15.3 : 抗うつ薬: 三環系抗うつ薬、SSRI、SNRI

Tricyclic antidepressants, or TCAs, are first-generation antidepressants.

They block serotonin and norepinephrine reuptake transporters while inhibiting muscarinic, α-adrenergic, and histaminic H₁ receptors.

TCAs are not first-line antidepressants due to their nonselective nature and larger side effect profile, though they help mitigate pain syndromes and insomnia.

Serotonin-norepinephrine reuptake inhibitors, or SNRIs, also inhibit serotonin and norepinephrine reuptake.

These agents can cause noradrenergic stimulation-related adverse effects such as hypertension, tachycardia, insomnia, anxiety, and agitation.

Selective serotonin reuptake inhibitors, or SSRIs, predominantly block serotonin reuptake without significantly affecting norepinephrine.

SSRIs are mainly used to treat obsessive-compulsive disorders, panic, and social anxiety disorders.

However, they can cause side effects like headaches, sweating, gastrointestinal effects, and sexual dysfunction. In combination with other serotonergic drugs, SSRIs may cause rare side effects like serotonin syndrome and seizures.

They should be used cautiously in young patients as they may worsen depression and induce suicidal tendencies.