Mirtazapine
Treating insomnia with medication often involves a delicate balance between trying to promote sleep whilst trying to prevent addiction and tolerance issues.
As an alternative approach, doctors often turn to medications with sedative side effects. These drugs are prescribed “off-label,” meaning they are utilised for conditions outside of their official licensing in an attempt to address insomnia.
One such medication frequently employed in this manner is mirtazapine. In the UK, mirtazapine holds a license for treating major depression, obsessive-compulsive disorder, and anxiety. However, mirtazapine is occasionally employed off-label to aid in sleep, owing to its sedative qualities that can facilitate both falling and staying asleep.
Research suggests that mirtazapine may effectively alleviate insomnia symptoms in individuals with depression. Furthermore, it has been observed to augment REM sleep. Consequently, a mental health professional might suggest mirtazapine for individuals grappling with insomnia.
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Mirtazapine is a prescription-only drug in the UK.
You will need to speak to a doctor before receiving this medicine.
Begin Treatment QuizWhat you should know about mirtazapine
Mirtazapine is a medication primarily used for major depressive disorders, in addition to panic disorder, generalised anxiety disorder and posttraumatic stress disorder. However, it can also be used off licence to treat insomnia.
Although mirtazapine is primarily used for depression, it can also be prescribed “off licence” for insomnia. This is because one of its side effects is sedation, which is thought to be caused by its actions on the neurotransmitters serotonin and histamine.
Mirtazapine belongs to the class of drugs known as serotonin and norepinephrine receptor antagonists (SN-Ran). It can also be described as an alpha 2 antagonist, NaSSA (noradrenaline and specific serotonergic agent), or a dual serotonin and norepinephrine agent.
It works by boosting the neurotransmitters serotonin and norepinephrine/noradrenaline. It also blocks alpha-2 adrenergic presynaptic receptors, thereby increasing norepinephrine neurotransmission. This blockage of the alpha-2 adrenergic presynaptic receptor on serotonin neurons (heteroreceptors) also increases serotonin neurotransmission. Mirtazapine also blocks the 5HT2A, 5HT2C, and 5HT3 serotonin receptors and H1 histamine receptors.
It is thought the histamine 1 receptor antagonism may explain mirtazapine’s sedative effects.
The onset of mirtazapine’s effects may require several weeks to become evident. According to NHS guidelines, when mirtazapine is utilised to address depression or anxiety, it may take approximately 4-6 weeks for beneficial outcomes to manifest.
In the case of low-dose mirtazapine administered for sleep disturbances, its impact may begin to be felt within 1-2 weeks of initial ingestion. However, the timing and extent of these effects can vary among individuals. While some individuals may experience improved sleep from the first dose, the effects may manifest more gradually for others.
Mirtazapine has demonstrated efficacy in shortening the time it takes for individuals to fall asleep and decreasing nocturnal awakenings, thereby enhancing the overall continuity and quality of sleep.
Although off-label utilisation of mirtazapine for insomnia may appear promising, it’s essential to acknowledge the potential side effects associated with its use.
Mirtazapine should be taken exactly as prescribed by your healthcare provider. It is typically taken just before bedtime, with a full glass of water. Do not crush or chew mirtazapine tablets. You may take mirtazapine with or without food.
No, mirtazapine is a prescription-only medicine (POM), which means you need an NHS or private prescription before you can buy mirtazapine.
Unlike other medicines that can be purchased from online pharmacies after completing a questionnaire, mirtazapine requires a phone or video consultation with a registered doctor specialising in sleep disorders. This is because, in addition to being a prescription-only medicine (POM), it is also a controlled drug (CD), which means there are additional controls relating to its supply.
Sleephelp does not sell mirtazapine tablets but allows you to book an appointment to speak to Dr Zak Taylor, our consultant psychiatrist. If a private prescription for mirtazapine is generated after the consultation with Dr Taylor, it is sent to the pharmacy we work with to dispense.
Mirtazapine is not expected to cause addiction.
Side effects are frequently experienced with mirtazapine use and may encompass the following:
- Feelings of anxiety, dizziness, and confusion
- Increased appetite, water retention, and weight gain
- Dry mouth, joint pain, and muscle aches
- Drowsiness, fatigue, and sleep disturbances
- Gastrointestinal issues like diarrhoea, nausea, constipation, and vomiting.
