Amitriptyline belongs to a family of medications known as tricyclic antidepressants. It is used to treat depression. It works in the central nervous system (CNS) to elevate the mood of people with depression. It is believed to work by keeping the balance of natural chemicals (neurotransmitters) in the body, namely serotonin and norepinephrine. It may start to work within 3 to 4 days, but it may take up to 30 days to see the full effects.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The usual starting dose of amitriptyline for depression in adults is 25 mg 3 times a day. The dose of amitriptyline is usually started low and increased slowly as prescribed by the doctor until the medication is at a dose that is appropriate and effective. After symptoms improve, the dose may be reduced to the lowest amount that will relieve symptoms. The usual maintenance dose of amitriptyline for adults ranges from 50 mg to 100 mg per day in divided doses. For some people, the daily dose can be given as a single dose, preferably at bedtime.

Amitriptyline may be taken with food or on an empty stomach. Swallow the tablets whole with some water. Do not crush or chew the tablets.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to amitriptyline or any ingredients of the medication
• are taking a monoamine oxidase inhibitor (MAOI; e.g., phenelzine, tranylcypromine, moclobemide) or have taken one in the past 14 days
• have acute congestive heart failure
• have recently had a heart attack
• have severely decreased liver function

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• black tongue
• constipation
• diarrhea
• dizziness
• drowsiness
• dry mouth
• headache
• heartburn
• itching
• nausea
• sore mouth
• stomach pain
• sweating
• swollen glands
• tiredness or weakness (mild)
• unpleasant taste
• vomiting
• weight changes

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• agitation
• anxiety
• breast enlargement (men and women)
• changed interest in sexual activity
• confusion
• decreased sexual ability
• decreased coordination
• difficulty concentrating
• emotional changes (e.g., feeling angry, agitated, hostile or impulsive, violent, less inhibited or controlled)
• hallucinations (hearing or seeing things that aren't there)
• increased sensitivity to sunlight
• irritability
• loss of balance control
• numbing or tingling of the fingers or toes
• problems urinating
• ringing or buzzing in the ears
• shaking
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• slurred speech
• symptoms of bowel blockage (e.g., swollen abdomen, constipation, abdominal pain)
• symptoms of high blood pressure (e.g., headache, fatigue, vision problems)
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• symptoms of low blood sugar (e.g., cold sweat, cool pale skin, headache, fast heartbeat, weakness)
• symptoms of heart problems (e.g., shortness of breath, fatigue, swelling in legs, ankles, feet, lightheadedness, chest pain, pounding heartbeat)
• symptoms of irregular heartbeat (e.g., chest pain, dizziness, rapid, pounding heartbeat, shortness of breath)
• symptoms of glaucoma (e.g., blurred vision, seeing halos of bright colours around lights, red eyes, increased pressure in your eyes, eye pain or discomfort)
• symptoms of mania (e.g., elevated or irritated mood, decreased need for sleep, racing thoughts, uneasiness)
• tremors or shakiness
• trouble sleeping
• withdrawal symptoms (e.g., nausea, headache, irritability, dreaming, problems sleeping, generally feeling unwell, changed behaviour)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• seizures
• symptoms of a severe allergic reaction (e.g., swelling of face and tongue, difficulty breathing, hives)
• signs of a heart attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
• signs of stroke (e.g., sudden or severe headache; sudden loss of coordination; vision changes; sudden slurring of speech; or unexplained weakness, numbness, or pain in arm or leg)
• symptoms of serotonin toxicity (e.g., confusion, fast heartbeat, hallucinations, restlessness, shaking, shivering, sudden jerking of muscles, sweating)
• thoughts of self-harm or suicide

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Abnormal heart rhythms: Amitriptyline has been linked to changes to the normal rhythm of the heart, including an irregular heartbeat called QT prolongation. QT prolongation is a serious life-threatening condition that can cause fainting, seizures, and sudden death. If you are at risk for heart rhythm problems (e.g., people with heart failure, angina, low potassium or magnesium levels), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Alcohol and other medications that cause drowsiness: Do not combine this medication with alcohol or other medications that cause drowsiness (e.g., antidepressants, sleeping pills, anxiety medications) because amitriptyline can also cause drowsiness and the combination can be dangerous.

Drowsiness/reduced alertness: Amitriptyline may reduce mental or physical abilities required for performance of hazardous tasks, such as operating machinery or driving a motor vehicle. Do not undertake such activities until you have determined that it does not have this effect on you.

Heart diseases:  Amitriptyline can worsen symptoms of heart disease. If you have a history of heart attack, angina, stroke, "mini-stroke", or are at risk of experiencing low blood pressure (e.g., dehydration, taking medications for high blood pressure), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Low blood pressure: Symptoms of low blood pressure, such as weakness or dizziness, particularly when rising suddenly from a sitting or lying position, may occur. People who are prone to low blood pressure (e.g., people taking diuretics) should be cautious when using this medication.

Mania or hypomania: Amitriptyline may cause activation of mania or hypomania. If you experience symptoms such as hallucinations, mania (feeling unusually over-excited or uninhibited), or delusional thinking, or notice them in a family member who is taking this medication, contact your doctor as soon as possible.

People with a history of bipolar disorder should be closely monitored by their doctor while using this medication.

