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Onsolis

Generic name: fentanyl (buccal)

Brand names: Fentora (discontinued), Onsolis (discontinued)

Last updated October 1, 2026 0 views Reviewed by Carmen Pope, Senior Medical Editor, B. Pharm
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What is Onsolis?

Onsolis was a buccal soluble film that contained fentanyl, a narcotic (opioid) pain medicine.

Onsolis was used to treat "breakthrough" cancer pain that was not controlled by other medicines. Onsolis was taken together with other non-fentanyl narcotic pain medicines used around the clock. This medication was not for treating pain that was not cancer-related, such as general headaches or back pain.

Onsolis has been discontinued, and generic fentanyl buccal soluble film is not available. This information is retained for educational purposes only and may not be up to date.

Warnings

Because of the risks of addiction, abuse, and misuse, overdose, and death with opioids, which can occur at any dosage or duration and persist over the course of therapy, reserve buccal/sublingual fentanyl for use in cancer patients for whom alternative treatment options (such as non-opioid analgesics or immediate-release opioids) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain.

Onsolis is available only under special programs called Fentora REMS or the FOCUS Program. You must be registered in the program and sign documents stating that you understand the risks and benefits of taking this medication.

Do not use Onsolis unless you are already being treated with a similar opioid pain medicine and your body is tolerant to it. Talk with your doctor if you are not sure you are opioid-tolerant.

Onsolis is used to treat "breakthrough" cancer pain. This medication is not for treating pain that is not cancer-related, such as general headaches or back pain.

Do not use Onsolis if you have severe asthma or breathing problems, a bowel blockage or narrowing of the stomach or intestines, or if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days.

Before using Onsolis, tell your doctor if you have a breathing disorder, a head injury or brain tumor, seizures, mental illness, a heart rhythm disorder, low blood pressure, liver or kidney disease, or a history of drug or alcohol addiction.

Keep this medicine out of the reach of children or pets. The amount of fentanyl in each Onsolis buccal film can be fatal to a child or pet who accidentally sucks on or swallows it. Seek emergency medical attention if this happens. Fentanyl may be habit-forming and should be used only by the person it was prescribed for. Never share Onsolis with another person, especially someone with a history of drug abuse or addiction. Keep the medication in a place where others cannot get to it.

Before using Onsolis

Do not use Onsolis unless you are already being treated with a similar opioid pain medicine and your body is tolerant to it. Opioid medicines include morphine (Kadian, MS Contin, and others), hydrocodone (Lortab, Vicodin), oxycodone (Oxycontin), and hydromorphone (Dilaudid). Talk with your doctor if you are not sure you are opioid-tolerant. Do not use Onsolis if you have severe asthma or breathing problems, a bowel blockage or narrowing of the stomach or intestines, or if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.

To make sure you can safely take Onsolis, tell your doctor if you have any of these other conditions:

  • a breathing disorder such as chronic obstructive pulmonary disease (COPD);
  • a history of head injury or brain tumor;
  • a heart rhythm disorder;
  • seizures or epilepsy;
  • mental illness such as depression, hallucinations;
  • low blood pressure;
  • liver, kidney, or thyroid problems, problems urinating, or pancreas or gallbladder problems; or
  • a history of drug or alcohol addiction.

Fentanyl may be habit-forming and should be used only by the person it was prescribed for. Never share Onsolis with another person, especially someone with a history of drug abuse or addiction. Keep the medication in a place where others cannot get to it.

FDA pregnancy category C. It is not known whether Onsolis will harm an unborn baby. Fentanyl may cause addiction or withdrawal symptoms in a newborn if the mother takes the medication during pregnancy, which could be life-threatening if not recognized and treated. Tell your doctor if you are pregnant or plan to become pregnant while using Onsolis. Fentanyl may also cause addiction and withdrawal symptoms in a nursing infant. You should not breast-feed while you are using Onsolis.

Onsolis side effects

Get emergency medical help if you have any of these signs of an allergic reaction to Onsolis: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using Onsolis and call your doctor at once if you have a serious side effect such as:

  • weak or shallow breathing;
  • sleep apnea (breathing stops and starts during sleep);
  • pale skin, feeling light-headed or short of breath, rapid heart rate, chest pain, trouble concentrating, extreme drowsiness, agitation, confusion;
  • feeling very thirsty or hot, high body temperature, being unable to urinate, heavy sweating, hot and dry skin, trouble walking, or stiff muscles; or
  • nausea, vomiting, loss of appetite, worsening tiredness or weakness, or dizziness (may be signs of a problem with your adrenal glands).

