Halotano: what is it?

Halothane is a medication widely used to induce general anesthesia.. It is an anesthetic that is administered by inhalation and induces a rapid but mild loss of consciousness. It has a pleasant aroma, is colorless and does not irritate the mucous membranes.

It is used for induction and for the maintenance of anesthesia in all types of surgery and in patients of all ages. However, the mechanism by which inhalation anesthetic drugs produce inhibition of sensation perception and induce unconsciousness is not yet known.

During the 1950s and 1980s it was widely used, both in adult patients and in children. It was synthesized by the scientist C.W. Suckling in 1951 and was first used as an anesthetic in 1956. It replaced the use of other anesthetics of the time such as ether or cyclopropane.

However, the use of halothane was gradually reduced during the 80s by the incorporation to the market of new volatile anesthetic drugs, such as enfluoran and isofluoran. However, although very little is used today in developed countries, its use continues in the veterinary branch in third world countries, since it involves a low cost.

Dosage and method of administration

Nowadays, there are different vaporization systems on the market for the administration of halothane. For example, there is an open, semi-open or closed circuit system. All of them are used interchangeably, since they have been used with good results.

Depending on the population group to which it is to be administered, the doses will vary. In this sense, for adults and the elderly, a concentration of 2-4% of halothane in oxygen / nitrous oxide can be administered in order to induce anesthesia. In the event that the objective is to maintain anesthesia, a halothane concentration of 0.5-2% will be used.

On the other hand, for the administration In the pediatric population, a concentration of 1.5-2% is used for the induction of anesthesia and a concentration of 0.5-2% for its maintenance.

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Contraindications to the use of halothane

This medicine cannot be administered to patients who have suffered at some time malignant hyperthermia. It is also contraindicated in patients who are susceptible to it. In addition, if once the drug is administered, the patient develops a clinical picture of unexplained jaundice and pyrexia, future halothane administrations are also contraindicated.

On the other hand, as regards pregnant and breastfeeding women, not enough studies have been carried out to affirm the safety of this medicine in this type of patients. Thus, it would be wise to avoid general anesthesia with inhalation agents during the onset of pregnancy, except when this situation is inevitable.

As for breastfeeding women, there are also no studies adequately controlled with halothane in this population. However, presence of this medicine has been detected in breast milk, but their effects on infants have not been established.

On the other hand, people who must drive vehicles or use machinery should keep in mind that the ability to do so can be altered after general anesthesia. Despite these contraindications, this anesthetic is has used for more than 30 years without consequences apparent.

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Adverse reactions of halothane

Like all medications on the market, halothane is not exempt from producing a series of adverse effects. We understand as adverse effects all those unwanted and unintended events that can be expected in treatment with a medication.

In this sense, halothane, like other agents of this type, can trigger a hypermetabolic clinical picture of skeletal muscle which ultimately leads to malignant hyperthermia. For this reason it is why its use is contraindicated in patients who have already suffered it.

Between the symptoms that accompany this syndrome we can mention:

  • Hypercapnia
  • Muscular stiffness.
  • Tachycardia.
  • Tachypnea
  • Arrhythmias

As you can see, these are very specific symptoms, so you have to pay attention. As soon as any symptoms appear, treatment with these agents should be discontinued. However, there are also other adverse reactions caused by this medicine, such as nausea and vomiting or liver problems.


Halothane It is an agent that is administered by inhalation in order to induce or maintain general anesthesia. You can ask your doctor or pharmacist any questions you have about this medicine or about the general anesthesia process.