Indications & Uses
Halosin is a volatile anaesthetic agent suitable for inducing and maintaining anaesthesia across all types of surgery, in patients of any age.
Dosage Reference
Reference Information Only
Dosages shown are general references from official sources. Always consult your doctor or pharmacist for personalized dosing.
Adults:
A number of anaesthetic vaporisers specially designed for use with Halothane are available. Open, semi-open, semi-closed and closed circuit systems have all been used with good results. For induction of anaesthesia, adults may be given a concentration of 2 to 4% Halothane in Oxygen or Nitrous Oxide, while children are usually given a concentration of 1.5 to 2% Halothane in Oxygen or Nitrous Oxide. For maintenance of anaesthesia, adults and children usually require a concentration of 0.5 to 2%, with the lower concentration generally most suitable for elderly patients.
Side Effects
Post-operative nausea, vomiting, and shivering are common. It can also cause respiratory depression, low blood pressure, muscle relaxation, and a slowed heart rate.
Cautions & Contraindications
Warnings & Precautions
Adrenaline should be used with caution in patients anaesthetised with Halosin, since it may bring on dysrhythmias; the dose of adrenaline should therefore be kept low, and a beta-receptor antagonist given if needed. The room should be adequately ventilated when Halosin is used, and the concentration of Halosin in the air should be kept as low as possible. Effect on ability to drive or operate machinery: Patients should be told that skilled tasks such as driving and operating machinery may be performed less well for some time after general anaesthesia. Accidental ingestion: Cases of ingestion should be treated symptomatically. Because Halosin relaxes the uterine muscle, anaesthesia should be kept at the lightest plane possible during obstetric operations. Moderate hyperventilation during neurosurgery is recommended to counter the rise in cerebrospinal fluid pressure that can occur with Halosin. Malignant hyperpyrexia has been reported in some patients receiving Halosin. This syndrome also occurs with other anaesthetic agents and may respond to intravenous dantrolene sodium. During induction of Halosin anaesthesia, a moderate fall in blood pressure commonly occurs. The pressure tends to rise again once the vapour concentration is reduced to maintenance levels, but it usually stays steady below the pre-operative level. This hypotensive effect is useful, as it helps provide a clear operating field and reduces haemorrhage. If needed, however, an intravenous dose of methoxamine, usually 5 mg, can be given to counter the fall in blood pressure. Cardiac arrhythmias have been reported during anaesthesia, and Halosin increases the effect of non-depolarising muscle relaxants. As above, adrenaline should be given with caution to patients anaesthetised with Halosin, since dysrhythmias may be precipitated; the dose of adrenaline should be restricted and a beta-receptor antagonist given if necessary. The room should be adequately ventilated when Halosin is used, and its concentration in the air should be kept as low as possible.
Contraindications
Halothane can cause liver damage, though the incidence of severe liver damage (jaundice, which may progress to hepatic failure as a result of extensive death of liver cells) is unknown. Repeated exposure appears to increase the risk of developing hepatic failure. While short intervals between exposures are more likely to raise the risk of liver toxicity, even long intervals between exposures may not remove the risk, since some patients have developed severe reactions to Halothane given many years after a previous exposure. Based on the information available at present, the following precautions are advised. A careful anaesthetic history should be taken before use, to establish any previous exposure to Halothane and any reactions that followed it. Repeated exposure to Halothane within a period of at least 3 months should be avoided unless there are overriding clinical circumstances. A history of unexplained jaundice and fever in a patient following exposure to Halothane rules out its future use in that patient unless absolutely essential. Patients should be told if they have developed a reaction possibly related to Halothane anaesthesia, and such patients should be given a medical alert card stating the problem.