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Abstral Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Abstral (fentanyl) sublingual is a narcotic analgesic used to treat severe pain in cancer patients who are already receiving and who are tolerant to opioid therapy for their underlying persistent cancer pain. Common side effects include nausea, drowsiness, dizziness, confusion, or constipation.

The recommended dosage of Abstral tablets for adults is 1 tablet (100 mcg) sublingually (placed under the tongue) for each pain episode. Your doctor may adjust your dose as needed. Abstral adds to the effects of alcohol and other CNS depressants. Discuss with your doctor all medications and supplements you are taking because Abstral interacts with several other drugs. Abstral increases the risk of respiratory depression, medication errors, and potential abuse. Abstral use in pregnant women has not been adequately studied. Fentanyl is excreted in human milk; do not use Abstral if you are breastfeeding. Withdrawal symptoms may occur if you suddenly stop using Abstral.

Our Abstral (fentanyl) sublingual 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.

What is Patient Information in Detail?

Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.

Abstral in Detail - Patient Information: Side Effects

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

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

  • slow heart rate, weak or shallow breathing, sighing, severe drowsiness;
  • confusion, extreme fear, unusual thoughts or behavior; or
  • feeling like you might pass out.

Less serious side effects may include:

  • dry mouth, nausea, vomiting, constipation;
  • headache, drowsiness, tired feeling; or
  • white patches or sores inside your mouth or on your lips.

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 Abstral (Fentanyl Sublingual Tablets) »

What is Patient Information Overview?

A concise overview of the drug for the patient or caregiver from First DataBank.

Abstral Overview - Patient Information: Side Effects

SIDE EFFECTS: Nausea, vomiting, constipation, lightheadedness, dizziness, drowsiness, or headache may occur. Some of these side effects may decrease after you have been using this medication for a while. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

To prevent constipation, eat a diet adequate in fiber, drink plenty of water, and exercise. Ask your pharmacist for help in selecting a laxative (such as a stimulant type with stool softener).

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if any of these serious side effects occur: mental/mood changes (such as agitation, confusion, hallucinations), severe stomach/abdominal pain, difficulty urinating.

Get medical help right away if any of these serious side effects occur: fainting, seizure, slow/shallow breathing, unusual drowsiness/difficulty waking up.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

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

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the entire patient information overview for Abstral (Fentanyl Sublingual Tablets)»

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Abstral FDA Prescribing Information: Side Effects
(Adverse Reactions)


Clinical Studies Experience

Because clinical trials are conducted under widely varying conditions, adverse event 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 ABSTRAL has been evaluated in 311 opioid-tolerant cancer patients with breakthrough pain. Two hundred and seventy (270) of these patients were treated in multiple-dose studies. The duration of therapy for patients in multiple-dose studies ranged from 1-405 days with an average duration of 131 days and with 44 patients treated for at least 12 months.

The most commonly observed adverse reactions with ABSTRAL include typical opioid adverse reactions, such as nausea, constipation, somnolence and headache. Expect opioid side effects and manage them accordingly.

The clinical trials of ABSTRAL were designed to evaluate safety and efficacy in treating patients with cancer and breakthrough pain; all patients were taking concomitant opioids, such as sustained-release morphine, sustained-release oxycodone or transdermal fentanyl, for their persistent pain.

The adverse reaction data presented in Table 2 reflect the actual percentage of patients experiencing reactions among patients who received ABSTRAL for breakthrough pain along with concomitant opioid use for persistent pain. There has been no attempt to correct for concomitant use of other opioids, duration of ABSTRAL therapy or cancer-related symptoms.

Table 2 lists adverse reactions with an overall frequency of 5% or greater within the total population that occurred during titration by maximum dose received. The ability to assign ABSTRAL a dose-response relationship to these adverse reactions is limited by the titration schemes used in these studies.

