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Terrell (Inhalation)

Generic name: isofluraneeye-soe-FLOO-rane ]
Drug class: General anesthetics

Medically reviewed by Last updated on Mar 2, 2023.

Uses for Terrell

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.

Before using Terrell

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


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


Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of inhaled isoflurane in children. However, children are more likely to have unwanted side effects, including brain or nerve problems, which may require caution in patients receiving this medicine.


No information is available on the relationship of age to the effects of inhaled isoflurane in geriatric patients.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of 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 required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use 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
  • 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

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

  • Labetalol
  • Rocuronium

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Heart or blood vessel disease (eg, coronary artery disease) or
  • Heart rhythm problems 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 (eg, respiratory depression)—Use with caution. May make these conditions worse.
  • Hereditary problems (eg, high risk for malignant hyperthermia) or
  • Liver disease (eg, hepatitis caused by isoflurane or similar medicines), moderate or severe, history of—Should not be used in patients with these conditions.

Proper use of Terrell

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.

Precautions while using Terrell

Your doctor will check you closely after receiving this medicine. This will allow your doctor to see if the medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

Hyperkalemia may occur rarely after receiving this medicine. Tell your doctor right away if you have confusion, irregular heartbeat, nausea or vomiting, numbness or tingling in the hands, feet, or legs, or trouble breathing after receiving this medicine.

This medicine may cause malignant hyperthermia (high body temperature). Check with your doctor right away if you have fast heartbeat, high fever, or rigid muscles.

Check with your doctor right away if you have black, tarry stools, chills, dark urine, dizziness, fever, general tiredness or weakness, headache, itching, light-colored stools, loss of appetite, nausea and vomiting, upper right stomach pain, vomiting of blood, or yellow eyes and skin. These may be symptoms of a serious liver problem.

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

Contact your doctor right away if you have any changes to 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 had a heart rhythm problem, including QT prolongation.

General anesthetics may cause some people to feel drowsy, tired, or weak. They may also cause problems with coordination and one's ability to think. Therefore, for about 24 hours (or longer if necessary) after receiving a general anesthetic, do not drive, use machines, or do anything else that could be dangerous if you are not alert.

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

Side Effects of Terrell

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 or nurse immediately if any of the following side effects occur:

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

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


  • 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.

Further information

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