Halothane Theophylline

The following agents may be affected by theophylline Benzodiazepines, -agonists, halothane, ketamine, lithium, nondepolarizing muscle relaxants, propofol, ranitidine, and tetracyclines. Probenecid may increase the effects of dyphylline. 

Peracchia C Effects of the anesthetics heptanol, halothane and isoflurane on gap junction conductance in crayfish septate axons A calcium- and hydrogen-independent phenomenon potentiated by caffeine and theophylline, and inhibited by 4-aminopyridine. J Membr Biol 1991b 121 67-78. 

Metaproterenol (Alupent, Metaprel) [Bronchodilator/ Beta-Adrenergic Agonist] Uses Asthma reversible bronchospasm Action Sympathomimetic bronchodilator Dose Adults. Neb 0.2-0.3 mL in 2.5-3.0 mL of NS Peds. Neb 0.1-0.2 mL/kg of a 5% soln in 2.5 mL NS Caution [C, /-] Contra Tach, other arrhythmias Disp Aerosol 0.65 mg/inhal soln for inhal 0.4, 0.6% tabs 10, 20 mg syrup 10 mg/5 mL SE Nervousness, tremors (common), tach, HTN Interactions T Effects W/ sympathomimetic drugs, xanthines T risk of arrhythmias W/ cardiac glycosides, halothane, levodopa, theophylline, thyroid hormones T HTN W/ MAOIs effects W/ BBs EMS Separate additional aerosol use by 5 min fewer 3i effects than isoproterenol longer-acting monitor lung sounds before/after administration... 

INHALATIONAL- HALOTHANE TERBUTALINE, THEOPHYLLINE Cases of arrhythmias when these bronchodilators are co-administered with halothane Possibly due to sensitization of the myocardium to circulating catecholamines by the volatile anaesthetics to varying degrees Risk of cardiac events is higher with halothane. Desflurane is irritant to the upper respiratory tract, and t secretions can occur and are best avoided in patients with bronchial asthma. Sevoflurane is non-irritant and unlikely to cause serious adverse effects... 

In addition to pharmacokinetic drug-drug interactions, pharmacodynamic effects have been reported as well. Halothane increases the susceptibility to ventricular arrhythmias under theophylline therapy as a result of increased sensitivity of the myocardium to endogenous catecholamine release by theophylUne. Ketamine lowers the theophyUine seizure threshold. Benzodiazepines Uke midazolam, diazepam, lorazepam, and Uurazepam increase the central nervous system concentration of adenosine, a potent central nervous system depressant. As theophyUine also blocks adenosine receptors, it counteracts benzodiazepine-induced sedation, resulting in increased dosage requirements for these compounds. ... 

A number of reports describe arrhythmias apparently due to an interaction between halothane and theophylline or aminophylline. One describes intraoperative arrhythmias in three out of 45 adult asthmatics who had received preoperative theophylline or aminophylline then halothane... 

Over a period of 9 years, tachycardia and extensor-type seizures were observed in 4 patients taking theophylline or aminophylline, who were initially anaesthetised with ketamine, and later with halothane or enllurane." Based on subsequent study in mice, the authors attributed the seizures to an interaction between ketamine and theophylline or aminophylline, and they suggest that the combination should perhaps be avoided in some, or antiseizure premedication be given to patients at risk. However, these cases come from one isolated report. Note that, in mice, ketamine had no effect on aminophylline-induced seizures. ... 

Richards W, Thompson J, Lewis G, Levy DS, Church JA. Cardiac arrest associated with halothane anesthesia in a patient receiving theophylline. (1988) 61, 83-4... 

Zimmerman BL. Arrhythmogenicity of theophylline and halothane used in combination. esth Analg 919) 58, 259-60. 

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