Two medicines, side by side

Mirtazapine vs desvenlafaxine

Mirtazapine and desvenlafaxine are both labeled for depression. Drugs@FDA records approvals of mirtazapine since 1996 and of desvenlafaxine since 2008. Pharmacies paid $0.063 per mirtazapine 15 mg tablet and $0.396 per unit (Desvenlafaxine succnt ER 50 mg) (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like.

Check it at the source: the mirtazapine FDA label on DailyMed (effective August 6, 2025); the desvenlafaxine FDA label on DailyMed (effective January 27, 2023).

Highlights of the mirtazapine record

Mirtazapine (Remeron) · label of August 6, 2025

Boxed warning

SUICIDAL THOUGHTS AND BEHAVIORS Antidepressants increased the risk of suicidal thoughts and behaviors in pediatric and young adult patients in short-term studies. Closely monitor all antidepressant-treated patients for clinical worsening, and for emergence of suicidal thoughts and behaviors [see Warnings and Precautions (5.1) ]. REMERON/REMERONSolTab is not approved for use in pediatric patients [see Use in Specific Populations (8.4) ].

Used for

From the label: indications
REMERON/REMERONSolTab are indicated for the treatment of major depressive disorder (MDD) in adults [see Clinical Studies (14) ]. REMERON/REMERONSolTab is indicated for the treatment of major depressive disorder (MDD) in adults.

On the market

Earliest approval on file: June 14, 1996
Generic labelers: 36 labelers
Pharmacy cost: $0.063 per tablet

Supply and safety

Shortage: No current entry
Recalls: 5

Highlights of the desvenlafaxine record

Desvenlafaxine (Pristiq) · label of January 27, 2023

Boxed warning

SUICIDAL THOUGHTS AND BEHAVIORS Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term studies. These studies did not show an increase in the risk of suicidal thoughts and behavior with antidepressant use in patients over age 24; there was a reduction in risk with antidepressant use in patients aged 65 and older [see Warnings and Precautions (5.1)].

Used for

From the label: indications
Desvenlafaxine, a serotonin and norepinephrine reuptake inhibitor (SNRI), is indicated for the treatment of major depressive disorder (MDD) [see Clinical Studies (14) and Dosage and Administration (2.1)]. The efficacy of desvenlafaxine has been established in four short-term (8-week, placebo-controlled studies) of outpatients who met DSM-IV criteria for major depressive disorder. […]

On the market

Earliest approval on file: February 29, 2008
Generic labelers: 20 labelers
Pharmacy cost: $0.396 per unit

Supply and safety

Shortage: No current entry
Recalls: 2

Source: FDA drug labels via openFDA (Mirtazapine label of August 6, 2025, Desvenlafaxine label of January 27, 2023); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)

How do mirtazapine and desvenlafaxine differ on the record?

How each works, in its label's words: Mirtazapine, “The mechanism of action of mirtazapine for the treatment of major depressive disorder, is unclear.”; Desvenlafaxine, “The exact mechanism of the antidepressant action of desvenlafaxine is unknown, but is thought to be related to the potentiation of serotonin and norepinephrine in the central nervous system, through …”

Half-life, in each label's words: Mirtazapine, “Elimination Mirtazapine has a half-life of about 20 to 40 hours following oral administration of REMERON or …”; Desvenlafaxine, “The mean terminal half-life (t 1/2 ) was prolonged from 11.1 hours in the control subjects to approximately 13.5, 15.5 …”

Both labels carry a boxed warning; the records quote them.

Generics: mirtazapine since 2003; desvenlafaxine since 2015 (Drugs@FDA).

	Mirtazapine	Desvenlafaxine
Labeled for	Depression	Depression
Pharmacologic class	n/a	Serotonin and Norepinephrine Reuptake Inhibitor
How it works (label)	The mechanism of action of mirtazapine for the treatment of major depressive disorder, is unclear.	The exact mechanism of the antidepressant action of desvenlafaxine is unknown, but is thought to be related to the potentiation of serotonin and norepinephrine in the central nervous system, through inhibition of their reuptake.
Half-life (label)	Elimination Mirtazapine has a half-life of about 20 to 40 hours following oral administration of REMERON or REMERONSolTab.	The mean terminal half-life (t 1/2 ) was prolonged from 11.1 hours in the control subjects to approximately 13.5, 15.5, 17.6, and 22.8 hours in mild, moderate, severe renal impairment and ESRD subjects, respectively.
Earliest approval on file (Drugs@FDA)	June 14, 1996	February 29, 2008
First generic approved	January 24, 2003	June 29, 2015
Generic labelers (NDC)	36 labelers	20 labelers
Pharmacy cost (NADAC, each one's most listed form; strengths differ)	$0.063 per tablet (Mirtazapine 15 mg tablet)	$0.396 per unit (Desvenlafaxine succnt ER 50 mg)
12-month price change	-12%	-6%
Boxed warning	Yes	Yes
Shortage now	No current entry	No current entry
Recalls recorded	5	2
FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used)	91,057	26,842
DEA schedule	none	none

Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)

What do the labels say about using others of their kind?

Mirtazapine label, warnings and precautions
Increased risk when co-administered with other serotonergic drugs (e.g., SSRI, SNRI, triptans), but also when taken alone.

Desvenlafaxine label, warnings and precautions
Serotonin syndrome has been reported with SSRIs and SNRIs, including with desvenlafaxine extended-release tablets, both when taken alone, but especially when co-administered with other serotonergic agents (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, amphetamines, and St. John's Wort).

Source: FDA drug labels via openFDA

What next?

Mirtazapine: the full record
Desvenlafaxine: the full record
Alternatives to mirtazapine: every medicine labeled for the same conditions