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Terrell can be given to induce and maintain general anesthesia. There isn't enough evidence yet to support its use in obstetric (childbirth-related) anesthesia.
Pharmacology
Isoflurane is a nonflammable liquid and a general inhalation anesthetic drug. Induction of and recovery from isoflurane anesthesia are rapid. Isoflurane has a mild pungency, which limits the rate of induction, although excessive salivation or tracheobronchial secretions do not appear to be stimulated. Pharyngeal and laryngeal reflexes are readily obtunded.
Isoflurane is a profound respiratory depressant. As the anesthetic dose is increased, tidal volume decreases and respiratory rate is unchanged. This depression is partially reversed by surgical stimulation, even at deeper levels of anesthesia. Isoflurane evokes a sigh response reminiscent of that seen with diethyl ether and enflurane, although the frequency is less than with enflurane.
Blood pressure decreases with induction of anesthesia but returns toward normal with surgical stimulation. Progressive increases in depth of anesthesia produce corresponding decreases in blood pressure. Nitrous oxide reduces the inspiratory concentration of isoflurane needed to reach a desired level of anesthesia, and it may lessen the arterial hypotension seen with isoflurane alone.
With controlled ventilation and normal PaC02, cardiac output is maintained despite increasing depth of anesthesia. This happens mainly because heart rate rises and compensates for a fall in stroke volume. The hypercapnia that comes with spontaneous ventilation during isoflurane anesthesia pushes heart rate up further and raises cardiac output above awake levels.
All commonly used muscle relaxants are markedly potentiated with isoflurane, and the effect is most profound with the nondepolarizing type. Neostigmine reverses the effect of nondepolarizing muscle relaxants in the presence of isoflurane. All commonly used muscle relaxants are compatible with isoflurane.
Dosage Reference
Reference Information Only
Dosages shown are general references from official sources. Always consult your doctor or pharmacist for personalized dosing.
Adults:
Route of administration: Isoflurane should be given by inhalation, delivered from a vaporizer designed specifically for use with isoflurane, and only by persons trained in administering general anesthesia. Facilities for maintaining a patent airway, providing artificial ventilation, enriching oxygen, and supporting circulatory resuscitation must be immediately available. The minimum alveolar concentration (MAC) of isoflurane decreases as the patient's age increases.
Premedication: Premedication should be chosen according to the individual patient's needs, bearing in mind that isoflurane only weakly stimulates secretions and tends to increase heart rate.
Induction: Inducing anesthesia with isoflurane in oxygen, or in combination with oxygen nitrous oxide mixtures, may cause coughing, breath holding, laryngospasm and bronchospasm, and these effects increase with the concentration of isoflurane used. Giving a hypnotic dose of an ultra short acting barbiturate can help avoid these difficulties. Inspired concentrations of 1.5 to 3.0% isoflurane usually produce surgical anesthesia within 7 to 10 minutes.
Surgical levels of anesthesia can be maintained with a concentration of 1.0 to 2.5% when nitrous oxide is used alongside isoflurane. An additional 0.5 to 1.0% may be needed when isoflurane is given with oxygen alone. If further muscle relaxation is needed, supplemental doses of muscle relaxants may be used. During maintenance, blood pressure tends to fall as the isoflurane concentration rises, provided no other complications are present. Excessive drops in blood pressure may result from anesthesia being too deep, and in such cases can be corrected by lightening the anesthesia.
Side Effects
The most common side effects include delirium, agitation, breath holding, cough, laryngospasm, nausea, vomiting, chills/shivering and nodal arrhythmia.
