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Isoflurane Side Effects

Medically reviewed by Last updated on Dec 18, 2022.

Applies to isoflurane: inhalation liquid, inhalation solution.

Serious side effects of Isoflurane

Along with its needed effects, isoflurane 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 or nurse immediately if any of the following side effects occur while taking isoflurane:

More common

  • Anxiety
  • chest tightness
  • confusion as to time, place, or person
  • cough
  • dry mouth
  • irregular heartbeat
  • irritability
  • seeing, hearing, or feeling things that are not there
  • shaking
  • trouble breathing
  • trouble sleeping
  • unusual excitement, nervousness, or restlessness

Less common

  • Fainting
  • fast or pounding heartbeat or pulse


  • Blurred vision
  • confusion
  • dizziness, faintness. or lightheadedness when getting up suddenly from a lying or sitting position
  • headache
  • pounding in the ears
  • seizures
  • sweating
  • unusual tiredness or weakness

Incidence not known

  • Black, tarry stools
  • bloating
  • bloody urine
  • bluish lips or skin
  • bulging soft spot on head of an infant
  • change in ability to see colors, especially blue or yellow
  • chest pain or discomfort
  • chills
  • constipation
  • dark urine
  • decreased frequency or amount of urine
  • difficulty swallowing
  • high fever
  • hives, itching, skin rash
  • increased thirst
  • indigestion
  • light-colored stools
  • loss of appetite
  • lower back or side pain
  • muscle twitching or jerking
  • nausea or vomiting
  • nervousness
  • no blood pressure or pulse
  • noisy breathing
  • not breathing
  • numbness or tingling in the hands, feet, or lips
  • pain or discomfort in the arms, jaw, back, or neck
  • pains in the stomach, side, or abdomen, possibly radiating to the back vomiting
  • pale or blue lips, fingernails, or skin
  • problems with movement, walking, or speech
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • rhythmic movement of the muscles
  • rigid muscles
  • slow to respond
  • slurred speech
  • stomach pain
  • stopping of the heart
  • swelling of the face, fingers, or lower legs
  • trouble sleeping
  • unconsciousness
  • uncontrolled eye movements
  • unpleasant breath odor
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • vomiting of blood
  • weakness or heaviness of the legs
  • weight gain
  • yellow eyes or skin

Other side effects of Isoflurane

Some side effects of isoflurane 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

  • Mood changes
  • nightmare


  • Dry heaves

Incidence not known

  • Feeling of warmth
  • red, sore eyes
  • redness of the face, neck, arms and occasionally, upper chest
  • redness of the white part of the eyes or inside of the eyelids

For Healthcare Professionals

Applies to isoflurane: inhalation liquid.


Frequency not reported: Hepatocellular injury, blood bilirubin increased, hepatic enzymes increased

Postmarketing reports: Hepatic necrosis, hepatic failure[Ref]


Frequency not reported: Nausea, vomiting, ileus[Ref]


Very common (10% or more): Coughing

Common (1% to 10%): Laryngospasm

Uncommon (0.1% to 1%): Secretions

Rare (less than 0.1%): Bronchospasm, dyspnea, wheezing, chest discomfort

Frequency not reported: Respiratory depression[Ref]


Frequency not reported: Hyperkalemia, blood glucose increased[Ref]


Frequency not reported: Carboxyhemoglobinemia, hemorrhage, white blood cell count increased[Ref]


Frequency not reported: Anaphylactic reaction, hypersensitivity[Ref]


Frequency not reported: Shivering, chills, myoglobinuria, rhabdomyolysis[Ref]


Frequency not reported: Agitation, delirium, altered mood, mental impairment[Ref]


Frequency not reported: Malignant hyperthermia, fluoride increased, blood cholesterol decreased, blood alkaline phosphatase decreased[Ref]

Nervous system

Frequency not reported: Convulsion[Ref]


Frequency not reported: Blood creatinine increased, blood urea decreased[Ref]


Uncommon (0.1% to 1%): Postoperative hypotension

Rare (less than 0.1%): Postoperative hypertension

Frequency not reported: Hypotension, arrhythmia, bradycardia, cardiac arrest, QT prolonged, tachycardia, torsade de pointes

Postmarketing reports: Cardiac arrest[Ref]


Frequency not reported: Swelling face, contact dermatitis, rash[Ref]


1. "Product Information. Forane (isoflurane)." Baxter Pharmaceutical Products, Inc (2009):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.