Last updated on RxList: 3/25/2021
Onsolis Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Onsolis?

Onsolis (fentanyl buccal) Soluble Film is a narcotic (opioid) pain medicine used to treat "breakthrough" cancer pain that is not controlled by other medicines. Onsolis is taken together with other non-fentanyl narcotic pain medicine that is used around the clock. Onsolis is not for treating pain that is not cancer-related. The brand name Onsolis is discontinued, but generic versions may be available.

What Are Side Effects of Onsolis?

Common side effects of Onsolis (fentanyl buccal) include nausea, vomiting, constipation, lightheadedness, dizziness, drowsiness, headache, feeling weak or tired, swelling in your hands or feet, or pain or mouth sores where the medicine was placed.

Dosage for Onsolis

All patients MUST begin treatment using one 200 mcg dose of Onsolis film.

What Drugs, Substances, or Supplements Interact with Onsolis?

Onsolis may interact with other narcotics, sedatives, tranquilizers, sleeping pills, muscle relaxers, other medicines that can make you sleepy or slow your breathing, dexamethasone, imatinib, isoniazid, St. John's wort, antibiotics, antifungals, antidepressants, heart or blood pressure medications, HIV medications, or seizure medications. Tell your doctor all medications and supplements you use.

Onsolis During Pregnancy and Breastfeeding

Before using Onsolis, tell your doctor if you are pregnant or if you plan to become pregnant. During pregnancy, Onsolis should be used only when prescribed. It may slightly increase the risk of birth defects if used during the first two months of pregnancy. Using it near the expected delivery date may harm the fetus. Tell the doctor if you notice symptoms in your newborn baby such as slow/shallow breathing, irritability, abnormal/persistent crying, vomiting, or diarrhea. This drug passes into breast milk and may rarely have undesirable effects on a nursing infant. Tell the doctor if your baby develops unusual sleepiness, difficulty feeding, or trouble breathing. Consult your doctor before breastfeeding. Withdrawal symptoms may occur if you suddenly stop taking this medication.

Additional Information

Our Onsolis (fentanyl buccal) Soluble Film Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

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.


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Onsolis Consumer Information

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

Like other opioid medications, fentanyl can slow or stop your breathing. If your breathing gets too weak, death may occur.

Your caregivers will watch for any of these side effects, which may clear up within minutes after stopping the fentanyl infusion or decreasing the dose:

  • weak or shallow breathing;
  • fast or slow heart rate;
  • stiff muscles; or
  • severe weakness, feeling light-headed or fainting.

Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.

Common side effects may include:

  • slowed breathing;
  • slow heart rate;
  • muscle stiffness;
  • dizziness, vision problems;
  • nausea, vomiting;
  • itching, sweating; or
  • high blood pressure (confusion, anxiety, pounding in your neck or ears).

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.

Read the entire detailed patient monograph for Onsolis (Fentanyl Buccal Soluble Film)

Onsolis Professional Information


The following serious adverse reactions are described, or described in greater detail, in other sections:

  • Life-Threatening Respiratory Depression [see WARNINGS AND PRECAUTIONS]
  • Interactions with Benzodiazepines and other CNS Depressants [see WARNINGS AND PRECAUTIONS]
  • Addiction, Abuse, and Misuse [see WARNINGS AND PRECAUTIONS]
  • Neonatal Opioid Withdrawal Syndrome [see WARNINGS AND PRECAUTIONS]
  • Serotonin Syndrome [see WARNINGS AND PRECAUTIONS]
  • Adrenal Insufficiency [see WARNINGS AND PRECAUTIONS]
  • Severe Hypotension [see WARNINGS AND PRECAUTIONS]
  • Gastrointestinal Adverse Reactions [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety of ONSOLIS has been evaluated in 306 opioid tolerant patients with breakthrough cancer pain in an efficacy study and an open-label safety study. The mean duration of therapy was 115 days, with 32 patients treated for more than 1 year.

The most serious adverse reactions associated with all opioids including ONSOLIS are respiratory depression (potentially leading to apnea or respiratory arrest), circulatory depression, hypotension, and shock. Follow all patients for symptoms of respiratory depression.

Because the clinical trials of ONSOLIS were designed to evaluate safety and efficacy in treating patients with breakthrough pain associated with cancer, all patients were also taking concomitant opioids, such as sustained-release morphine, sustained-release oxycodone or transdermal fentanyl, for their persistent cancer pain. The adverse event data presented here reflect the actual percentage of patients experiencing each adverse event among patients who received ONSOLIS for breakthrough cancer pain along with a concomitant opioid for persistent cancer pain. There has been no attempt to correct for concomitant use of other opioids, duration of ONSOLIS therapy, or cancer-related symptoms. Adverse reactions are included regardless of severity.

Table 1 lists, by maximum dose received, adverse reactions with an overall frequency of 5% or greater that occurred during titration. The ability to assign a dose-response relationship to these adverse reactions is limited by the titration schedules used in these studies. Adverse reactions are listed in descending order of frequency within each body system.

