Table 2.

Combination of drugs known to cause excessive serotonin

Drug group/drug	SSRIs	SNRIs	MAOIs	TCAs	Opiates	Triptans	Combinations with excessive evidence
SSRIs	✓	✓	✓	✓	✓	✓	Most SSRIs with L-tryptophan Fluoxetine with carbamazepine, fentanyl, phentermine
SNRIs	✓		✓	✓	✓	✓	Venlafaxine alone or in combination with amitriptyline, calcineurin inhibitors, fluoxetine, lithium, meperidine, methadone, mirtazapine, quetiapine, sertraline, tramadol, tranylcypromine, trazodone
MAOI	✓	✓	✓	✓	✓	-	Phenelzine with meperidine Tranylcypromine with imipramine Methylene blue with paroxetine, clomipramine
TCAs	✓	✓	✓	-	-	-	-
Opiates	✓	✓	✓	-	-	✓	Tramadol alone or with mirtazapine, olanzapine
Dextromethorphan	✓	-	-	-	-	-	Amitriptyline Chlorpheniramine Risperidone
Buspirone	✓	-	-	-	-	-	-
Mirtazapine	✓	-	-	-	-	-	-
Linezolid	✓	-	-	-	-		Tapentadol
Olanzapine	-	-	-	-	-		Lithium Citalopram
Trazodone	-	-	-	-	-		Amitriptyline Lithium
Risperidone	-	-	-	-	-		Dextromethorphan Fluoxetine Paroxetine
Ciprofloxacin	-	-	-	-	-		Venlafaxine, methadone
Fluconazole	-	-	-	-	-		Citalopram

Tick mark means that the group on left side in combination with group/drug on column title may cause Serotonin Syndrome. SSRIs=Selective serotonin reuptake inhibitors, SNRIs=Serotonin–norepinephrine reuptake inhibitors, MAOI=Monoamine oxidase inhibitors, TCAs=Tricyclic antidepressants