FORANE Liquid for inhalation Ref.[10816] Active ingredients: Isoflurane

Premedication

Premedication should be selected according to the need of the individual patient, taking into account that secretions are weakly stimulated by FORANE, and the heart rate tends to be increased. The use of anticholinergic drugs is a matter of choice.

Inspired Concentration

The concentration of isoflurane being delivered from a vaporizer during anesthesia should be known.

This may be accomplished by using:

a. Vaporizers calibrated specifically for isoflurane;
b. Vaporizers from which delivered flows can be calculated, such as vaporizers delivering a saturated vapor which is then diluted.

The delivered concentration from such a vaporizer may be calculated using the formula:

% isoflurane = 100 P_VF_V / F_T (P_A – P_V)

Where:

P_A = Pressure of atmosphere
P_V = Vapor pressure of isoflurane
F_V = Flow of gas through vaporizer (mL/min)
F_T = Total gas flow (mL/min)

Isoflurane contains no stabilizer. Nothing in the agent alters calibration or operation of these vaporizers.

Induction

Induction with isoflurane in oxygen or in combination with oxygen-nitrous oxide mixtures may produce coughing, breath holding, or laryngospasm. These difficulties may be avoided by the use of a hypnotic dose of an ultra-short-acting barbiturate. Inspired concentrations of 1.5 to 3.0% isoflurane usually produce surgical anesthesia in 7 to 10 minutes.

Maintenance

Surgical levels of anesthesia may be sustained with a 1.0 to 2.5% concentration when nitrous oxide is used concomitantly. An additional 0.5 to 1.0% may be required when isoflurane is given using oxygen alone. If added relaxation is required, supplemental doses of muscle relaxants may be used.

The level of blood pressure during maintenance is an inverse function of isoflurane concentration in the absence of other complicating problems. Excessive decreases may be due to depth of anesthesia and in such instances may be corrected by lightening anesthesia.

In the event of overdosage, or what may appear to be overdosage, the following action should be taken:

Stop drug administration, establish a clear airway, and initiate assisted or controlled ventilation with pure oxygen.

Safety and Handling

Occupational Caution

There is no specific work exposure limit established for FORANE. However, the National Institute for Occupational Safety and Health Administration (NIOSH) recommends that no worker should be exposed at ceiling concentrations greater than 2 ppm of any halogenated anesthetic agent over a sampling period not to exceed one hour.

The predicted effects of acute overexposure by inhalation of FORANE include headache, dizziness or (in extreme cases) unconsciousness. There are no documented adverse effects of chronic exposure to halogenated anesthetic vapors (Waste Anesthetic Gases or WAGs) in the workplace. Although results of some epidemiological studies suggest a link between exposure to halogenated anesthetics and increased health problems (particularly spontaneous abortion), the relationship is not conclusive. Since exposure to WAGs is one possible factor in the findings for these studies, operating room personnel, and pregnant women in particular, should minimize exposure. Precautions include adequate general ventilation in the operating room, the use of a well-designed and well-maintained scavenging system, work practices to minimize leaks and spills while the anesthetic agent is in use, and routine equipment maintenance to minimize leaks.

Storage

Store at room temperature 15°-30°C (59°-86°F). Isoflurane contains no additives and has been demonstrated to be stable at room temperature for periods in excess of five years.