Isoflurane (Inhalation)

Inhaled isoflurane is used to cause general anesthesia (loss of consciousness) before and during surgery. It belongs to the group of medicines known as general anesthetics.

This medicine is to be given only by or under the direct supervision of a doctor.

Your doctor will monitor you closely after you receive this medicine. This will help your doctor see if the medicine is working correctly. Blood and urine tests may be needed to check for side effects.

Hyperkalemia may happen rarely after receiving this medicine. Tell your doctor immediately if you experience confusion, an irregular heartbeat, nausea or vomiting, numbness or tingling in your hands, feet, or legs, or trouble breathing after receiving this medicine.

This medicine may cause malignant hyperthermia (a high body temperature). Contact your doctor right away if you experience a fast heartbeat, high fever, or stiff muscles.

Contact your doctor immediately if you notice black, tarry stools, chills, dark urine, dizziness, fever, general tiredness or weakness, headache, itching, light-colored stools, loss of appetite, nausea and vomiting, pain in the upper right part of your stomach, vomiting blood, or yellowing of your eyes and skin. These may be signs of a serious liver issue.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and requires immediate medical attention. Contact your doctor right away if you experience chest tightness, cough, difficulty swallowing, dizziness, fast heartbeat, hives, itching, swelling around the eyelids, face, lips, or tongue, skin rash, trouble breathing, or unusual tiredness or weakness.

Contact your doctor right away if you notice any changes in your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you have a history of heart rhythm issues, including QT prolongation.

General anesthetics may cause some people to feel drowsy, tired, or weak. They may also affect coordination and thinking ability. Therefore, for about 24 hours (or longer if needed) after receiving a general anesthetic, do not drive, operate machines, or do anything else that could be dangerous if you are not alert.

Do not take other medicines unless you have discussed them with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

In deciding to use a medicine, you need to consider the risks and benefits together with your doctor. For this medicine, think about the following:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also inform your healthcare professional about any other allergies you may have, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Studies done so far have not shown any specific problems that would limit the use of inhaled isoflurane in children. However, children are more likely to experience unwanted side effects, including brain or nerve issues, so caution is advised when using this medicine in these patients.

Geriatric

There is no information available on how age affects the use of inhaled isoflurane in older patients.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medication while breastfeeding. Weigh the potential benefits against the potential risks before using this medication while breastfeeding.

Interactions with Medicines

Some medicines should not be used together at all, while in other cases, two different medicines may be used together even if an interaction might happen. In these situations, your doctor may need to adjust the dose or take other precautions. It is especially important for your healthcare professional to know if you are taking any of the medicines listed below when receiving this medicine. The following interactions have been chosen based on their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be necessary in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you take one or both of the medicines.

• Acecainide
• Ajmaline
• Alfentanil
• Alprazolam
• Amiodarone
• Amitriptyline
• Amoxapine
• Aprindine
• Arsenic Trioxide
• Astemizole
• Atracurium
• Azimilide
• Benzhydrocodone
• Bretylium
• Bromazepam
• Buprenorphine
• Bupropion
• Butorphanol
• Calcium Oxybate
• Cannabidiol
• Cannabis
• Cetirizine
• Chloral Hydrate
• Chloroquine
• Chlorpromazine
• Cisatracurium
• Clarithromycin
• Clobazam
• Clonazepam
• Codeine
• Daridorexant
• Desipramine
• Dexmedetomidine
• Dexmethylphenidate
• Dibenzepin
• Dihydrocodeine
• Disopyramide
• Dofetilide
• Dolasetron
• Doxacurium
• Doxepin
• Doxylamine
• Dronedarone
• Droperidol
• Encainide
• Erythromycin
• Esketamine
• Fentanyl
• Flecainide
• Flibanserin
• Fluconazole
• Fluoxetine
• Foscarnet
• Gabapentin
• Gabapentin Enacarbil
• Halofantrine
• Hydrocodone
• Hydromorphone
• Hydroquinidine
• Ibutilide
• Imipramine
• Isradipine
• Ketamine
• Lacosamide
• Lemborexant
• Levocetirizine
• Levomethadyl
• Levorphanol
• Lidoflazine
• Lofexidine
• Lorcainide
• Loxapine
• Magnesium Oxybate
• Mefloquine
• Meperidine
• Methadone
• Methylphenidate
• Metoclopramide
• Mivacurium
• Morphine
• Morphine Sulfate Liposome
• Nalbuphine
• Norepinephrine
• Nortriptyline
• Octreotide
• Olanzapine
• Ondansetron
• Oxycodone
• Oxymorphone
• Pancuronium
• Pentamidine
• Pentazocine
• Periciazine
• Phenobarbital
• Pipecuronium
• Pirmenol
• Potassium Oxybate
• Prajmaline
• Pregabalin
• Primidone
• Probucol
• Procainamide
• Prochlorperazine
• Propafenone
• Protriptyline
• Quinidine
• Remifentanil
• Remimazolam
• Ropeginterferon Alfa-2b-njft
• Sematilide
• Serdexmethylphenidate
• Sodium Oxybate
• Sotalol
• Spiramycin
• St John's Wort
• Sufentanil
• Sulfamethoxazole
• Tapentadol
• Tedisamil
• Telithromycin
• Topiramate
• Tramadol
• Trifluoperazine
• Trimethoprim
• Trimipramine
• Tubocurarine
• Vecuronium
• Zolpidem
• Zuranolone

Using this medicine with any of the following medicines may increase the risk of certain side effects, but using both drugs may be the best treatment option for you. If both medicines are prescribed together, your doctor may change the dose or how often you take one or both of the medicines.

• Labetalol
• Rocuronium

Interactions with Food/Tobacco/Alcohol

Some medicines should not be used at the same time as eating food or certain types of food due to possible interactions. Using alcohol or tobacco with certain medicines can also cause interactions. Talk with your healthcare professional about using your medicine with food, alcohol, or tobacco.

Other Medical Problems

Having other medical issues may affect how you use this medicine. Be sure to inform your doctor if you have any other medical problems, especially:

• Heart or blood vessel disease (e.g., coronary artery disease) or
• Heart rhythm issues or
• Hyperkalemia (high potassium in the blood) or
• Hypotension (low blood pressure) or
• Hypovolemia (low blood volume) or
• Kidney disease or
• Lung or breathing problems (e.g., respiratory depression)—Use with caution. May worsen these conditions.

• Hereditary issues (e.g., high risk for malignant hyperthermia) or
• Liver disease (e.g., hepatitis caused by isoflurane or similar medicines), moderate or severe, history of—Should not be used in patients with these conditions.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do happen, they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

More common

• Anxiety
• chest tightness
• confusion about 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

Rare

• 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 the 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 with 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

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

• Mood changes
• nightmare

Rare

• 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

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.

In the U.S.

• Forane
• Terrell

In Canada

• Isoflurane
• Isoflurane Usp

Available Dosage Forms:

• Liquid
• Solution

Therapeutic Class: Volatile Liquid

Chemical Class: Haloalkane

A doctor or other trained health professional will give you this medicine in a hospital. You will inhale the medicine through a mask placed over your mouth and nose.