Mirtazapine (Remeron, Zispin, Remergil, etc.)
Mirtazapine has been produced by Organon Biosciences International since 1966. It has a unique chemical structure and unique properties. It is a tetracyclic antidepressant and it increases serotonin and norepinephrine in the synaptic cleft through a different mechanism than other antidepressants.
The Bottom Line: What You Really Need to Know
- Mirtazapine is used to treat depression and other conditions. It is often added to dosulepine or venlefaxine to treat resistant or severe depression.
- The usual starting dose of mirtazapine is 15 mg/day at bedtime. It can be gradually increased up to 45 mg/day if necessary.
- Mirtazapine interacts with several other medications. Make sure you tell your physician and pharmacist about all medications that you take, including herbal remedies and teas, over the counter medications, homeopathic and alternative treatments, vitamins, supplements and medications you only take occasionally.
- Talk to your doctor before you stop taking mirtazapine. Your dose may need to be tapered down slowly to prevent uncomfortable withdrawal symptoms.
- Most people experience a few mild side effects, like drowsiness or vivid dreams, when they begin taking mirtazapine. They usually go away with time.
- Have a friend or family member check in with you every day for the first few weeks that you take mirtazapine. Ask him or her to help you monitor your condition for:
- Worsening depression
- Restlessness, irritability, agitation, hostility or aggression
- Unusual thoughts or thoughts of suicide
- Report any serious or unusual side effects to your doctor.
Uses
Mirtazapine is approved for the treatment of mild to severe depression. It is also used to treat Panic Disorder, anxiety, OCD, PTSD and hives. Mirtazapine is not usually used as a first line antidepressant; rather, it is often added to duloxetine or venlefaxine to treat severe or resistant depression.
Dosage and instructions
The usual starting dose for mirtazapine is 15 mg/day at bedtime. The dose can be slowly increased to a maximum of 45 mg/day. Mirtazapine is available as a dissolving tablet and can be taken without food or water.
How mirtazapine works
Depression is thought to be caused by an inadequate amount of certain neurotransmitters in the gap between nerve cells (the synaptic cleft or gap). Antidepressants work in different ways to increase the levels of some of the neurotransmitters.
Mirtazapine increases the level of norepinephrine by blocking receptors that keep it from being released. It increases serotonin levels the same way, plus it may improve transmission between nerve cells by enhancing serotonin uptake in the post-synaptic cell.
Mirtazapine doesn't have much of an effect on other neurotransmitters except for histamine. It blocks histamine much the same as Benedryl does.
Side effects
The most common effects that people experience while taking mirtazapine are increased appetite, weight gain, drowsiness, nausea and headache. Other side effects that have been reported include:
- Vivid dreams and nightmares
- Increased cholesterol llevels
- Dizziness and nausea
- Swelling
- Hallucinations
- Manic attacks
- Tremors and twitches
- Seizures
- Restless Leg Syndrome
- Rashes and allergic reactions
- Joint or muscle pain
- Blood pressure problems
Interactions
Although mirtazapine does not interact with medications to the degree that other antidepressants do, there are some potential drug interactions you should be aware of.
MAOI antidepressants: Mirtazapine should not be taken within two weeks of taking a MAOI antidepressant. A serious reaction that includes high fever, high blood pressure and seizures could result.
Sedating medications: Mirtazapine has a sedating effect, and if you take other sedating medications with it, the effects will be enhanced. Narcotics, barbiturates, sleeping pills, antianxiety pills and antihistamines can all cause oversedation when taken with mirtazapine.
Other medications that interact with mirtazapine include tricyclic antidepressants, some blood pressure medications and fluvoxamine.
Warnings, precautions and contraindications
Suicide risk: There appears to be an increased risk for suicide with all antidepressants, especially when you first start taking them. Anyone who starts taking a new antidepressant should be monitored for several weeks for potential suicidal thoughts. You should see your physician or therapist weekly and have someone check on you every day to see how you are doing. If they notice or you experience any of the following, it should be reported to the doctor immediately:
- Worsening depression
- Sudden mood changes
- Restlessness, anxiety, agitation, hostility
- Unusual thoughts or emotions
- Hallucinations
- Thoughts of hurting yourself or others.
Bipolar disorder: Mirtazapine should not be used in treating bipolar disorder unless mood stabilizers are also being used. It can precipitate manic episodes that may be mild or severe, and can lead to delusions, psychosis and rapid cycling.
Agranulocytosis: A few people have developed agranulocytosis while taking mirtazapine. This is a condition in which there are very few disease-fighting cells in your bloodstream, which makes you susceptible to infections. Notify your doctor if you experience mouth sores, sores that won't heal or become easily infected, fever, sore throat or any other unusual symptoms.
Mirtazapine should be used with caution in people who have any of the following conditions:
- Seizure disorder
- Liver disease
- Heart disease
- Low blood pressure
- Enlarged prostate gland
- Glaucoma
- Diabetes
- Schizophreni