Inhalation vapor, liquid
(clear, colorless)

1. What Forene is and what it is used for

Forene contains the active substance isoflurane and is an anesthetic called a general anesthetic. Forene inhales to achieve or maintain the deep anesthesia required during surgery. The drug causes you to lose consciousness and the ability to feel pain during your surgery. It is given by an anesthetist and with the help of a carburetor, the liquid is converted into a gas, so you can inhale it. Forene is only given by healthcare professionals.

Forene can be given to both adults and children.

2. What you need to know before using Forene

You should not get Forene

  • if you have previously been told that you are sensitive or allergic to isoflurane (the active substance in Forene) or other so-called halogenated anesthetics.
  • if you have an established or suspected hereditary predisposition to an unusual type of severe high fever, so-called malignant hyperthermia. Insensitive people, certain anesthetics can affect the skeleton and muscles and lead to an increase in the need for oxygen and body temperature.

Warnings and cautions

Talk to your doctor or nurse before receiving Forene:

  • if you have or have had liver problems, e.g. hepatitis (inflammation of the liver), jaundice, or liver damage.
  • if you have previously been anesthetized with anesthetics similar to Forene, especially if it has happened repeatedly on a short interval. This can lead to a risk of liver damage.
  • if you have or have had an irregular heartbeat and ECG changes associated with it ( QT prolongation) or other effects on heart rate ( Torsade de pointes ). Forene has in some cases been able to cause these.
  • if you have a so-called mitochondrial disease.
  • if you have low blood volume or low blood pressure.
  • if you have elevated pressure in the brain (intracranial pressure).
  • if you have any neuromuscular disease (eg myasthenia gravis or Duchenne muscular dystrophy).
  • if you have easy to get cramps in the trachea because Forene can cause this.

As with other anesthetics, Forene may have a debilitating effect on mental activity for a few days after anesthesia and minor changes in mood for several days after anesthesia.

Other medicines and Forene

Tell your doctor or nurse if you are taking, have recently taken, or might take any other medicines. This is especially important if you are taking the following medicines:

  • Certain antidepressants (so-called non-selective MAO inhibitors ) may increase the risk of serious problems during surgery.
  • Certain cardiac stimulants or bronchodilators ( isoprenaline, adrenaline, and norepinephrine ). Concomitant use can lead to an irregular heartbeat.
  • Ephedrine (bronchodilators and decongestants) and amphetamines (stimulants) can cause a sharp rise in blood pressure.
  • Beta-blockers or calcium channel blockers (used to treat high blood pressure and certain types of heart problems).
  • Isoniazid ( antibiotics for tuberculosis ) may increase the risk of liver damage.
  • Laughing gas
  • Opioid is e.g. codeine or benzodiazepines e.g. zopiclone and diazepam . These medicines are used for an analgesic, antispasmodic or hypnotic effect.

Unite with food, drink, and alcohol

The medical staff will give you instructions regarding food and drink before the operation.

Alcohol can affect the concentration of Unite in the body. If you have any further questions, ask your doctor or pharmacist.

Pregnancy, breastfeeding, and fertility

If you are pregnant or breast-feeding, think you may be pregnant, or are planning to have a baby, ask your doctor for advice before taking this medicine.

Driving and using machines

Do not drive or use machines after you have been given anesthetics until your doctor informs you that it is safe. Your ability to drive or use machines may be impaired for several days.

You are responsible for assessing whether you are fit to drive a motor vehicle or perform work that requires increased attention. One of the factors that can affect your ability in these respects is the use of drugs due to their effects and/or side effects. Descriptions of these effects and side effects can be found in other sections. Read all the information in this leaflet for guidance. If you are not sure, talk to your doctor or pharmacist.

3. How to use Forene

Forene will only be given to you by healthcare professionals. They decide what dose you should receive depending on your age, weight and what type of surgery you should undergo. If you have any further questions, ask your doctor or pharmacist.

Treatment before anesthesia for children

Doctors may decide to give your child medicines to counteract the risk of shortness of breath and the effect on the heart rhythm, which can occur when using Forene.