Table 1 : Adverse Reactions Which Occurred During Titration at a Frequency of ≥5%

System Organ Class, Preferred Term, n (%) ONSOLIS Dose (mcg) Total
Gastrointestinal Disorders
Nausea 16 (5) 12 (5) 6 (3) 5 (4) 4 (5) 0 42 (14)
Vomiting 7(2) 9 (4) 8 (4) 2 (1) 0 0 26 (8)
Nervous System Disorders
Dizziness 5 (2) 5 (2) 6 (3) 2 (1) 4 (5) 0 22 (7)
Somnolence 6 (2) 2 (1) 4 (2) 2 (1) 4 (5) 1 (11) 17 (6)

Table 2 lists, by successful dose, adverse reactions with an overall frequency of ≥5% that occurred during long-term treatment (i.e., the double-blind or open-label maintenance periods).

Table 2 : Adverse Reactions Which Occurred During Long-Term Treatment at a Frequency of ≥5%

System Organ Class Preferred Term n (%) ONSOLIS Dose (mcg) Total
Nausea 2 (9) 6 (10) 8 (10) 12 (13) 26 (32) 4 (14) 56 (26)
Vomiting 1 (4) 5 (8) 9 (11) 8 (9) 23 (28) 3 (11) 45(21)
Constipation 2 (9) 4 (7) 4 (5) 4 (4) 6 (7) 4 (14) 23 (11)
Diarrhea 1 (4) 1 (2) 4 (5) 4 (4) 10 (12) 0 19 (9)
Dry mouth 1 (4) 4 (7) 3 (4) 2 (2) 3 (4) 1 (4) 14 (7)
Abdominal pain 0 0 3 (4) 1 (1) 7 (9) 1 (4) 11 (5)
General/administration site
Asthenia 0 6 (10) 3 (4) 8 (9) 7 (9) 4 (14) 28 (13)
Fatigue 2 (9) 6 (10) 1 (1) 7 (8) 7 (9) 3 (11) 25 (12)
Weight decreased 3 (13) 0 2 (3) 5 (5) 5 (6) 1 (4) 15 (7)
Dehydration 1 (4) 4 (7) 6 (8) 5 (5) 10 (12) 3 (11) 28 (13)
Decreased appetite 0 4 (7) 4 (5) 6 (7) 2 (2) 2 (7) 18 (8)
Anorexia 2 (9) 1 (2) 3 (4) 4 (4) 6 (7) 1 (4) 17 (8)
Nervous system
Dizziness 2 (9) 4 (7) 2 (3) 3 (3) 10 (12) 2 (7) 23 (11)
Headache 2 (9) 1 (2) 3 (4) 9 (10) 7 (9) 0 20 (9)
Somnolence 2 (9) 0 4 (5) 2 (2) 3 (4) 3 (11) 14 (7)
Confusional state 1 (4) 0 4 (5) 4 (4) 6 (7) 4 (14) 18 (8)
Depression 0 3 (5) 1 (1) 4 (4) 7 (9) 3 (11) 18 (8)
Insomnia 0 2 (3) 2 (3) 3 (3) 4 (5) 2 (7) 12 (6)
Anxiety 1 (4) 1 (2) 2 (3) 3 (3) 3 (4) 1 (4) 11 (5)
Dyspnea 3 (13) 4 (7) 3 (4) 8 (9) 6 (7) 3 (11) 26 (12)
Cough 1 (4) 0 3 (4) 5 (5) 6 (7) 1 (4) 15 (7)
Hypotension 0 3 (5) 3 (4) 1 (1) 3 (4) 1 (4) 11 (5)

In a mucositis study, a group of patients (n=7) with Grade 1 oral mucositis and a matched group of control patients (n=7) without oral mucositis were included in a clinical trial designed to support the safety of ONSOLIS. The adverse event profile was similar in both subsets of patients. There was no evidence that ONSOLIS caused or worsened oral mucosal irritation or pain in either study group.

The duration of exposure to ONSOLIS varied greatly and included open-label and double-blind studies. The adverse reactions listed below represent those that were reported by ≥1% of patients from two clinical trials (the titration and post-titration periods) while receiving ONSOLIS. Events are classified by system organ class.

Cardiac disorders: tachycardia

Eye disorders: vision blurred, diplopia

Gastrointestinal disorders: nausea, vomiting, constipation, diarrhea, dry mouth, abdominal pain, dyspepsia, dysphagia, abdominal distension, intestinal obstruction, flatulence

General disorders and administration site conditions: asthenia, fatigue, malaise

Injury, poisoning and procedural complications: fall, contusion

Investigations: weight decreased, blood pressure increased

Metabolism and nutrition disorders: dehydration, decreased appetite, anorexia

Nervous system disorders: dizziness, somnolence, headache, lethargy, amnesia, sedation

Psychiatric disorders: confusional state, depression, insomnia, anxiety, hallucination, agitation, mental status changes

Renal and urinary disorders: urinary retention

Respiratory, thoracic and mediastinal disorders: dyspnea, cough

Skin and subcutaneous tissue disorders: pruritus, rash

Vascular disorders: hypotension, hot flush, deep vein thrombosis, hypertension

Postmarketing Experience

The following adverse reactions have been identified during post approval use of fentanyl. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Serotonin Syndrome

Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concomitant use of opioids with serotonergic drugs.

