Mirtazapine

Mirtazapine
Clinical data
Trade names	Remeron, others
Other names	Mepirzapine; 6-Azamianserin; ORG-3770
AHFS/Drugs.com	Monograph
MedlinePlus	a697009
License data	US DailyMed: Mirtazapine;
Pregnancy; category	AU: B3;
Routes of; administration	By mouth, topical
Drug class	Noradrenergic and specific serotonergic antidepressant (NaSSA)
ATC code	N06AX11 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); BR: Class C1 (Other controlled substances); CA: ℞-only; UK: POM (Prescription only); US: ℞-only; EU: Rx-only;
Pharmacokinetic data
Bioavailability	50%
Protein binding	85%
Metabolism	Liver (CYP1A2, CYP2D6, CYP3A4)
Metabolites	Desmethylmirtazapine (contributes 3–10% of activity)
Elimination half-life	20–40 hours
Excretion	Urine: 75%; Feces: 15%
Identifiers
	IUPAC name (±)-5-methyl-2,5,19-triazatetracyclo[13.4.0.02,7.08,13]nonadeca-1(15),8,10,12,16,18-hexaene;
CAS Number	85650-52-8 ;
PubChem CID	4205;
IUPHAR/BPS	7241;
DrugBank	DB00370 ;
ChemSpider	4060 ;
UNII	A051Q2099Q;
KEGG	D00563 ;
ChEBI	CHEBI:6950 ;
ChEMBL	ChEMBL654 ;
CompTox Dashboard (EPA)	DTXSID0023325 ;
ECHA InfoCard	100.080.027
Chemical and physical data
Formula	C17H19N3
Molar mass	265.360 g·mol−1
3D model (JSmol)	Interactive image;
Chirality	Racemic mixture
Density	1.22 g/cm3
Melting point	114 to 116 °C (237 to 241 °F)
Boiling point	432 °C (810 °F)
Solubility in water	Soluble in methanol and chloroform mg/mL (20 °C)
	SMILES n1cccc3c1N4C(c2ccccc2C3)CN(C)CC4;
	InChI InChI=1S/C17H19N3/c1-19-9-10-20-16(12-19)15-7-3-2-5-13(15)11-14-6-4-8-18-17(14)20/h2-8,16H,9-12H2,1H3 ; Key:RONZAEMNMFQXRA-UHFFFAOYSA-N ;
	(verify)

Mirtazapine, sold under the brand name Remeron among others, is an atypical tetracyclic antidepressant, and as such is used primarily to treat depression. Its effects may take up to four weeks but can also manifest as early as one to two weeks. It is often used in cases of depression complicated by anxiety or insomnia. The effectiveness of mirtazapine is comparable to other commonly prescribed antidepressants. It is taken by mouth.

Common side effects include sleepiness, dizziness, increased appetite, and weight gain. Serious side effects may include mania, low white blood cell count, and increased suicide among children. Withdrawal symptoms may occur with stopping. It is not recommended together with a monoamine oxidase inhibitor, although evidence supporting the danger of this combination has been challenged. It is unclear if use during pregnancy is safe. How it works is not clear, but it may involve blocking certain adrenergic and serotonin receptors. Chemically, it is a tetracyclic antidepressant, and is closely related to mianserin. It also has strong antihistaminergic effects.

Mirtazapine came into medical use in the United States in 1996. The patent expired in 2004, and generic versions are available. In 2022, it was the 105th most commonly prescribed medication in the United States, with more than 6 million prescriptions.