Less serious Onsolis side effects may include:

  • nausea, vomiting, constipation;
  • dizziness, drowsiness;
  • headache;
  • feeling weak or tired, trouble sleeping, anxiety, or depression;
  • swelling in your hands or feet, rash, or abdominal pain; or
  • pain or mouth sores where the medicine was placed.

Long-term use of opioid medication may affect fertility (ability to have children) in men or women. It is not known whether opioid effects on fertility are permanent.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

How should I use Onsolis?

Use Onsolis exactly as prescribed. Never use fentanyl in larger amounts, or for longer than recommended by your doctor. Follow the directions on your prescription label. Tell your doctor if the medicine seems to stop working as well in relieving your pain.

Use the tongue to wet the inside of the cheek or rinse the mouth with water to wet the area for placement of Onsolis. Open the package immediately prior to use. Place the entire Onsolis film near the tip of a dry finger with the pink side facing up and hold in place. Place the pink side of the Onsolis film against the inside of the cheek. Press and hold the film in place for 5 seconds. The Onsolis film should stay in place on its own after this period.

Onsolis film should not be cut or torn before using.

The Onsolis film will dissolve within 15 to 30 minutes after application. The film should not be manipulated with the tongue or fingers and eating food should be avoided until the film has dissolved. You may drink liquids after 5 minutes.

If your doctor tells you to use more than one Onsolis film at the same time for your breakthrough cancer pain, do not put the films on top of each other. Onsolis films may be placed on either side of your mouth.

If you switch from using Actiq (fentanyl oral transmucosal devices) to using Fentora (fentanyl buccal tablets) or Onsolis (fentanyl buccal soluble film), you will not use the same dose. Fentora and Onsolis are given at lower doses than Actiq. Fentanyl dosage must also be adjusted if switching between Onsolis and Fentora.

If you feel dizzy, nauseated, or very sleepy while the film is still in your mouth, spit the medicine out into a sink or toilet and rinse your mouth with water to remove all remaining pieces of the film. Call your doctor for instructions.

If your pain does not completely go away, use a second film only if your doctor has approved it.

Wait at least 2 hours to treat a new pain episode with Onsolis film.

Call your doctor if you have breakthrough pain more than 4 times in one day while using this medicine.

Do not stop using Onsolis suddenly after long-term use, or you could have unpleasant withdrawal symptoms. Ask your doctor how to avoid withdrawal symptoms when you stop using Onsolis. Keep this medicine out of the reach of children or pets. The amount of fentanyl in each Onsolis film can be fatal to a child or pet who accidentally sucks on or swallows it. Seek emergency medical attention if this happens.

Store Onsolis at room temperature away from moisture and heat. Do not freeze. Keep the medicine its original package until you are ready to take your dose. Keep track of the amount of medicine used from each new bottle. Fentanyl is a drug of abuse and you should be aware if anyone is using your medicine improperly or without a prescription.

Throw away unused Onsolis films by removing them from the foil packaging and flushing them down a toilet. Disposal of medicines by flushing is recommended to reduce the danger of accidental overdose causing death. This advice applies to a very small number of medicines only. The FDA, working with the manufacturer, has determined this method to be the most appropriate route of disposal and presents the least risk to human safety

What happens if I miss a dose?

Since Onsolis is used on an as needed basis, you are not likely to miss a dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. A fentanyl overdose can be fatal. Talk to your doctor about naloxone, a medicine for the emergency treatment of an opioid overdose.

Overdose symptoms may include extreme weakness or dizziness, pinpoint pupils, cold and clammy skin, weak pulse, fainting, slow breathing (breathing may stop).

Do not use Onsolis with any other narcotic pain medications, sedatives, tranquilizers, sleeping pills, muscle relaxers, or other medicines that can make you sleepy or slow your breathing. Dangerous side effects may result. Onsolis may impair your thinking or reactions. Avoid driving or operating machinery until you know how Onsolis will affect you. Do not drink alcohol. It can increase drowsiness or breathing problems caused by Onsolis.

Grapefruit and grapefruit juice may interact with Onsolis and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor.

What other drugs will affect Onsolis?

Do not take Onsolis with any other narcotic pain medications, sedatives, tranquilizers, sleeping pills, muscle relaxers, or other medicines that can make you sleepy or slow your breathing. Dangerous side effects may result.