Adrenal Insufficiency

Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use.


Anaphylaxis has been reported with ingredients contained in ONSOLIS.

Androgen Deficiency

Cases of androgen deficiency have occurred with chronic use of opioids [see CLINICAL PHARMACOLOGY].


Table 3 includes clinically significant drug interactions with ONSOLIS.

Table 3 : Clinically Significant Drug Interactions with ONSOLIS

Inhibitors of CYP3A4
Clinical Impact: The concomitant use of ONSOLIS and CYP3A4 inhibitors can increase the plasma concentration of fentanyl, resulting in increased or prolonged opioid effects, particularly when an inhibitor is added after a stable dose of ONSOLIS is achieved [see WARNINGS AND PRECAUTIONS].
After stopping a CYP3A4 inhibitor, as the effects of the inhibitor decline, the fentanyl plasma concentration will decrease [see CLINICAL PHARMACOLOGY], resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependence to fentanyl.
Intervention: If concomitant use is necessary, consider dosage reduction of ONSOLIS until stable drug effects are achieved. Monitor patients for respiratory depression and sedation at frequent intervals.
If a CYP3A4 inhibitor is discontinued, consider increasing the ONSOLIS dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.
Examples Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g. ketoconazole), protease inhibitors (e.g., ritonavir)
CYP3A4 Inducers
Clinical Impact: The concomitant use of ONSOLIS with CYP3A4 inducers can decrease the plasma concentration of fentanyl [see CLINICAL PHARMACOLOGY], resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to fentanyl [see WARNINGS AND PRECAUTIONS].
After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase [see CLINICAL PHARMACOLOGY], which could increase or prolong both the therapeutic effects and adverse reactions and may cause serious respiratory depression.
Intervention: If concomitant use is necessary, consider increasing the ONSOLIS dosage until stable drug effects are achieved [see DOSAGE AND ADMINISTRATION]. Monitor for signs of opioid withdrawal. If a CYP3A4 inducer is discontinued, consider ONSOLIS dosage reduction and monitor for signs of respiratory depression.
Examples Rifampin, carbamazepine, phenytoin
Benzodiazepines and other Central Nervous System (CNS) Depressants
Clinical Impact: Due to additive pharmacologic effect, the concomitant use of benzodiazepines or other CNS depressants, including alcohol, increases the risk of respiratory depression, profound sedation, coma, and death.
Intervention: Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor patients for signs of respiratory depression and sedation [see WARNINGS AND PRECAUTIONS]. If concomitant use is warranted, consider prescribing naloxone for the emergency treatment of opioid overdose [see DOSAGE AND ADMINISTRATION, WARNINGS AND PRECAUTIONS].
Examples: Benzodiazepines and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, other opioids, alcohol.
Serotonergic Drugs
Clinical Impact: The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome [see WARNINGS AND PRECAUTIONS].
Intervention: If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue ONSOLIS if serotonin syndrome is suspected.
Examples: Selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that affect the serotonin neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), certain muscle relaxants (i.e., cyclobenzaprine, metaxalone), monoamine oxidase (MAO) inhibitors (those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue).
Monoamine Oxidase Inhibitors (MAOIs)
Clinical Impact: MAOI interactions with opioids may manifest as serotonin syndrome [see WARNINGS AND PRECAUTIONS] or opioid toxicity (e.g., respiratory depression, coma) [see WARNINGS AND PRECAUTIONS].
Intervention: The use of ONSOLIS is not recommended for patients taking MAOIs or within 14 days of stopping such treatment.
Examples: phenelzine, tranylcypromine, linezolid
Mixed Agonist/Antagonist and Partial Agonist Opioid Analgesics
Clinical Impact: May reduce the analgesic effect of ONSOLIS and/or precipitate withdrawal symptoms.
Intervention: Avoid concomitant use.
Examples: butorphanol, nalbuphine, pentazocine, buprenorphine
Muscle Relaxants
Clinical Impact: Fentanyl may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression.
Intervention: Monitor patients for signs of respiratory depression that may be greater than otherwise expected and decrease the dosage of ONSOLIS and/or the muscle relaxant as necessary. Due to the risk of respiratory depression with concomitant use of skeletal muscle relaxants and opioids, consider prescribing naloxone for the emergency treatment of opioid overdose [see DOSAGE AND ADMINISTRATION, WARNINGS AND PRECAUTIONS]
Examples: Cyclobenzaprine, metaxalone
Clinical Impact: Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone.
Intervention: Monitor patients for signs of diminished diuresis and/or effects on blood pressure and increase the dosage of the diuretic as needed.
Anticholinergic Drugs
Clinical Impact: The concomitant use of anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Intervention: Monitor patients for signs of urinary retention or reduced gastric motility when ONSOLIS is used concomitantly with anticholinergic drugs.

Read the entire FDA prescribing information for Onsolis (Fentanyl Buccal Soluble Film)

© Onsolis Patient Information is supplied by Cerner Multum, Inc. and Onsolis Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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