Halothane Pancuronium

The use of both halothane and pancuronium in patients taking tricyclic antidepressant has been reported as resulting in severe tachydysrhythmias. Experiments in dogs have shown that this combination can produce ventricular fibrillation and cardiac arrest (192). Enflurane also resulted in tachycardias in dogs given both imipramine and pancuronium acutely, but not when the imipramine was given chronically for 15 days beforehand. Pancuronium should not be used in patients taking tricyclic antidepressants. 

Edwards RP, Miller RD, Roizen MF, Ham J, Way WL, Lake CR, Roderick L. Cardiac responses to imipramine and pancuronium during anesthesia with halothane or enflurane. Anesthesiology 1979 50(5) 421-5. 

Muscle relaxants may also contribute to anesthesia. Pancuronium 0.1 mg/kg has been reported to lower the MAC for halothane by 25% (135). It was conjectured that this could be due to a central effect or peripheral effect, through reduction of afferent input from muscle spindles to the reticular activating system. Recently, however, a similar though not identical study (SEDA-15, 124) (136) failed to confirm that pancuronium, vecuronium, or atracurium lowers the MAC for halothane. 

Miller RD, Way WL, Dolan WM, Stevens WC, Eger El 2nd. The dependence of pancuronium- and d-tubocurarine-induced neuromuscular blockades on alveolar concentrations of halothane and forane. Anesthesiology 1972 37(6) 573-81. 

Cardiovascular adverse effects are minimal with pancuronium. Ganglion blockade does not occur. Shght dose-dependent rises in heart rate, blood pressure, and cardiac output are common (5), but are often masked by the actions of other co-administered agents, such as fentanyl or halothane, which cause bradycardia or hypotension. These adverse effects of pancuronium are thus often beneficial and can be deliberately harnessed. Several mechanisms contribute vagal blockade via selective blockade of cardiac muscarinic receptors (6), release of noradrenaline from adrenergic nerve endings (7), increased blood catecholamine concentrations (8), inhibition of neuronal catecholamine reuptake (9-11), and direct effects on myocardial contractility (12). These have been reviewed (13-15). 

Pancuronium is relatively contraindicated, particularly in combination with halothane, in patients who may have raised catecholamine concentrations, or who are receiving drugs with sympathomimetic effects. Severe hypertension together with tachycardia can occur when pancuronium is given to a patient with a pheochromocytoma (34,35). 

Halothane anesthesia increases the risks of tachydys-rhythmias when pancuronium is used (47). 

Forbes AR, Cohen NH, Eger El 2nd. Pancuronium reduces halothane requirement in man. Anesth Analg 1979 58(6) 497-9. 

Fahey MR, Sessler DI, Cannon JE, Brady K, Stoen R, Miller RD. Atracurium, vecuronium, and pancuronium do not alter the minimum alveolar concentration of halothane in humans. Anesthesiology 1989 71(l) 53-6. 

Katz RL. Modification of the action of pancuronium by succinylcholine and halothane. Anesthesiology 1971 35(6) 602-6. 

Pancuronium is reported to lower the MAC for halothane, but whether this is a central or peripheral action is not known. 

Gregoretti SM, Sohn YJ, Sia RL. Heart rate and blood pressure changes after ORG NC45 (vecuronium) and pancuronium during halothane and enflurane anesthesia. Anesthesiology 1982 56(5) 392-5. 

Clinically important, potentially hazardous interactions with acetazolamide, aminoglycosides, anticholinesterases, bambuterol, calcium channel blockers, chloroquine, chlorpromazine, clindamycin, d-pencillamine, ecothiophate iodine, enflurane, furosemide, halothane, hexomethonium, isoflurane, ketamine, lidocaine, lincomycin, lithium salts, magnesium salts, mannitol, MAO inhibitors, organophosphates, pancuronium, phenytoin, polymyxins, procainamide, quinidine, sevoflurane, spectinomycin, tetracyclines... 

Anesthesia with halothane causes some relaxation by central depression in addition, the duration and magnitude of the muscular relaxation induced by nondepolarizing skeletal muscle relaxants such as tubocurarine or pancuronium are increased (see also Figure 99). 

Electrolyte imbalance, and diseases that lead to electrolyte imbalance, such as adrenal cortical insufficiency, alter neuromuscular blockade. Depending on the nature of the imbalance, either enhancement or inhibition may be expected. Magnesium sulfate, used in the management of toxemia of pregnancy, enhances the skeletal-muscle-relaxing effects of pancuronium. Antibiotics such as aminoglycosides, tetracyclines, clindamycin, lincomycin, colistin, and sodium colistimethate augment the pancuronium-induced neuromuscular blockade. Anesthetics such as halothane, enflurane, and isoflurane enhance the action of pancuronium, whereas azathioprine will cause a reversal of neuromuscular blockade. 

Interestingly, anticholinesterases, ACH and ion antagonize competitively pancuronium bromide effectively however, its activity is virtually enhanced by general anaesthetics, for instance halothane, ether, enflurane etc. (see Chapter 4). Therefore, the latter substantial potentiation in pharmacological activity is particularly useful to the anaesthetist due to the faet that it is administered invariably as an adjunct to the anaesthetic procedure in order to cause simultaneous relaxation of the skeletal muscle. 

E. Dysrhythmias are possible with myocardial sensitizers (eg, halothane) and sympathethic stimulating agents (eg, pancuronium). 

In two early studies, halothane was found to shorten the recovery from pancuronium and gallamine. ... 

Barth L. Paradoxical interaction between halothane and pancuronium. Anaesthesia (1973)... 

Cardiac arrhythmias can develop during the concurrent use of halothane and aminophylline but this seems less likely with isoflu-rane. One report attributes seizures to an interaction between ketamine and aminophylline. Supraventricular tachycardia occurred in a patient taking aminophylline when pancuronium was given. Isolated cases suggest that the effects of pancuronium, but not vecuronium, can be opposed by aminophylline. 

Tricyclic antidepressants may increase the risk of arrhythmias and hypotension during anaesthesia. Tachyarrhythmias have been seen in patients taking imipramine who were given halothane and pancuronium. Some very limited evidence su ests that amitriptyline may increase the likelihood of enflurane-induced seizure activity. A man taking maprotiline and lithium developed a tonic-clonic seizure when given propofol. Tricyclics may cause an increase in the duration of barbiturate anaesthesia and lower doses of barbiturates may be required. 

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