Medical conditions: People with the following conditions should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed:

• benign prostatic hyperplasia (enlarged prostate)
• certain blood disorders
• increased eye pressure
• reduced liver function
• narrow-angle glaucoma
• seizures
• urinary retention

Suicidal or agitated behaviour: People taking antidepressants such as amitriptyline may feel agitated (restless, anxious, aggressive, emotional, trouble sleeping, and feeling not like themselves), or they may want to hurt themselves or others. If you notice any changes in mood, behaviours, thoughts, or feelings in yourself or someone who is taking this medication, contact a doctor immediately. Your doctor will monitor you closely for behaviour changes, especially at the start of treatment or when your dose is increased or decreased.

Serotonin toxicity: Severe reactions are possible when amitriptyline is combined with other medications that act on serotonin, such as monoamine oxidase inhibitors (MAOIs) and serotonin reuptake inhibitors, other classes of medications used to treat depression, as well as certain medications used to treat migraine headaches, nausea, and vomiting. Symptoms of a reaction may include muscle rigidity and spasms, difficulty moving, changes in mental state including delirium and agitation. Coma and death are possible.

Surgery: Using amitriptyline before, during, and after surgery may increase the risk of developing abnormal heart rhythms. The risks and benefits of continuing amitriptyline during elective surgery should be discussed with your doctor. Your doctor may recommend to stop or reduce the dose of amitriptyline several days prior to the scheduled surgery.

Thyroid disease: Patients who have an overactive thyroid (hyperthyroidism) or are taking thyroid medication should be monitored closely by their doctor when taking amitriptyline. People who are taking certain thyroid medications have an increased risk of developing an irregular heartbeat when taking amitriptyline.

Withdrawal: Stopping this medication abruptly after taking it for a long time may produce nausea, headache, and a general feeling of being unwell. Gradual dosage reduction has been reported to produce (within 2 weeks) transient symptoms including irritability, restlessness, and dream and sleep disturbance. Experiencing these symptoms does not mean you are addicted. Do not suddenly stop taking this medication if you have been taking it for a while. If you are to stop taking this medication, contact your doctor, who will advise you on how to gradually stop this medication.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and are taking amitriptyline, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 18 years of age.

There may be an interaction between amitriptyline and any of the following:

• abiraterone
• aclidinium
• alcohol
• amantadine
• amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
• antiarrhythmics (e.g., amiodarone, disopyramide, dronedarone, procainamide, sotalol)
• anticholinergic medications (e.g., atropine, oxybutynin)
• azole antifungals (e.g., fluconazole, itraconazole, ketoconazole)
• antihistamines (e.g., cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
• antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
• asunaprevir
• barbiturates (e.g., butalbital, phenobarbital)
• benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
• benztropine
• beta-2 agonists (e.g., salmeterol, formoterol, terbutaline)
• botulinum toxin
• brimonidine
• bromocriptine
• buprenorphine
• bupropion
• buspirone
• butorphanol
• cabergoline
• cannabis
• chloral hydrate
• cholinesterase inhibitors (e.g., donepezil, galantamine, rivastigmine)
• cimetidine
• cinacalcet
• clonidine
• dantrolene
• decongestant nasal sprays (e.g., oxymetazoline, phenylephrine, naphazoline)
• desmopressin
• dextromethorphan
• diphenoxylate
• domperidone
• efavirenz
• entacapone
• ergot alkaloids (e.g., ergotamine, dihydroergotamine)
• esketamine
• ethopropazine
• flibanserin
• flunarizine
• general anesthetics (medications used to put people to sleep before surgery)
• glucagon
• glycopyrrolate
• guanfacine
• HIV protease inhibitors (e.g., darunavir, tipranavir)
• lemborexant
• levodopa
• levothyroxine
• linezolid
• liothyronine
• lithium
• MAO inhibitors (e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
• meperidine
• methadone
• methylphenidate
• metoclopramide
• minocycline
• mirtazapine
• muscle relaxants (e.g., baclofen, cyclobenzaprine, orphenadrine, tizanidine)
• nabilone
• nitrates
• nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., celecoxib, diclofenac, ibuprofen, naproxen)
• olopatadine
• opioid analgesics (e.g., codeine, fentanyl, morphine, oxycodone, tramadol)
• overactive bladder medications (e.g., darifenacin, fesoterodine, mirabegron, solifenacin, tolterodine)
• ozanimod
• peginterferon alfa-2B
• perampanel
• pitolisant
• pizotifen
• pomalidomide
• potassium chloride
• pramlintide
• pramipexole
• primidone
• protein kinase inhibitors (e.g., dacomitinib, lapatinib, selpercatinib, vandetanib)
• prucalopride
• quinine
• quinolone antibiotics (e.g., ciprofloxacin, ofloxacin)
• rifampin
• ropinirole
• rotigotine
• scopolamine
• St. John's wort
• seizure medications (e.g., carbamazepine, levetiracetam, phenytoin, topiramate, valproic acid)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, fluvoxamine, sertraline, vortioxetine)
• serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine, venlafaxine)
• serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
• terbinafine
• tetrabenazine
• thalidomide
• thiazide diuretics (water pills; e.g., hydrochlorothiazide, indapamide, metolazone)
• tiotropium
• trazodone
• trihexyphenidyl
• other tricyclic antidepressants (e.g., clomipramine, desipramine, trimipramine)
• "triptan" migraine medications (e.g., almotriptan, eletriptan, rizatriptan, sumatriptan)
• tryptophan
• warfarin
• yohimbine
• zolpidem
• zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.