This medication is used to treat depression. Mirtazapine works by helping to restore the balance of certain natural substances in the brain.

Read the Medication Guide provided by your pharmacist before you start using mirtazapine and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor, usually once daily at bedtime. The dosage is based on your medical condition and response to treatment.

Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time each day. It may take 1 to 4 weeks to notice improvement in your symptoms. Do not increase your dose or take it more often than prescribed.

Keep taking this medication even if you feel well. Do not stop taking this medication without consulting your doctor. Some conditions may become worse when you suddenly stop this drug. Your dose may need to be gradually decreased.

Tell your doctor if your condition does not get better or if it gets worse.

See also the Warning section.

Dizziness, drowsiness, lightheadedness, increased appetite, weight gain, dry mouth, or constipation may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute.

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• swelling of the hands/feet
• shaking (tremor)
• confusion

Get medical help right away if you have any very serious side effects, including:

• fast/irregular heartbeat
• severe dizziness
• fainting
• eye pain/swelling/redness
• widened pupils
• vision changes (such as seeing rainbows around lights at night, blurred vision)

This medication may increase serotonin and rarely cause a very serious condition called serotonin syndrome/toxicity. The risk increases if you are also taking other drugs that increase serotonin, so tell your doctor or pharmacist of all the drugs you take (see Drug Interactions section). Get medical help right away if you develop some of the following symptoms:

• fast heartbeat
• hallucinations
• loss of coordination
• severe dizziness
• severe nausea/vomiting/diarrhea
• twitching muscles
• unexplained fever
• unusual agitation/restlessness

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• fever
• swollen lymph nodes
• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking this medication, tell your doctor or pharmacist if you are allergic to it, or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• history or family history of psychiatric disorders (such as bipolar/manic-depressive disorder)
• history or family history of suicide attempts
• liver disease
• kidney disease
• seizures
• high blood cholesterol or triglyceride levels
• heart disease (such as recent heart attack, angina)
• stroke
• severe loss of body fluids (dehydration)
• low blood pressure
• personal or family history of glaucoma (angle-closure type)

Mirtazapine may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using mirtazapine, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions:

• certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG)
• family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death)

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using mirtazapine safely.

This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Older adults may be more sensitive to the side effects of this drug, especially drowsiness and QT prolongation (see above).

During pregnancy, this medication should be used only when clearly needed. If this medication is used during the last 3 months of pregnancy, rarely your newborn may develop symptoms including feeding or breathing difficulties, seizures, muscle stiffness, jitteriness or constant crying. Report any such symptoms to your doctor promptly. However, since untreated mental/mood disorders (such as depression) can be a serious condition, do not stop taking this medication unless your doctor directs you to do so. If you are planning pregnancy, become pregnant, or think you may be pregnant, discuss with your doctor right away the benefits and risks of using this medication during pregnancy.

This drug passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before and after treatment with this medication. Ask your doctor when to start or stop taking this medication.

The risk of serotonin syndrome/toxicity increases if you are also taking other drugs that increase serotonin. Examples include street drugs such as MDMA/"ecstasy," St. John's wort, certain antidepressants (including SSRIs such as fluoxetine/paroxetine, SNRIs such as duloxetine/venlafaxine), tryptophan, among others. The risk of serotonin syndrome/toxicity may be more likely when you start or increase the dose of these drugs.

Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana (cannabis), antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), and opioid pain relievers (such as codeine, hydrocodone).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669. Symptoms of overdose may include: very fast/irregular heartbeat, severe dizziness, fainting.

Lab and/or medical tests should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

Do not share this medication with others.

If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Use your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.