November 30, 2015
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Discontinued Warning IconPlease Note: This Brand Name drug is no longer available in the US.
(Generic versions may still be available.)

Ionsys Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 9/4/2015

Ionsys (fentanyl hydrochloride) Patch is a narcotic (opioid) pain medicine used to treat acute pain after surgery. The brand name Ionsys is discontinued, but generic versions may be available. Common side effects of Ionsys (fentanyl hydrochloride) include nausea, vomiting, stomach pain, constipation, gas, dizziness, drowsiness, anxiety, sleep problems (insomnia), muscle stiffness, back pain, increased sweating, urinating less than usual, or skin reactions where the patch or device was worn (itching, blistering, redness, or swelling).

Ionsys provides a 40 mcg dose of fentanyl per activation on-demand. Ionsys may interact with other medicines that make you sleepy (such as cold medicine, other pain medicine, muscle relaxers, and medicine for depression or anxiety), carbamazepine, phenytoin, diltiazem, St. John's wort, rifampin, antibiotics, antifungal medications, or HIV/AIDS medicines. Tell your doctor all medications and supplements you use. Ionsys may be harmful to a fetus, and could cause addiction or withdrawal symptoms in a newborn. Tell your doctor if you are pregnant or plan to become pregnant during treatment. This drug may also cause addiction and withdrawal symptoms in a nursing infant. Consult your doctor before breastfeeding. Withdrawal symptoms may occur if you suddenly stop taking this medication.

Our Ionsys (fentanyl hydrochloride) Patch 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.

Ionsys 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.

Tell your caregivers right away if you have any of these serious side effects:

  • weak, shallow breathing;
  • severe weakness, feeling light-headed or fainting;
  • cold, clammy skin; or
  • pale skin, easy bruising or bleeding.

Less serious side effects may include:

  • nausea, vomiting, stomach pain, constipation, gas;
  • dizziness, drowsiness, anxiety, sleep problems (insomnia);
  • muscle stiffness, back pain;
  • itching, blistering, redness, or swelling where the patch or device was worn; or
  • increased sweating, urinating less than usual.

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 Ionsys (Fentanyl Iontophoretic Transdermal System)

What is Prescribing information?

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

Ionsys FDA Prescribing Information: Side Effects
(Adverse Reactions)


The following serious adverse reactions are described elsewhere in the labeling:

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.

In controlled and uncontrolled studies, the safety of IONSYS 40 mcg was evaluated in a total of 2114 patients with acute postoperative pain requiring opioid analgesia.

The most common adverse reactions ( ≥ 2%) in the placebo-controlled studies, regardless of relationship to study medication, are listed in Table 3.

Table 3: Adverse Reactions with Incidence ≥ 2% in Placebo-controlled Studies 1, 2, and 3 (N=791; 24 Hour Duration)

Adverse Reactions IONSYS
Body as a Whole
  Headache 9% 7%
Cardiovascular System
  Hypotension 2% <1%
Digestive System
  Nausea 39% 22%
  Vomiting 12% 6%
Hemic and Lymphatic System
  Anemia 3% <1%
Nervous System
  Dizziness 3% 1%
Skin System
  Application site reaction- Erythema 14% 2%
  Pruritus 6% <1%
Urogenital System
  Urinary retention 3% <1%
NOTE: Patients reported as having “Nausea and vomiting” are included in “Nausea” and Vomiting” in Table 3.

Other Adverse Reactions

Other adverse reactions that were reported (excluding adverse reactions listed in Table 3) in 4 active comparator trials vs. IV PCA morphine in patients treated with IONSYS (n=1288), are described below:

Body as a Whole: abdominal pain, back pain, extremity pain, chest pain, chills, abdomen enlarged, asthenia, abscess, hypothermia

Cardiovascular System: syncope, postural hypotension, vasodilation, hypertension, atrial fibrillation, bradycardia, tachycardia, bigeminy, arrhythmia, myocardial infarct

Digestive System: constipation, flatulence, dyspepsia, ileus, dry mouth, diarrhea

Metabolic and Nutritional System: peripheral edema, healing abnormal, edema, dehydration

Musculoskeletal System: leg cramps and myalgia

Nervous System: insomnia, anxiety, somnolence, confusion, paresthesia, hypesthesia, nervousness, agitation, abnormal dreams, tremor

Respiratory System: hypoxia, hypoventilation, dyspnea, apnea, cough increased, asthma, hiccup, atelectasis, rhinitis, hyperventilation

Skin System: application site reactions including: itching, vesicles, papules/pustules, edema, pain, burning, dry and flaky skin, and vesiculobullous rash wound site oozing/bleeding, wound site inflammation/erythema, rash, sweating

Special Senses: abnormal vision-blurred vision

Urogenital System: urination impaired, hematuria, urinary tract infection, urinary urgency, dysuria

Scheduled observation of the skin approximately 24 hours after IONSYS removal was included in several studies. Some redness at the skin sites was observed in approximately 60% of patients at this observation. The skin findings included erythema, edema, and papules. The majority of these events were categorized as mild. Two patients were noted to have hyperpigmentation lasting 2 - 3 weeks at the application site. Three patients noted a rectangular mark at the application site, which persisted for up to 3 months after study completion.

Postmarketing Experience

The following adverse reactions have been identified during post approval use of IONSYS. 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.

The most commonly observed events were related to application site reactions which included urticaria, application site discharge, erosion, hyperesthesia, pustules, rash and scab, application site bleeding, application site infection, and necrosis.

Read the entire FDA prescribing information for Ionsys (Fentanyl Iontophoretic Transdermal System)

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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