It’s noteworthy that mirtazapine can induce ‘sleep disorders’, with fatigue being a common occurrence as well. While mirtazapine might aid in better sleep while being consumed, insomnia can develop after discontinuation of the medication.
Given its sedative properties, mirtazapine can lead to daytime drowsiness and may leave individuals feeling groggy or experiencing mild hangover sensations, emphasising the importance of adhering to prescribed dosages.
Moreover, mirtazapine may elevate the incidence of restless legs syndrome and periodic limb movements, both of which can significantly disrupt sleep patterns. Weight gain is also frequently cited as a side effect of mirtazapine, with research suggesting that the drug may slightly alter metabolism and increase cravings for sugary foods.
Extended use of mirtazapine is generally regarded as safe, with minimal risk of lasting adverse effects even after months or years of use. However, caution should be exercised when discontinuing the medication.
As is common with many antidepressants, abruptly halting mirtazapine intake is not recommended. Doing so can precipitate withdrawal symptoms, which may manifest as:
- Headaches and dizziness
- Nausea and vomiting
- Feelings of anxiety and agitation.
Mirtazapine is offered in various doses, including 15mg, 30mg, and 45mg, in both standard and dispersible tablet formulations. Additionally, it is available in liquid form, with a concentration of 15mg per ml.
For individuals seeking relief from sleep disturbances, mirtazapine is usually prescribed at a lower dose. The sedative effects of mirtazapine are believed to be more pronounced at lower doses and diminish as the dose increases.
Typically, an initial dose of 7.5mg of mirtazapine is prescribed for use at bedtime. However, some individuals may find that a dose as low as 3.75mg is optimal for their needs.
Mirtazapine does not interfere with any form of contraception, including the combined pill or emergency contraception.
However, if mirtazapine causes vomiting or severe diarrhoea persisting for more than 24 hours, your contraceptive pills may not provide full protection against pregnancy. Refer to the instructions in your pill packet for guidance.
For further information on what to do if you’re experiencing vomiting or diarrhoea while taking the pill, please refer to the relevant resources.
Some individuals may experience difficulty concentrating while taking mirtazapine, and it can also induce drowsiness.
It is advisable to refrain from driving or cycling during the initial days of mirtazapine treatment until you understand how the medication affects you.
Driving a vehicle while impaired is illegal if it compromises your ability to drive safely. It is your responsibility to assess whether you are fit to drive. If uncertain, refrain from driving.
Consult your doctor or pharmacist if you have any doubts about driving while using mirtazapine. Additional information on drug laws and driving can be found on the GOV.UK website.
While consuming alcohol is permissible while taking mirtazapine, it may induce drowsiness and unsteadiness.
For the initial days of treatment, it might be prudent to abstain from alcohol until you ascertain how the medication influences you.
Regular or excessive alcohol consumption can exacerbate your symptoms and hinder the effectiveness of mirtazapine.
There are no dietary restrictions while taking mirtazapine so you can eat and drink as usual.
Combining cannabis with mirtazapine can induce pronounced drowsiness, especially if you’ve recently started taking mirtazapine.
It’s risky to mix mirtazapine with:
- Methadone
- Stimulants such as MDMA (ecstasy) or cocaine
- Hallucinogens like LSD
- Novel psychoactive substances (formerly known as legal highs) like mephedrone
You can learn more about the side effects of certain recreational drugs on the Frank website.
Please note that mirtazapine’s interactions with recreational drugs have not been thoroughly studied. If you’re considering using recreational drugs while on mirtazapine, it’s crucial to discuss this with your doctor first.
Some individuals may not be suitable candidates for mirtazapine. Before initiating treatment, inform your doctor if you:
- Have previously experienced an allergic reaction to mirtazapine or any other medication.
- Have a heart condition, as mirtazapine may lower blood pressure.
- Have previously used other antidepressants, as certain fewer common antidepressants may interact with mirtazapine, resulting in dangerously high blood pressure even several weeks after discontinuation.
- Have glaucoma, as mirtazapine has the potential to elevate eye pressure.
- Have epilepsy, as although uncommon, mirtazapine may heighten the risk of seizures.
- Are attempting to conceive, currently pregnant, or breastfeeding.
There is limited evidence suggesting that mirtazapine use in early pregnancy may not significantly impact the baby’s development.
