzine
can trigger a hypertensive crisis during phenelzine treatment. Patients should follow the specific dietary guidance provided by their prescriber and pharmacist rather than assuming that all foods pose the same risk.
Screening for
Before starting an antidepressant for depressive symptoms, assess personal or family history of , mania, or hypomania. Antidepressant treatment can precipitate mania or hypomania in some people with , so screening helps guide an appropriate treatment plan.
Monitoring and changing treatment
Close monitoring for worsening mood or suicidal thoughts is especially important early in treatment and after a dose change. New or worsening suicidal thoughts require prompt clinical attention. A patient should not abruptly stop an antidepressant without discussing it with the prescriber; many antidepressants should be tapered to reduce discontinuation symptoms. Treatment changes should be clinician-directed.