Fentanyl citrate (By mouth)


Fentanyl (FEN-ta-nil)

Treats cancer pain in patients whose pain is not always relieved by other pain medicines. This medicine is a narcotic pain reliever.

Brand Name(s)

Onsolis, Fentora

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

You should not use this medicine if you have had an allergic reaction to fentanyl. You should not use this medicine until after you have tried other narcotic medicines. Do not use this medicine if you need pain medicine for just a short time, such as during a headache or migraine attack, or when recovering from surgery or an injury.

How to Use This Medicine

Thin Sheet, Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Your dose may need to be changed several times in order to find out what works best for you. Do not use more medicine or use it more often than your doctor tells you to.
  • This medicine should come with a Medication Guide. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions. Ask your pharmacist for the Medication Guide if you do not have one.
  • Remove the tablet from the blister unit just before product use. Do not push the tablet through the blister as this may cause damage to the tablet. Do not split the tablet.
  • Do not store the tablet after removing it from the blister package. It should be used immediately.
  • Place the tablet in your mouth between the upper cheek and gum, above the back molar.
  • Allow the tablet to dissolve. It usually takes around 14 to 25 minutes for the tablet to dissolve completely.
  • Do not suck, chew, or swallow the tablet.
  • If the tablet did not dissolve completely after 30 minutes, you may swallow it with a glass of water.
  • Drink plenty of fluids to help avoid constipation.
  • Use only the brand of this medicine that your doctor prescribed. Different brands may not work the same way.
  • Fentanyl film is available only under a restricted distribution program called FOCUS® Program.
  • To use the film: Remove the film from the foil package immediately prior to product use. Do not cut or tear the film. Use your tongue to wet the side of your cheek, or rinse your mouth with water to wet the area in your mouth where you will place the film. Hold the film in place on your clean, dry finger with the pink side facing up. Press and hold the film against your cheek for 5 seconds. Leave the film in place for 15 to 30 minutes until it dissolves. Do not touch or move the film while it dissolves. If your doctor tells you to use more than one film, place the new film on the other side of your mouth.
  • This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Do not refrigerate or freeze.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Any unopened buccal tablets and films that are no longer needed should also be disposed of promptly. Flush the tablets and films down the toilet after removing from the blister packages. Do not flush the blister packages or cartons down the toilet.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are also using clarithromycin (Biaxin®), itraconazole (Sporanox®), ketoconazole (Nizoral®), nefazodone (Serzone®), or troleandomycin (Tao®). Tell your doctor if you are also using aprepitant (Emend®), cimetidine (Tagamet®), diltiazem (Cardizem®, Dilacor XR®), erythromycin (Ery-Tab®), fluconazole (Diflucan®), telithromycin (Ketek®), or verapamil (Calan®, Isoptin®, or Verelan®). Make sure your doctor knows if you have used an MAO inhibitor (MAOI), such as Eldepryl®, Marplan®, Nardil®, or Parnate® within the past 14 days.
  • Make sure your doctor knows if you are also using St. John's wort, modafinil (Provigil®), pioglitazone (Actos®), rifabutin (Mycobutin®), rifampin (Rimactane®), troglitazone (Rezulin®), medicine for HIV or AIDS (such as amprenavir, efavirenz, fosamprenavir, indinavir, nelfinavir, nevirapine, ritonavir, saquinavir, Agenerase®, Crixivan®, Fortovase®, Invirase®, Lexiva®), Norvir®, Sustiva®, Viracept®, or Viramune®), or medicine for seizures (such as carbamazepine, oxcarbazepine, phenobarbital, phenytoin, Dilantin®, or Tegretol®).
  • Tell your doctor if you are using any medicines that make you sleepy. These include sleeping pills, cold and allergy medicine, narcotic pain relievers, and sedatives.
  • Do not drink alcohol while you are using this medicine.
  • Do not eat grapefruit or drink grapefruit juice while you are using this medicine.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, lung disease or breathing problems such as chronic obstructive pulmonary disease (COPD), low blood pressure, heart rhythm problems, seizures (convulsions), depression, or mental problems. Also tell your doctor if you have had a recent head injury or other problems that could increase the pressure in your head. Tell your doctor if you also have a history of drug or alcohol abuse or addiction.
  • This medicine may cause problems with breathing, which can be serious and life-threatening. This is more likely in patients with lung disorders, the elderly, very weak patients, or those who use large doses of this medicine. Call your doctor right away if you have shortness of breath, or irregular, fast, slow, or shallow breathing after taking this medicine.
  • This medicine may make you dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert. You may also feel lightheaded when standing up suddenly from a sitting or lying position, so get up slowly.
  • This medicine can cause serious illness or even death if taken by a child or by anyone who is not already taking prescription medicine on a regular schedule for cancer pain.
  • If you are switching from the oral transmucosal form of fentanyl to buccal form, make sure you read the patient instruction carefully. These forms are very different.
  • Do not stop using this medicine suddenly without asking your doctor. You may need to slowly decrease your dose before stopping it completely.
  • This medicine may be habit-forming. If you feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions.
  • If your symptoms do not improve or if they get worse, call your doctor.
  • This medicine may cause constipation. This is more common if you use it for a long time. Ask your doctor if you should also use a laxative to prevent and treat constipation.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Bleeding, sores, pain, or irritation where you placed the medicine.
  • Chest pain.
  • Dry mouth, increased thirst, muscle cramps, nausea, or vomiting.
  • Fast, slow, or uneven heartbeat.
  • Fever, chills, cough, sore throat, and body aches.
  • Lightheadedness, dizziness, severe drowsiness, or fainting.
  • Pain in your lower leg (calf).
  • Pain on urination, change in how much or how often you urinate.
  • Rapid weight gain.
  • Shortness of breath, or irregular, fast, slow, or shallow breathing.
  • Sores or white patches on your lips, mouth, or throat.
  • Swelling in your hands, ankles, or feet.
  • Unusual bleeding or bruising.
  • Unusual tiredness or weakness.
  • Yellowing of your skin or the whites of your eyes.

If you notice these less serious side effects, talk with your doctor:

  • Back or joint pain.
  • Confusion or depression.
  • Constipation, diarrhea, or stomach pain.
  • Headache.
  • Loss of appetite.
  • Numbness, tingling, or burning pain in your hands, arms, legs, or feet.
  • Trouble sleeping.
  • Weight loss.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last Reviewed on 06/12/2013

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