However, taking mirtazapine in the weeks leading up to delivery may occasionally lead to short-term withdrawal symptoms or, in rare cases, breathing difficulties in the newborn. Babies are routinely monitored after birth, and if necessary, they receive additional care.
Using mirtazapine in the final month of pregnancy might slightly elevate the risk of post-delivery bleeding. Despite this rare occurrence, many women opt to continue mirtazapine treatment during pregnancy due to its benefits.
However, mirtazapine is generally not recommended for use during pregnancy, especially in the first trimester.
It remains crucial to address mental health concerns adequately during pregnancy, as they can affect both the mother and the baby’s overall well-being. Depression and anxiety may exacerbate during pregnancy and postpartum periods. If you become pregnant, consult your doctor promptly. They will assist you in evaluating the potential risks and benefits, enabling you to make informed decisions regarding the most suitable treatment for you and your baby.
If your healthcare provider confirms your baby’s health, mirtazapine can typically be taken while breastfeeding.
Mirtazapine transfers into breast milk in minimal quantities and has commonly been used during breastfeeding without notable issues.
While there may be other medications preferred during breastfeeding, prioritising the medication that effectively treats your condition is essential. If you are currently breastfeeding or planning to do so, consulting with your doctor or pharmacist can aid in determining the best course of action.
Should you observe any changes in your baby’s feeding patterns, such as decreased appetite, excessive sleepiness, or unusual irritability, or if you have any other concerns regarding your baby, promptly seek advice from your healthcare provider, midwife, pharmacist, or doctor.
There is no definitive evidence indicating that mirtazapine impacts fertility in men or women.
If you are considering pregnancy while using mirtazapine, it is advisable to discuss this with your doctor.
Certain medications may interact with mirtazapine, potentially increasing the risk of experiencing side effects.
Inform your doctor or pharmacist if you are taking:
- Other antidepressants, especially if you have taken them recently. Some antidepressants can interact with mirtazapine, leading to elevated blood pressure even after discontinuation.
- Medications that induce drowsiness, such as potent painkillers like morphine or muscle relaxants like diazepam.
- Tramadol increases the risk of seizures in patients taking antidepressants.
- Warfarin, as mirtazapine may influence its effects, necessitating a potential adjustment in your warfarin dosage.
- Antiepileptic drugs such as carbamazepine or phenytoin, which can diminish the efficacy of mirtazapine. In such cases, your doctor may prescribe a higher dose of mirtazapine.
- Rifampicin is an antibiotic that can reduce the effectiveness of mirtazapine. In this scenario, your doctor may need to prescribe a higher dosage.
Additionally, it’s crucial to avoid taking mirtazapine if you have recently taken monoamine oxidase inhibitors (MAOIs) or if you are currently on them. Combining these medications can lead to a potentially fatal condition called serotonin syndrome, characterised by symptoms such as confusion, hallucinations, rapid heart rate, high blood pressure, fever, sweating, shivering, trembling, muscle twitching, loss of coordination, nausea, vomiting, and diarrhoea. If you have any concerns or questions about potential drug interactions, consult your healthcare provider for guidance and appropriate management.
Avoid consuming the herbal remedy St John’s wort while undergoing treatment with mirtazapine, as it heightens the risk of experiencing adverse effects.
The safety of other herbal remedies or supplements with mirtazapine is uncertain, as they undergo different testing procedures compared to pharmacy and prescription medicines.
Here are several strategies you can employ to alleviate insomnia and promote better sleep:
- Establish a consistent sleep schedule by going to bed and waking up at the same time each day.
- Engage in relaxation techniques before bedtime, such as taking a warm bath or listening to calming music.
- Create a conducive sleep environment by using thick curtains or blinds, wearing an eye mask, and using earplugs to minimise disturbances from light and noise.
- Avoid consuming stimulants like caffeine, nicotine, alcohol, heavy meals, and engaging in vigorous exercise in the hours leading up to bedtime.
- To limit screen time, avoid watching TV or using electronic devices such as phones, tablets, or computers before bed.
- Avoid daytime napping to ensure better nighttime sleep.
- Practice writing down worries and potential solutions before bedtime to ease your mind and promote relaxation.
While over-the-counter sleeping tablets available at pharmacies may offer temporary relief from insomnia, they are not a cure and may have undesired side effects. It is advisable to limit their use to 1 to 2 weeks and seek advice from a pharmacist before taking them.
