By Medically reviewed by hellodoktor

Generic Name: Forane Brand Name(s): Generics only. No brands available.


What is forane (isoflurane) used for?

Forane is commonly used for  induction and maintenance of general anesthesia. This anesthetic agent can also be used for sedation of ventilated patients in the intensive therapy unit for up to 48 hours.

How should I take forane (isoflurane)?

As with any potent general anesthetic, forane (isoflurane, USP) should only be administered by your doctor.

How do I store forane (isoflurane)?

Forane is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store forane in the bathroom or the freezer. There may be different brands of forane that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush forane down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using forane (isoflurane)?

Forane is cautious in these case:

  • Patients who have sensitivity to isoflurane or other halogenated anesthetics.
  • Patients who have malignant hyperthermia.
  • Isoflurane markedly increases cerebral blood flow at deeper levels of anesthesia.
  • Patients who have increased intracranial pressure. In such cases, hyperventilation may be necessary.
  • Patients who can develop bronchoconstriction since bronchospasm can occur.
  • Isoflurane may cause respiratory depression, which may be augmented by narcotic premedication or other agents causing respiratory depression. Respiration should be supervised and if necessary, assisted.
  • Patients who have perioperative hyperkalemia.
  • This drug affects on ability to frive and use machines.

Is it safe during pregnancy or breastfeeding?


Isoflurane, like other inhalational agents, has relaxant effects on the uterus with the potential risk for uterine bleeding. Clinical judgment should be observed when using isoflurane during obstetric anesthesia. Consideration should be taken to use the lowest possible concentration of isoflurane in obstetrical operations.


It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when isoflurane is administered to a nursing woman.

Side effects

What side effects can occur from forane (isoflurane)?

Some side effects can occur when using this drug, such as:

Potential serious undesirable effects include:

  • Malignant hyperthermia
  • Hyperkalemia
  • Elevated serum creatine kinase
  • Myoglobinuria
  • Cardiac arrest
  • Bronchospasm
  • Laryngospasm
  • Uterine bleeding
  • Shivering
  • Nausea
  • Vomiting
  • Ileus
  • Agitation
  • Hypersensitivity

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.


What drugs may interact with forane (isoflurane)?

Forane may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Products may interact with this drug, including:

  • Muscle relaxants
  • Beta-sympathomimetic agents (isoprenaline)
  • Alpha- and beta-sympathomimetic agents (adrenaline and noradrenaline)
  • Non-Selective MAO-Inhibitors
  • Isoniazide
  • Calcium antagonists
  • Opioids, benzodiazepines and other sedative agents

Does food or alcohol interact with forane (isoflurane)?

Forane may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with forane (isoflurane)?

Forane may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.


The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using forane (isoflurane).

What is the dose of Forane (isoflurane) for an adult?

General anesthesia: 

MAC values for isoflurane diminish with age, falling from an average in oxygen of 1.28% in the mid-twenties to 1.15% in the mid-forties to 1.05% in the mid-sixties age group.


Drugs used for premedication should be selected for the individual patient, bearing in mind the respiratory depressant effect of isoflurane. The use of anticholinergic drugs is a matter of choice.


A short-acting barbiturate or other intravenous induction agent is usually administered followed by inhalation of the isoflurane mixture. Alternatively, isoflurane with oxygen or with an oxygen/nitrous oxide mixture may be used.
It is recommended that induction with isoflurane be initiated at a concentration of 0.5%. Concentrations of 1.5 to 3.0% usually produce surgical anesthesia in seven to ten minutes.


Surgical levels of anesthesia may be maintained with 1.0 to 2.5% isoflurane in oxygen/nitrous oxide mixtures. An additional 0.5 to 1.0% isoflurane may be required when given with oxygen alone. If added relaxation is required, supplemental doses of muscle relaxant may be used.
Arterial pressure levels during maintenance tend to be inversely related to alveolar isoflurane concentrations in the absence of other complicating factors. Excessive falls in blood pressure may be due to depth of anesthesia and, in these circumstances, should be corrected by reducing the inspired isoflurane concentration.


As with other agents, lesser concentrations of isoflurane are normally required to maintain surgical anesthesia in elderly patients.


Sedation may be maintained with 0.1 to 1.0% isoflurane in air/oxygen mixtures. This dose will need to be titrated to the requirements of the individual patients.

What is the dose of forane (isoflurane) for a child?

Isoflurane may be used in neonates and infants under two years of age with an acceptable margin of efficacy and safety and is compatible with all drugs commonly used in anesthetic practice.

General anesthesia: 

For neonates, the MAC of isoflurane in oxygen is 1.6% in infants aged 1 month to 6 months is 1.87%, and from 6 months to 12 months, 1.80%.

How is forane (isoflurane) available?

Forane is available in the following dosage forms and strengths:

  • Liquid for inhalation 100 ml

What should I do in case of an emergency or overdose?

In the event of overdosage, or what may appear to be overdosage, stop drug administration, establish a clear airway and initiate assisted or controlled ventilation with pure oxygen.

Hypotension and respiratory depression have been observed. Close monitoring of blood pressure and respiration is recommended. Supportive measures may be necessary to correct hypotension and respiratory depression resulting from excessively deep levels of anesthesia.

What should I do if I miss a dose?

If you miss a dose of forane, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: February 10, 2017 | Last Modified: September 12, 2019