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Last reviewed on RxList: 4/18/2017
Ionsys Side Effects Center

Last reviewed on RxList 04/19/2017

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,
  • headache,
  • low blood pressure (hypotension),
  • anemia, or
  • skin reactions where the patch or device was worn (itching, blistering, redness, or swelling).

Tell your doctor if you have serious side effects of Ionsys (fentanyl hydrochloride) including:

  • weak or shallow breathing,
  • severe weakness,
  • lightheadedness or fainting,
  • cold/clammy skin,
  • pale skin, or
  • easy bruising or bleeding.

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.

Ionsys Consumer Information

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)

Ionsys Professional Information


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 1.

Table 1: 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 1.

Other Adverse Reactions

Other adverse reactions that were reported (excluding adverse reactions listed in Table 1) 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.

Post Marketing 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.

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.

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: Anaphylaxis has been reported with ingredients contained in IONSYS.

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

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

Related Resources for Ionsys

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

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