How does this medication work? What will it do for me?

Duloxetine belongs to the class of medications called selective serotonin and norepinephrine reuptake inhibitors (SSNRIs). It is used to treat depression and generalized anxiety disorder. It can also be used to treat diabetes-related nerve pain, fibromyalgia, chronic low back pain, and chronic pain from osteoarthritis of the knee.

For depression and anxiety, duloxetine works by affecting the balance of chemicals in the brain and other parts of the body. For certain types of pain, duloxetine works by affecting the balance of chemicals in the brain and spinal cord that are involved in the experience of pain.

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.

What form(s) does this medication come in?

30 mg
Each delayed-release capsule with opaque white body and opaque blue cap, imprinted "30 mg" on the body and "9543" on the cap, contains duloxetine 30 mg. Nonmedicinal ingredients: FD&C Blue No. 2, gelatin, hydroxypropyl methylcellulose, hydroxypropyl methylcellulose acetate succinate, sodium lauryl sulfate, sucrose, sugar spheres, talc, titanium dioxide, and triethyl citrate.

60 mg
Each delayed-release capsule with opaque green body and opaque blue cap, imprinted "60 mg" on the body and "9542" on the cap, contains duloxetine 60 mg. Nonmedicinal ingredients: FD&C Blue No. 2, gelatin, hydroxypropyl methylcellulose, hydroxypropyl methylcellulose acetate succinate, sodium lauryl sulfate, sucrose, sugar spheres, talc, titanium dioxide, triethyl citrate, and yellow iron oxide.

How should I use this medication?

The usual recommended dose is 60 mg once daily. Some people may start on a lower dose of 30 mg once daily. Elderly patients with generalized anxiety disorder should be started at a dose of 30 mg once daily. It usually starts to work within 1 to 4 weeks for depression and anxiety and within the first week of treatment for diabetes-related nerve pain, fibromyalgia, chronic back pain, and chronic osteoarthritis knee pain.

Duloxetine should be taken at the same time each day. It can be taken with or without food, but taking it with food may help to reduce nausea that may occur at the start of treatment.

Swallow capsules whole. Do not crush or chew the capsules, and do not sprinkle the contents of the capsule into foods or liquids.

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 by a few hours, take it as soon as you remember and continue with your regular schedule. If most of the day has passed, 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 dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to duloxetine or any ingredients of the medication
  • have liver disease causing reduced liver function
  • have severely reduced kidney function
  • have uncontrolled narrow-angle glaucoma
  • are taking fluvoxamine and other medications with a similar effect on drug metabolism in the liver (check with your pharmacist)
  • are taking MAO inhibitors (e.g., phenelzine, tranylcypromine, linezolid, methylene blue) or have taken a MAO inhibitor within 2 weeks of starting duloxetine
  • are taking quinolone medications (e.g., ciprofloxacin, norfloxacin)
  • are taking thioridazine

What side effects are possible with this medication?

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.

  • changes in sexual desire or ability
  • constipation
  • decreased appetite
  • diarrhea
  • difficulty sleeping
  • dizziness
  • dry mouth
  • fatigue
  • headache
  • heartburn
  • increased sweating
  • nausea
  • restlessness (feeling like you need to keep moving)
  • sleepiness
  • vomiting

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

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

  • hallucinations
  • inability to pass urine
  • new or worsening emotional or behavioural problems
  • overactive thoughts or behaviour
  • signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood,  bleeding gums, cuts that don’t stop bleeding)
  • skin rash or hives (with no other symptoms)
  • 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 high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
  • symptoms of liver problems (e.g., nausea, vomiting, or loss of appetite, combined with yellow skin or eyes, dark urine, or itching)
  • symptoms of low sodium levels in the blood (e.g., tiredness, weakness, and confusion combined with achy, stiff, or uncoordinated muscles)
  • uncontrollable face or body movements

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

  • seizures
  • signs of an allergic reaction (e.g., shortness of breath or difficulty breathing; hives, itching or rash; swelling of the eyes, mouth, lips, or throat)
  • signs of bleeding in the stomach (e.g., bloody, black, or tarry stools, spitting up of blood, vomiting blood or material that looks like coffee grounds)
  • signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
  • symptoms of serotonin syndrome or neuroleptic malignant syndrome (e.g., experiencing most or all of the following: confusion, restlessness, extreme agitation, high fever, sweating, shivering, shaking, hallucinations, fast heartbeat, and sudden muscle jerking)

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.

Are there any other precautions or warnings for 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.

Bleeding: This medication may increase the risk of bleeding, especially if you are also taking medications such as acetylsalicylic acid (ASA), nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., ibuprofen, naproxen, ketoprofen), or warfarin. If you experience easy bruising, pinpoint-sized red spots on the skin, or unusual bleeding while taking this medication, contact your doctor immediately.

Blood pressure and heart rate: Duloxetine may cause an increase in blood pressure or heart rate. Your doctor will monitor your blood pressure and heart rate before starting this medication and periodically while you are taking this medication. If you have high blood pressure or other types of heart disease, 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.

Bone fractures: Duloxetine may increase your risk of breaking a bone, especially if you are a senior, have osteoporosis, or have other risk factors for bone fractures. Take extra care to avoid falling by sitting or lying down if you feel dizzy or lightheaded. Contact your doctor if you experience dizziness or lightheadedness frequently.

