indication

For the induction and maintenance of general anesthesia

pharmacology

Halothane is a general inhalation anesthetic used for induction and maintenance of general anesthesia. It reduces the blood pressure and frequently decreases the pulse rate and depresses respiration. It induces muscle relaxation and reduces pains sensitivity by altering tissue excitability. It does so by decreasing the extent of gap junction mediated cell-cell coupling and altering the activity of the channels that underlie the action potential.

mechanism of action

Halothane causes general anaethesia due to its actions on multiple ion channels, which ultimately depresses nerve conduction, breathing, cardiac contractility. Its immobilizing effects have been attributed to its binding to potassium channels in cholinergic neurons. Halothane's effect are also likely due to binding to NMDA and calcium channels, causing hyperpolarization.

toxicity

Toxic effects of halothane include malignant hyperthermia and hepatitis.

biotransformation

Halothane is metabolized in the liver, primarily by CYP2E1, and to a lesser extent by CYP3A4 and CYP2A6.

drug interactions

Aminophylline: Increased risk of cardiac arrhythmia

Labetalol: Monitor arterial pressure closely

Oxtriphylline: Increased risk of cardiac arrhythmia

Theophylline: Increased risk of cardiac arrhythmia