Why do we give neostigmine preceded by atropine when we use it in treatment of myasthenia gravis and not in urine retention?
We give neostigmine preceded by atropine in myasthenia gravis to block the muscarinic adverse effects on the heart and don\’t make the patient exposed to arrest fatal cardiac arrest. (Notice that: Atropine blocks only the M-receptors which may lead to arrest but will not block the Nm receptors which are required in the treatment of myasthenia gravis). If atropine is used before neostigmine in urine retention to protect the heart it will also block M3 receptors which are needed to contract the urinary bladder; so the useful effect of neostigmine will also be lost. Q13:When we can use atropine & what is the difference between it and atropine substitutes, atropine like drugs? A:Atropine substitutes are drugs which act like atropine and are used instead of it in certain indications because they have one or more advantage over it. For example, ipratropium has the advantage of local action in the bronchial tree so it is preferred to atropine in bronchial asthma. Atropine-like drugs are drugs