Cautions & Contraindications
Warnings & Precautions
Rare rises in serum potassium have been linked to inhaled anesthetics. In children during the period after surgery, these rises have sometimes led to heart rhythm problems and death. In people who are susceptible, Terrell may trigger malignant hyperthermia, a condition in which the skeletal muscles go into a hypermetabolic state and need a great deal of oxygen. If malignant hyperthermia is suspected, stop all agents that could trigger it, give dantrolene sodium by the intravenous route, and start supportive treatment. Mild, moderate and severe liver dysfunction or hepatitis after surgery, with or without jaundice, has been reported with Terrell. Some of these cases involved fatal liver necrosis and liver failure. Terrell can also prolong the QTc interval, and rare cases of torsade de pointes have been reported. In susceptible patients, the QT interval should be monitored when Terrell is given. Every patient under Terrell anesthesia needs continuous monitoring. Breathing should be watched closely, and assisted or controlled ventilation should be used when needed. Keeping blood pressure and circulation normal matters a great deal in patients with coronary artery disease, since it helps prevent myocardial ischaemia. In these patients, extra cardiac monitoring may be considered if clinically needed. Choosing the dose calls for particular care in patients who are hypovolaemic, hypotensive or otherwise haemodynamically compromised, for example because of other medicines they are taking. In patients who have, or are at risk of, raised intracranial pressure (ICP), Terrell should be given together with measures that lower ICP, as clinically appropriate. If the clinician suspects that the CO2 absorbent may be dried out, it should be replaced before Terrell is given. Like other general anesthetics, Terrell may cause a slight drop in intellectual function for 2 or 3 days after anesthesia.
Contraindications
Isoflurane should not be used in anyone who is hypersensitive to isoflurane, to other halogenated anesthetic agents, or to any other ingredient in the product, or in anyone for whom general anesthesia itself is contraindicated. It should also be avoided in patients with a known or suspected genetic susceptibility to malignant hyperthermia, and in those with a history of confirmed hepatitis linked to a halogenated inhalational anesthetic, or a history of unexplained moderate-to-severe liver dysfunction (such as jaundice accompanied by fever and/or eosinophilia) following anesthesia with isoflurane or another halogenated inhalational anesthetic.
Pregnancy & Breastfeeding
Isoflurane hasn't been studied thoroughly in well-designed trials involving pregnant women. It also isn't clear how much isoflurane passes into breast milk, so before giving it to a breastfeeding mother, the likely benefits should be weighed against any possible risks to her baby on an individual basis.
⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
Use in Special Populations
Use in children and adolescents
Studies in young children suggest that repeated or prolonged use of general anesthetic or sedation drugs, Isoflurane included, in children younger than 3 years may have negative effects on their developing brains. When a procedure needing anesthesia is elective, the timing in a child should be decided by weighing the benefits of the procedure against the possible risks.
Overdose
If someone receives too much Isoflurane, the first step is to stop giving the drug. Then clear the airway and start assisted or controlled ventilation using pure oxygen. Keep watching cardiovascular function, and treat any signs of poor end-organ perfusion as the clinical situation requires.
⚠️ In an emergency call 999 or go to the nearest hospital emergency department.
Storage
Keep Isoflurane below 25°C in a dry place and away from light. Make sure children cannot reach it.
Drug Interactions
Common questions about Terrell 100%
What is Terrell 100% Nebuliser Solution?
Terrell 100% Nebuliser Solution is a medicine that contains Isoflurane. It is made by ZAS Corporation. It belongs to the General (Inhalation) anesthetics group of medicines.
What is Terrell used for?
Terrell can be given to induce and maintain general anesthesia. There isn't enough evidence yet to support its use in obstetric (childbirth-related) anesthesia.
What are the side effects of Terrell?
The most common side effects include delirium, agitation, breath holding, cough, laryngospasm, nausea, vomiting, chills/shivering and nodal arrhythmia.
Can I take Terrell during pregnancy or while breastfeeding?
Isoflurane hasn't been studied thoroughly in well-designed trials involving pregnant women. It also isn't clear how much isoflurane passes into breast milk, so before giving it to a breastfeeding mother, the likely benefits should be weighed against any possible risks to her baby on an individual basis. Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
What happens if I take too much Terrell?
If someone receives too much Isoflurane, the first step is to stop giving the drug. Then clear the airway and start assisted or controlled ventilation using pure oxygen. In an emergency call 999 or go to the nearest hospital emergency department.
How should I store Terrell?
Keep Isoflurane below 25°C in a dry place and away from light. Make sure children cannot reach it.
Can I take other medicines with Terrell?
Some medicines can interact with Isoflurane, for example: Fentanyl, Nitrous Oxide, Vecuronium Bromide, Atracurium Besilate, Rocuronium Bromide, Pancuronium Bromide. Tell your doctor or pharmacist about every medicine you take.
Do I need a prescription for Terrell?
Terrell is a prescription (Rx) medicine. Take it as your doctor advises.