Tell your doctor about all other medicines you use, especially:

  • dexamethasone (Cortastat, Dexasone, Solurex, DexPak);
  • imatinib (Gleevec);
  • isoniazid (for treating tuberculosis);
  • St. John's wort;
  • an antibiotic such as clarithromycin (Biaxin), erythromycin (E.E.S., EryPed, Ery-Tab, Erythrocin, Pediazole), rifabutin (Mycobutin), rifampin (Rifadin, Rifater, Rifamate), rifapentine (Priftin), or telithromycin (Ketek);
  • antifungal medicine such as itraconazole (Sporanox), ketoconazole (Nizoral), miconazole (Oravig), or voriconazole (Vfend);
  • an antidepressant such as nefazodone;
  • heart or blood pressure medication such as diltiazem (Cartia, Cardizem), felodipine (Plendil), nicardipine (Cardene), nifedipine (Nifedical, Procardia), quinidine (Quin-G), verapamil (Calan, Covera, Isoptin, Verelan), and others;
  • HIV medication such as atazanavir (Reyataz), delavirdine (Rescriptor), efavirenz (Sustiva, Atripla), etravirine (Intelence), nelfinavir (Viracept), nevirapine (Viramune), saquinavir (Invirase), or ritonavir (Norvir, Kaletra); or
  • seizure medication such as carbamazepine (Carbatrol, Equetro, Tegretol), felbamate (Felbatol), oxcarbazepine (Trileptal), phenytoin (Dilantin), or primidone (Mysoline).

This list is not complete and other drugs may interact with Onsolis. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Tell your doctor if you also take stimulant medicines, herbal products, or medicine for depression, mental illness, Parkinson's disease, migraine headaches, serious infections, or prevention of nausea and vomiting. A dangerous drug interaction could occur, leading to a serious condition called serotonin syndrome. Do not start a new medication without telling your doctor.

Common questions about Onsolis

What drugs cause pinpoint pupils?
Pinpoint pupils, medically termed miosis, refer to abnormally small, constricted pupils that do not dilate appropriately in low light. This symptom can be caused by opioids, clonidine, buspirone, metoclopramide, and other medications. Continue reading
Which drugs cause opioid-induced constipation?
Any drug that is classified as an "opioid" can cause constipation, which can be a serious side effect if not addressed. Examples of commonly prescribed opioids that may cause this side effect include morphine, tramadol, fentanyl, methadone, hydrocodone, codeine and oxycodone. Continue reading
How long does Fentanyl stay in your system?
Traces of fentanyl can stay in your system for a lot longer than it takes for the effects of fentanyl to wear off. Drug testing can detect fentanyl or its metabolites (breakdown products) in urine for 24 to 72 hours, in blood for 5 to 48 hours, and in hair for up to 3 months, but it cannot be consistently detected in saliva. Continue reading
Carfentanil vs Fentanyl: Which is more dangerous?
Both illegally-made fentanyl and carfentanil are extremely dangerous opioids that may result in a quick overdose and death when abused, but carfentanil is more potent than fentanyl. Multiple doses of the anti-overdose drug naloxone (Narcan) or nalmefene (Opvee) may not be effective to reverse an overdose. Continue reading
Fentanyl test strips: where to get & how to use?
Fentanyl test strips can be found at your local health department, at a community needle-exchange program, from reliable online sources, or even vending machines in some states. Once the strip is dipped into a sample of the drug (usually dissolved in a small amount of water), the results indicate if fentanyl is present. Follow the instructions for use on your specific test strips. Continue reading
Why is fentanyl so dangerous?
Fentanyl is a powerful opioid that can be deadly when misused or taken in an overdose. It can quickly slow or stop breathing, especially in people who are not used to its effects. Combining fentanyl with alcohol, benzodiazepines, gabapentinoids, other opioids, or other depressants greatly increases the risk of overdose and death. Continue reading
What are the symptoms of a fentanyl overdose?
Illicit Fentanyl, a potent synthetic opioid, is a leading cause of U.S. overdose deaths. Often mixed with other drugs, it can rapidly depress breathing and cause death. Recognizing overdose signs like extreme drowsiness, slowed breathing, constricted pupils, cyanosis (blue lips, skin, fingernails), seizures, or coma is critical for timely emergency intervention. Continue reading
How does fentanyl compare to heroin or other opiates?
Fentanyl is an extremely potent, synthetic (man-made) opioid, and is about 50 times more potent than heroin and 100 times more potent than morphine. Fentanyl is a legally prescribed drug for pain in the U.S. and is classified as Schedule II controlled substance when used for legitimate medical purposes. In contrast, heroin is 2 to 3 times more powerful than morphine. Heroin is illegal in the U.S. and is classified as a Schedule I controlled substance. Continue reading

Related medicines

Before you take this medicine: the information on this page is general and may not cover your personal circumstances. Read the label supplied with your medicine and ask a pharmacist or doctor if you are unsure, especially if you are pregnant, breastfeeding, taking other medicines or managing a long-term condition.
General medicine information Consumer-friendly language Source: Drugs.com

Content is provided for education and is not medical advice. See our medical disclaimer. Source page medically reviewed by Carmen Pope, Senior Medical Editor, B. Pharm on October 1, 2026.