Anesthesia at the beginning of anesthesia

To fall asleep, you can inhale Forene through a mask, but in most cases, you will first receive an injection of another anesthetic before you receive Forene. Forene is not recommended for infants and children for anesthesia at the beginning of anesthesia.

Maintain sleep during anesthesia

During the operation, you will continue to inhale Forene through a mask. You or your child will be supervised by healthcare professionals.

Waking up after the anesthesia

After your healthcare provider stops you inhaling Forene, you will wake up within minutes.

If you use more Forene than you should 

Because Forene is given under strict supervision and dosed individually, it is unlikely that you will receive too much. If you get too much Forene, your anesthetist will take the necessary steps.

If you have any further questions on the use of this product, ask your doctor or pharmacist.

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them. Side effects can occur both during and after your surgery. Any side effects that occur during your surgery will be managed by your doctor.

Some side effects can be serious. If you or your child experience any unusual or unexpected symptoms after surgery, tell a doctor IMMEDIATELY or go to the nearest emergency room.

  • Very high and rapid temperature rise ( malignant hyperthermia ) also with possible symptoms such as muscle stiffness, palpitations, rapid breathing, irregular heartbeat, and blood pressure.
  • A special type of irregular heartbeat and ECG changes associated with it ( QT prolongation) or other effects on the heart rhythm ( Torsade de pointes ).
  • Inflammation or damage to the liver or liver cells. People with liver disease may have pain or a feeling of bloating in the stomach, dark urine, pale or white stools, fatigueitching, yellow (due to elevated bilirubin in the blood) eyes, nausea, and vomiting.
  • Seizures
  • Severe allergic reaction or hypersensitivity reaction with symptoms such as rash, swelling of the face, wheezing, shortness of breath, chest discomfort.
  • Severe muscle damage with symptoms such as unexplained muscle pain, muscle cramps, or muscle weakness ( rhabdomyolysis ).
  • Tarmvred
  • Cardiac arrest

The above side effects occur in an unknown number of users.

The most common side effects that have been reported are:

  • Contraction of the lungs and airways makes it difficult to breathe
  • Increased levels of sugar and potassium in the blood. In rare cases, abnormal heart rhythms ( arrhythmia ) and deaths have been reported shortly after surgery in children who have inhaled anesthetics.

Other side effects that have been reported during and after surgery (affects unknown users):

  • Abnormally slow or fast heartbeat
  • Irregular heartbeat
  • Shortness of breath, wheezing, impaired breathing
  • Anxiety or upset
  • Confusion
  • Mood swings
  • EEC change (measurement of brain activity)
  • Reducing effect on thought activity
  • Low blood pressure
  • Uterine bleeding (during abortion)
  • Nausea, vomiting
  • Overindulge
  • Abnormal liver or kidney function tests (eg certain liver enzymes, bilirubin, alkaline phosphatase and creatinine, creatinine phosphokinase, and urea in the blood)
  • Elevated white blood cell count
  • Elevated fluoride level in the blood *
  • Elevated levels of certain blood proteins (carboxyhemoglobin)
  • Lowered cholesterol in the blood

* Levels of fluoride in the blood may increase slightly during and immediately after anesthesia due to the body breaking down Forene, but these levels are not thought to be harmful and will soon return to normal values.


Throat cramps are slightly more common in children than in adults.

There are reports that, in rare cases, the irregular heartbeat may occur in children after surgery with this type of anesthetic. This is due to altered potassium levels in the blood and can be life-threatening.

5. How to store Forene

Do not store above 25 ° C. Store in the original package. Close the package tightly. Sensitive to light.

Do not use this medicine after the expiry date which is stated on the label.

6. Contents of the packaging and other information

Content declaration

The active substance is isoflurane.

No other ingredients.

What the medicine looks like and contents of the pack

Forene is a liquid that is delivered in a 250 ml brown glass bottle.

Marketing Authorisation Holder:

AbbVie AB

Box 1523

171 29 Solna


Aesica Queenborough Limited


Kent ME11 5EL


Muhammad Nadeem

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