Neuromuscular Blockers and Curare PDF

Neuromuscular Blockers and Curare Question Answer What is curare used for historically? Curare was used in South America as arrow poison to immobilize...

Neuromuscular Blockers and Curare Question Answer What is curare used for historically? Curare was used in South America as arrow poison to immobilize animals and in early medicinal uses for patients with tetanus and other spastic conditions. What is the significance of studying curare's chemical structure? The study of curare's chemical structure allowed for the synthesis of similar compounds with different properties. How are neuromuscular blockers classified? Neuromuscular blockers are broadly classified into Competitive neuromuscular blockers and Depolarizer neuromuscular blockers. What do competitive blockers do at the neuromuscular junction? Competitive blockers occupy nicotinic acetylcholine receptors (nAChRs) and prevent their activation by acetylcholine (ACh). What is required to trigger enough depolarization to fire a muscle Typically, additive miniature endplate potentials (EPPs) are action potential (AP) leading to contraction? required to trigger enough depolarization to fire a muscle action potential. What is the significance of the EPP value in neuromuscular The value of the EPP is required to be decreased to below 70% blockade? of its initial value to prevent the muscle action potential. What is the lifetime of ACh in the synapse compared to channel The lifetime of ACh in the synapse is shorter than the channel opening duration? opening duration due to the activity of acetylcholinesterase (AChE). How many molecules of ACh are required to activate the Two molecules of ACh are required to activate the receptors, receptors? while binding to only one antagonist molecule is enough to prevent its activity. What is the initial effect of depolarizing neuromuscular blockers The initial effect of depolarizing NMBs is depolarization leading to (NMBs)? fasciculation, followed by blockade and paralysis. How do AChE inhibitors affect neuromuscular blockers? AChE inhibitors can enhance the effects of neuromuscular blockers by preventing the breakdown of ACh. What is the sequence of muscle paralysis caused by Small, rapidly moving muscles (eyes, jaw, larynx) relax first, neuromuscular blockers? followed by muscles of the limbs and trunk, and finally intercostal muscles and diaphragm, leading to apnea. What is the duration of action of succinylcholine? The duration of action of succinylcholine is short, approximately 5 minutes. What are the effects of competitive neuromuscular blockers on No effect on CNS is observed for competitive neuromuscular the CNS? blockers, which are typically quaternary ammonium compounds. What is the effect of older agents like D-tubocurarine and Partial blockade of ganglia and adrenal medulla occurs with older pancuronium on the autonomic nervous system? agents, leading to hypotension and tachycardia. What is the clinical use of neuromuscular blockers during Muscle relaxation during surgery is facilitated to enable surgical surgery? manipulation, correction of dislocations, and intubation. How can the depth of neuromuscular blockade be assessed? The depth of neuromuscular blockade can be assessed by ulnar nerve stimulation and contraction of the thumb muscle (train of four). What are some clinical uses of neuromuscular blockers in Neuromuscular blockers are used to facilitate intubation, control critically ill patients? intracranial pressure (ICP) in traumatic brain injury, and reduce oxygen consumption. What are some drug interactions with neuromuscular blockers? Some inhalation anesthetics can stabilize endplate potentials and reduce competitive NMB doses; aminoglycosides can potentiate NMBs by preventing ACh release; and calcium channel blockers can also potentiate NMB effects. What are some adverse effects of neuromuscular blockers? Adverse effects include apnea, cardiovascular collapse, respiratory depression, and increased hypokalemia with succinylcholine. Question Answer What is malignant hyperthermia and how is it treated? Malignant hyperthermia is a reaction to depolarizing NMBs and inhalation anesthetics characterized by contracture, rigidity, heat production, metabolic acidosis, and tachycardia. It is treated by cooling, managing acidosis, and using dantrolene. What are the pharmacological actions of nicotine? Nicotine initially stimulates ganglionic receptors leading to early EPSP; high concentrations lead to persistent depolarization and eventual blockade. What are the effects of nicotine on the CNS and peripheral In small doses, nicotine produces mild CNS stimulation, mild nervous system? analgesia, and respiratory excitation. Increased doses can cause tremors, convulsions, and respiratory failure. What are ganglionic blockers and how are they classified? Ganglionic blockers are classified into two categories: depolarizing and competitive. What are the adverse effects associated with ganglionic blockers? Adverse effects include dry mouth, postural hypotension, constipation, blurred vision, and urine retention.