| Mechanism | Drugs involved |
| Increases serotonin formation | Tryptophan |
| Increases release of serotonin | Amphetamines (including dextroamphetamine, methamphetamine) |
| Cocaine | |
| MDMA (Ecstasy) | |
| Amphetamine derivatives (including fenfluramine, dexfenfluramine, phentermine) | |
| Levodopa, carbidopa-levodopa (indirectly causes release serotonin) | |
| Impairs reuptake from the synaptic cleft into the presynaptic neuron | Cocaine |
| MDMA (Ecstasy) | |
| Meperidine | |
| Tramadol | |
| Pentazocine | |
| Selective serotonin reuptake inhibitors (SSRIs; including citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline) | |
| Serotonin-norepinephrine reuptake inhibitors (SNRIs; including desvenlafaxine, duloxetine, milnacipran, and venlafaxine) | |
| Dopamine-norepinephrine reuptake inhibitors (including bupropion) | |
| Serotonin modulators (including nefazodone, trazodone, and vilazodone) | |
| Tricyclic antidepressants (TCAs; including amitriptyline, amoxapine, clomipramine, desipramine, doxepin, imipramine, maprotiline, nortriptyline, protriptyline, trimipramine) | |
| St. John's wort (Hypericum perforatum) | |
| 5-HT3 receptor antagonists (including dolasetron, granisetron, ondansetron, palonosetron) | |
| Metoclopramide | |
| Valproate | |
| Carbamazepine | |
| Sibutramine | |
| Dextromethorphan | |
| Cyclobenzaprine | |
| Inhibits serotonin metabolism (ie, inhibits monoamine oxidase activity) | Monoamine oxidase inhibitors (MAOIs; including phenelzine, tranylcypromine, isocarboxazid, moclobemide, safinamide, selegiline, rasagiline, linezolid, tedizolid, methylene blue, procarbazine, Syrian rue [Peganum harmala, harmine]) |
| Direct serotonin agonist | Buspirone |
| Triptans (including sumatriptan, rizatriptan, others) | |
| Ergot derivatives (including ergotamine, methylergonovine) | |
| Fentanyl | |
| Lysergic acid diethylamide (LSD) | |
| Increases sensitivity of postsynaptic receptor | Lithium |