Cardiac rate and rhythm changes with atropine and methscopolamine

Abstract

The effects of methscopolamine bromide (MSB) and atropine were compared in patients prior to elective surgery. After administration of the second dose of MSB (total dose 1.5 mug/kg) all patients exhibited at least 20% increase in heart rate. In contrast, three doses of atropine (total dose 5.3 mug/kg) were required for most patients to attain a 20% increase in heart rate while 2 patients did not attain this heart rate with a dose of 10.6 mug/kg of atropine. Comparison if single injections of MSB and atropine in normal subjects also demonstrated a more reliable dose-response relationship with MSB. Electrocardiographic changes recorded were typical of those reported with anticholinergic agents. Sinus and atrial arrhythmias were more common with atropine and nodal arrhythmias and conduction disturbances were more common with MSB. This study demonstrated that MSB can be reliably substituted for atropine when an anticholinergic drug is needed to increase heart rate. Since MSB has a limited ability to cross the blood-brain barrier, it may be the more desirable drug in patients in whom the central nervous system effects of atropine may be deleterious.

Acute Cardiovascular and Cardiorespiratory Effects of JWH-018 in Awake and Freely Moving Mice: Mechanism of Action and Possible Antidotal Interventions?

“…Beyond the expected effect on HR, atropine was also able to decrease JWH-018-induced tachyarrhythmia, particularly during the last two hours of the experiment. By increasing the heart rate, atropine was effective in reducing ventricular ectopic beats, thus improving cardiac dysrhythmia [71,79]. Moreover, atropine decreases the cardiac automaticity in the S-A node [80], improves A-V nodal conduction, avoiding A-V block, which has often been found after SCs administration [81,82].…”