Diabetes: This medication may worsen blood sugar control in some people who have diabetes. If you have diabetes, monitor your blood sugar closely and report any changes to your doctor.

If you are at risk for developing diabetes, 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.

Drowsiness/reduced alertness: This medication may affect judgment, thinking, or physical abilities and may cause drowsiness or dizziness. Avoid driving, operating machinery, or performing other hazardous tasks until you have determined how this medication affects you.

Glaucoma: This medication may cause the symptoms of glaucoma (increased pressure in the eye) to become worse. If you have controlled narrow-angle glaucoma, 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. Report any changes in vision to your doctor as soon as possible while you are taking this medication.

Kidney function: Duloxetine is not recommended for people with severe kidney problems. If you have kidney problems, 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.

Liver function: This medication may cause liver problems. If you experience nausea, abdominal pain, or yellowing of the skin or eyes while taking this medication, contact your doctor immediately. If you have liver problems or consume substantial amounts of alcohol, 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.

Seizures: If you have a seizure disorder, 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.

Serotonin Syndrome /Neuroleptic Malignant Syndrome: Severe reactions are possible when duloxetine is combined with other medications that act on serotonin, such as tricyclic antidepressants and certain migraine medications. These combinations must be avoided. Symptoms of a reaction may include muscle rigidity and spasms, difficulty moving, and changes in mental state including delirium and agitation. Coma and death are possible.

If you are taking antidepressants, 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.

Slowed stomach emptying: If you have a condition that slows emptying from the stomach (e.g., diabetes), 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.

Stopping the medication: Stopping this medication suddenly may lead to side effects such as dizziness, abnormal dreams, difficulty sleeping, numbness or tingling sensations, irritability, anxiety, nausea, vomiting, diarrhea, sweating, muscle pain or other symptoms. Stopping this medication gradually as directed by your doctor can minimize these effects. If you are thinking of stopping the medication, check with your doctor first.

Suicidal or agitated behaviour: People taking this medication may feel agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or they may want to hurt themselves or others. If you experience these side effects or notice them in a family member who is taking this medication, contact your doctor immediately. Your doctor will monitor you closely for these side effects while you are taking this medication.

Pregnancy: It has been reported that babies born to women who took medications similar to duloxetine during the last trimester of their pregnancy may experience adverse effects (such as breathing problems, seizures, trouble feeding, jitteriness, irritability, and constant crying). 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 a breast-feeding mother and are taking duloxetine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children and adolescents: The safety and effectiveness of this medication have not been established for children. Children under 18 years are at an increased risk of suicidal thoughts or behaviour if they take duloxetine.

What other drugs could interact with this medication?

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

  • abiraterone acetate
  • acetylsalicylic acid (ASA)
  • alcohol
  • aldesleukin
  • aliskiren
  • alpha/beta agonists (e.g., epinephrine, norepinephrine)
  • alpha blockers (e.g., alfuzosin, doxazosin, tamsulosin)
  • alpha agonists (e.g., clonidine, methyldopa)
  • amiodarone
  • amphetamines (e.g., dextroamphetamine, lisdexamphetamine)
  • angiotensin converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
  • angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
  • anti-psychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzepine, quetiapine, risperidone)
  • apixaban
  • aripiprazole
  • atomoxetine
  • beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
  • brimonidine
  • bromocriptine
  • bupropion
  • buspirone
  • cabergoline
  • calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
  • carbamazepine
  • certain antiarrhythmic medications (e.g., flecainide, propafenone)
  • celecoxib
  • chloroquine
  • chlorpheniramine
  • chlorpromazine
  • cilostazol
  • cinacalcet
  • chloroquine
  • clobazam
  • clopidogrel
  • cocaine
  • cyclobenzaprine
  • cyproterone
  • dabigatran
  • deferasirox
  • delavirdine
  • dextromethorphan
  • dipyridamole
  • diuretics (water pills; e.g., furosemide, hydrochlorothiazide, triamterene)
  • dronedarone
  • ethinyl estradiol
  • ergot alkaloids (e.g., ergotamine, dihydroergotamine)
  • gemfibrozil
  • glucosamine
  • guanfacine
  • heparin
  • isoniazid
  • ketoconazole
  • linezolid
  • lithium
  • lopinavir
  • lorazepam
  • low molecular weight heparins (e.g., dalteparin, enoxaparin, tinzaparin)
  • methadone
  • methoxsalen
  • metoclopramide
  • mexiletine
  • minoxidil
  • mirabegron
  • mirtazapine
  • monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
  • meperidine
  • multivitamins with minerals
  • nitrates (e.g., nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
  • nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., ibuprofen, naproxen, ketoprofen)
  • peginterferon Alfa-2b
  • pentoxifylline
  • phenobarbital
  • primaquine
  • primidone
  • procainamide
  • quinidine
  • quinine
  • quinolone antibiotics (e.g., ciprofloxacin, enoxacin, norfloxacin)
  • rifampin
  • ritonavir
  • rivaroxaban
  • St. John's wort
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, duloxetine, fluoxetine, paroxetine, sertraline)
  • serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
  • serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine, venlafaxine)
  • tamoxifen
  • tapentadol
  • terbinafine
  • ticagrelor
  • ticlopidine
  • tramadol
  • trazodone
  • tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline, desipramine)
  • triptans (e.g., sumatriptan, rizatriptan)
  • tryptophan
  • tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib)
  • vitamin E
  • warfarin

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.