The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Nausea (41%)
- Vomiting (26%)
- Sleepiness (19%)
- Dizziness (10%)
- Trouble sleeping (10%)
- Constipation (9%)
- A lot of sweating (6%)
- Tiredness (6%)
- Feeling cold (6%)
Less Common Side Effects
- Headache
- Diarrhea
- Stomach pain
- Dry mouth
- Fast heartbeat
- Feeling unwell
- Weakness
- Muscle spasms
- Numbness, burning, or tingling sensation in arms or legs
- Itching
- Rash
- Anxiety
- Confusion
Fentanyl serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Dangerously slow breathing: trouble breathing; bluish-colored lips, fingers, or toes
- Accidentally taking too much (overdose): not responding to sound or touch, slowed breathing, slow heartbeat, extreme sleepiness, cold or clammy skin
- Opioid withdrawal: anxiety, suicidal thoughts, restlessness, irritability, runny nose, yawning, sweating, chills, wide pupils
- Serious allergic reaction: itchy, red rash (hives); shortness of breath; chest tightness; swelling of lips, tongue, throat, face, or eyes
Source: DailyMed
More on Fentanyl side effects
The following Fentanyl side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Less common
bloating or swelling of the face, arms, hands, lower legs, or feet
burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
confusion
decrease in urine volume
difficulty in breathing or swallowing
difficulty in passing urine (dribbling)
fast, irregular, pounding, or racing heartbeat or pulse
rapid weight gain
seeing, hearing, or feeling things that are not there
skin itching, rash, or redness
swelling of the face, throat, or tongue
unusual weight gain or loss
upper stomach pain
Rare
Bluish color of the fingernails, lips, skin, palms, or nail beds
burning, itching, redness, skin rash, swelling, or soreness at the application site
confusion about identity, place, and time
false or unusual sense of well-being
irregular, fast or slow, or shallow breathing
Incidence not known
Agitation
blurred vision
chest pain or discomfort
darkening of the skin
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
headache
lightheadedness, dizziness, or fainting
loss of appetite
mental depression
nervousness
overactive reflexes
poor coordination
pounding in the ears
restlessness
severe constipation
severe vomiting
shivering
sweating
talking or acting with excitement you cannot control
tightness in the chest
unusual tiredness or weakness
vomiting
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Cold, clammy skin
drowsiness that is so severe you are not able to answer when spoken to or, if asleep, cannot be awakened
pinpoint (small) pupils in the eyes
seizures
slow heartbeat
very slow or troubled breathing
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
feeling of constant movement of self or surroundings
feeling of crawling, tingling, or burning of the skin
lack or loss of strength
memory loss
sensation of spinning
unusual dreams
Rare
Abnormal ejaculation
decreased interest in sexual intercourse
decreased sexual performance or desire
inability to have or keep an erection
loss in sexual ability, desire, drive, or performance
muscle twitching
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
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