Dacomitinib belongs to the group of cancer-fighting medications known as antineoplastics. Specifically, it belongs to the class of medications called tyrosine kinase inhibitors. It works by recognizing certain types of cancer cells and blocking the action of chemicals that cause them to divide and grow. This may slow down or stop cancers from growing and dividing.

Dacomitinib is used in adults to treat non-small-cell lung cancer that cannot be removed by surgery or has spread to other parts of the body. It is not appropriate for all types of non-small cell lung cancer. It will only interfere with the growth of cancer cells that have a particular mutation (a change) in the "epidermal growth factor receptor". Your doctor should test your cancer for this change in the "EGFR" receptor before starting this medication.

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 adult dose of dacomitinib is 45 mg taken by mouth once daily. It may be taken with food or on an empty stomach, however it should be taken at approximately the same time every day and under the same conditions. For example, if you start taking dacomitinib with food, continue to take it with food, at the same time each day.

Many things can affect the dose of 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 vomit after taking dacomitinib, do not take another dose. Continue with your regular dosing schedule.

If you miss a 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.

15 mg
Each blue, film-coated, immediate-release, round, biconvex tablet, debossed with "Pfizer" on one side and "DCB15" on the other, contains 15 mg of dacomitinib, as dacomitinib monohydrate. Nonmedicinal ingredients: lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium starch glycolate; film coating: Opadry II® Blue 85F30716 containing: FD&C Blue No. 2/Indigo Carmine Aluminum Lake, Macrogol/PEG 3350, polyvinyl alcohol – part hydrolyzed, talc, and titanium dioxide.

30 mg
Each blue, film-coated, immediate-release, round, biconvex tablet, debossed with "Pfizer" on one side and "DCB30" on the other, contains 30 mg of dacomitinib, as dacomitinib monohydrate. Nonmedicinal ingredients: lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium starch glycolate; film coating: Opadry II® Blue 85F30716 containing: FD&C Blue No. 2/Indigo Carmine Aluminum Lake, Macrogol/PEG 3350, polyvinyl alcohol – part hydrolyzed, talc, and titanium dioxide.

45 mg
Each blue, film-coated, immediate-release, round, biconvex tablet, debossed with "Pfizer" on one side and "DCB45" on the other, contains 45 mg of dacomitinib, as dacomitinib monohydrate. Nonmedicinal ingredients: lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium starch glycolate; film coating: Opadry II® Blue 85F30716 containing: FD&C Blue No. 2/Indigo Carmine Aluminum Lake, Macrogol/PEG 3350, polyvinyl alcohol – part hydrolyzed, talc, and titanium dioxide.

Do not take this medication if you are allergic to dacomitinib or any ingredients of the 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.

• acne
• arm or leg pain
• changed sense of taste
• cold-like symptoms (e.g., cough, nasal congestion)
• constipation
• dry, itchy eyes
• dry, peeling skin
• fatigue
• hair loss
• increased hair growth
• increased sensitivity to sunlight
• itching
• mild diarrhea
• mouth sores
• muscle pain
• nausea
• rash
• shortness of breath
• trouble sleeping
• vomiting
• weakness
• weight loss

Although most of the 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:

• blisters inside the mouth
• signs of dehydration (e.g., decreased urine, dry skin, dry and sticky mouth, sleepiness, dizziness, headache, thirst, confusion)
• diarrhea
• eye problems (e.g., redness, pain, increased tearing, blurred vision, decreased vision, increased sensitivity to light, feeling like something is trapped in your eye)
• pain, redness, warmth, swelling of the skin around fingernails or toenails
• signs of breathing problems (e.g., shortness of breath, troubled breathing, wheezing, or tightness in chest, fast or irregular breathing)
• tingling, numbness, pain, rash, swelling, or redness of the palms of the hands or soles of the feet

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

• severe dehydration (e.g., unable to urinate for 12 hours, fainting, trouble breathing, high fever)

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.

Birth control: Use effective birth control while using this medication, as this medication may harm the baby if used during pregnancy. Both men and women should use effective birth control (e.g., condoms, birth control pill) during treatment and for at least 2 months after treatment is finished. If you or your partner become pregnant while taking this medication, contact your doctor immediately.

Diarrhea: Dacomitinib commonly causes diarrhea, which, if it is severe, can lead to dehydration because of fluid loss. While you are taking dacomitinib, make sure you are drinking plenty of fluids. If you experience diarrhea, talk to your doctor. Severe dehydration can cause rapid loss of kidney function and is a medical emergency. If you experience symptoms of dehydration such as decreased tears, sweating, urine production, constipation, headache, or muscle cramps, seek medical attention.

Eye problems: You may experience changes in vision while taking this medication. Tell your doctor if you experience eye pain or redness, or any vision disturbances, such as flashes of light, blurry vision, or double vision.

Liver function: Dacomitinib may reduce liver function and can cause liver problems. Your doctor will monitor your liver function with blood tests while you are taking this medication. If you have liver 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.

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Lung inflammation: Some people taking this medication have experienced lung inflammation (interstitial lung disease) causing difficulty breathing. This complication can be serious and sometimes fatal. If you experience new or worsening shortness of breath or cough (with or without fever) at any time while you are taking dacomitinib, contact your doctor immediately.

Nail changes: Dacomitinib can cause infection of the skin surrounding the fingernails or toenails. It is important to keep your hands and feet clean and dry, be gentle when trimming your nails and avoid injury to the nails or finger tips. Use gentle soaps and nail products, avoiding harsh soaps and detergents with chemicals. If you experience symptoms of an infection of the nail or nailbed, such as redness, swelling, heat, or pain, contact your doctor as soon as possible.

Skin changes: Dacomitinib can cause changes to the skin, making it dry or red, and can cause acne and peeling. Blisters may form on the palms of the hands and soles of the feet. Applying a good moisturizer to the skin from the time you start taking dacomitinib may help to reduce how severe these effects become. If you experience blistering or peeling skin, report this to your doctor as soon as possible.

This medication may increase the sensitivity of the skin to sunlight, increasing the risk of sunburn. Avoid exposure to sunlight for long periods of time, particularly between the hours of 10 am and 2 pm, while you are taking this medication. Wear a broad-spectrum sunscreen and lip balm with an SPF of 30 or greater. If you notice any unusual skin rash or peeling, contact your doctor immediately.

Pregnancy: Although the safety and effectiveness of this medication when used during pregnancy haven’t been determined, it is expected that it is likely to cause harm to an unborn baby if it is taken by the mother during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if dacomitinib passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Due to the risk of serious harm to a baby if they are exposed to this medication, breast-feeding mothers are advised not to use this medication. In addition, breast-feeding should not be started until at least 2 months after taking the last dose of dacomitinib.

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

Seniors: People over the age of 65 may experience side effects of this medication.

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

• amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
• antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, pimozide, quetiapine, risperidone)
• atomoxetine
• captopril
• carvedilol
• chloroquine
• chlorpheniramine
• codeine
• dextromethorphan
• doxorubicin
• duloxetine
• eliglustat
• fesoterodine
• flecainide
• galantamine
• H2 antagonists (e.g., famotidine, ranitidine)
• hydrocodone
• maprotiline
• methamphetamine
• metoprolol
• mirtazapine
• primaquine
• procainamide
• propafenone
• propranolol
• mexiletine
• proton pump inhibitors (e.g., lansoprazole, omeprazole, rabeprazole)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• tamoxifen
• tamsulosin
• tetrabenazine
• timolol
• tolterodine
• tramadol
• tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
• venlafaxine

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.