Table2: Adverse Reactions Which Occurred During Titration at a Frequency of ≥ 5%

System Organ Class
Preferred term N (%)
100 mcg
200 mcg
300 mcg
400 mcg
600 mcg
800 mcg
Gastrointestinal disorders
Nausea 1 (4.5) 4 (17.4) 5 (9.1) 1 (2.6) 2 (3.8) 2 (2.5) 15 (5.6)
Nervous system disorders
Somnolence 0 2 (8.7) 4 (7.3) 2 (5.3) 2 (3.8) 2 (2.5) 12 (4.4)
Dizziness 0 0 3 (5.5) 2 (5.3) 0 1 (1.3) 6 (2.2)
Headache 0 0 0 1 (2.6) 3 (5.8) 1 (1.3) 5 (1.9)

Table 3 lists, by successful dose, adverse reactions with an overall frequency of ≥ 5% within the total population that occurred after a successful dose had been determined.

Table3: Adverse Reactions Which Occurred During Maintenance Therapy at a Frequency of ≥ 5%

System Organ Class
Preferred term N (%)
100 mcg
200 mcg
300 mcg
400 mcg
600 mcg
800 mcg
Gastrointestinal disorders
Nausea 1 (14.3) 0 2 (9.1) 0 1 (2.9) 6 (8.3) 10 (6.0)
Stomatitis 0 1 (8.3) 1 (4.5) 0 0 1 (1.4) 3 (1.8)
Constipation 0 0 1 (4.5) 2 (10.0) 1 (2.9) 4 (5.6) 8 (4.8)
Dry mouth 0 0 0 1 (5.0) 2 (5.7) 0 3 (1.8)
Nervous system disorders
Headache 0 0 0 2 (10.0) 1 (2.9) 2 (2.8) 5 (3.0)
Dysgeusia 1 (14.3) 0 0 0 0 1 (1.4) 2 (1.2)
General disorders and administration site conditions
Fatigue 0 0 0 1 (5.0) 2 (5.7) 0 3 (1.8)
Injury, poisoning and procedural complications
Accidental overdose 1 (14.3) 0 0 0 0 0 1 (0.6)
Respiratory, thoracic and mediastinal disorders
Dyspnoea 0 1 (8.3) 0 0 0 0 1 (0.6)
Skin and subcutaneous disorders
Hyperhidrosis 1 (14.3) 0 0 0 0 1 (1.4) 2 (1.2)

The frequencies listed below represent adverse reactions that occurred in ≥ 1% of patients from two clinical trials who experienced that reaction while receiving ABSTRAL. Reactions are classified by system organ class.

Adverse Reactions ( ≥ 1%)

Cardiac disorders: bradycardia, tachycardia.

Eye disorders: vision blurred.

Gastrointestinal disorders: abdominal pain, abdominal pain upper, aphthous stomatitis, constipation, dry mouth, dyspepsia, gingival ulceration, impaired gastric emptying, lip ulceration, mouth ulceration, nausea, stomach discomfort, stomatitis, tongue disorder, vomiting.

General disorders and administration site conditions: asthenia, drug withdrawal syndrome, fatigue, malaise.

Immune system disorders: drug hypersensitivity.

Injury, poisoning and procedural complications: accidental overdose.

Metabolism and nutrition disorders: anorexia, decreased appetite.

Nervous system disorders: amnesia, disturbance in attention, dizziness, dysgeusia, headache, hypoesthesia, lethargy, parosmia, somnolence, tremor.

Psychiatric disorders: affect lability, anxiety, confusional state, depression, disorientation, dysphoria, euphoric mood, insomnia, mental status changes, paranoia, sleep disorder.

Reproductive system and breast disorders: erectile dysfunction.

Respiratory, thoracic and mediastinal disorder: dyspnea, oropharyngeal pain, throat tightness.

Skin and subcutaneous disorders: hyperhidrosis, night sweats, pruritus, rash, skin lesion.

Vascular disorders: hypotension.

Read the entire FDA prescribing information for Abstral (Fentanyl Sublingual Tablets) »


Abstral - User Reviews

Abstral User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Abstral sorted by most helpful. Patient Discussions FAQs

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