Mirtazapine inhibits presynaptic serotonin (5-HT)-2 and alpha-2 adrenergic auto- and hetero-receptors, thereby increasing serotonergic and noradrenergic neurotransmission. The increased amount of 5-HT released interacts with postsynaptic 5-HT1 receptors, which may be relevant to the antidepressant effects of the drug. The affinity of mirtazapine for central alpha-2 adrenoreceptors is 10 times higher than for peripheral receptors, resulting in fewer peripheral effects related to increased blood pressure. Mirtazapine is an antagonist at postsynaptic 5-HT2A, 5-HT2C, and 5-HT3 receptors. The blockade of these receptors may result in a lower incidence of certain adverse effects (e.g., anxiety, insomnia, nausea) than occurs with antidepressants that do not antagonize these receptors. Mirtazapine significantly antagonizes histamine H1 receptors at low doses, and this activity is associated with sedation and appetite stimulation. Higher doses have a greater effect on norepinephrine release relative to antihistamine effects, which may offset the sedative potential and appetite stimulation observed at low doses. Mirtazapine has muscarinic antagonist properties, which may be associated with xerostomia, constipation, and other anticholinergic effects. Orthostatic hypotension is the result of the peripheral alpha-1 adrenergic antagonism of the drug. Mirtazapine does not have clinically significant receptor affinity for dopamine, 5-HT1A, or 5-HT1B, and has no effects on the central reuptake of either norepinephrine or serotonin.:
- 5-HT2A receptor
- 5-HT2C receptor
- α2A-adrenergic receptor
- α2B-adrenergic receptor
- α2C-adrenergic receptor
- mACH receptors
Mirtazapine has also been found to modulate the κ3 opioid receptor, supporting the claim that mirtazapine causes pain relief and adds to the sedative and hallucinogenic effects of mirtazapine. This even may explain mirtazapine's withdrawal/discontinuation effects as well as its promotion of diuresis and a possible increase in food intake (usually resulting in weight gain).
It should be noted that although some of these effects are observed in those who take mirtazapine recreationally (or one off dosing) most neurophysiological effects are observed in those with on-going use (15, 30 and 45 mg daily prescribed for depression, etc) due to a maintained level of mirtazapine in the body.
The oral bioavailability of mirtazapine is about 50%. It is found mostly bound to plasma proteins, about 85%. It is metabolized primarily in the liver by demethylation and hydroxylation via cytochrome P450 enzymes, CYP1A2, CYP2D6, CYP3A4. and about 15% is eliminated in feces.
Although mirtazapine exhibits almost exclusively psychedelic effects, the hallucinations that accompany it do have distinctively deliriant-like effects. For example, they are often delirious in their believability and rarely comprised of condensed visual geometry. Instead they tend to be solid and extremely realistic in appearance.
The mental processes, thought patterns and general head space experienced during a high dose mirtazapine experience is one that is typically described to be completely devoid of insight. In contrast to many other substances with hallucinogenic properties, it produces no introspection, personal problem solving or creativity enhancing effects; for this reason it is generally reported that mirtazapine holds no therapeutic potential when used as a hallucinogen.
- Combination effects
- Cannabis** - When mirtazapine is combined with cannabis, the euphoric and visual effects are greatly potentiated.
- Psychedelics** - Due to mirtazapines action as a 5-HT2A antagonist, it can help reduce the intensity or "abort" a bad trip
Mirtazapine is not known to cause brain damage, and has extremely low toxicity relative to dose. Similar to other psychedelic drugs, there are relatively few physical side effects associated with mirtazapine exposure. Various studies have shown that in reasonable doses in a careful context, it presents no negative cognitive, psychiatric or toxic physical consequences of any sort.
-not habit-forming when used as a hallucinogen and the desire to use it can actually decrease with use. It is most often self-regulating.almost immediately after ingestion. After that,37 days to be back at baseline (in the absence of further consumption).
Mirtazapine is considered to be relatively safe in the event of an overdose, although it is considered slightly more toxic in overdose than most of the SSRIs (except citalopram). Unlike the TCAs, mirtazapine showed no significant cardiovascular adverse effects at 7 to 22 times the maximum recommended dose. Case reports of overdose with as much as 30 to 50 times the standard dose described the drug as relatively nontoxic, compared to TCAs.
Twelve reported fatalities have been attributed to mirtazapine overdose. The fatal toxicity index (deaths per million prescriptions) for mirtazapine is 3.1 (95% CI: 0.1 to 17.2). This is similar to that observed with SSRIs.
It is strongly recommended that one use harm reduction practices when using this substance.
-Antidepressants** - Different types of antidepressants can cause adverse effects as well as possible serotonin syndrome when mixed.
Mirtazapine is legally approved for medical purposes worldwide. However, it is illegal to sell and possess in most countries without a prescription.
Switzerland: Mirtazapine is listed as a "Abgabekategorie B" pharmaceutical, which generally requires a prescription.
Turkey: Mirtazapine is classed as anti-depressant so it is prescription only drug but the law is often unenforced.
United Kingdom:** Mirtazapine is a licensed prescription-only medicine (POM) in the United Kingdom. It is not a criminal offence to possess this medicine without a valid prescription. This medicine can legally be obtained with a valid prescription or through legal import of the medicine for personal use as outlined in Section 13 of the Medicines Act 1968.
United States:** Mirtazapine is not a controlled substance in the United States; however, it is classified as RX only and requires a prescription.
Responsible use
Hallucinogen
Psychedelic
Deliriant
Mirtazapine (Wikipedia)
Mirtazapine (Erowid Vault)
Mirtazapine (Isomer Design)
Mirtazapine (Drugs.com)
Discussion
Mirtazapine, broken down and described (Disregard Everything I Say)
Mirtazapine can be administered via oral. The route of administration can influence both the onset and intensity of restless legs.