Positively charged so cannot readily cross membranes.

Competes with ACh for binding to N_M receptors.  Does not activate receptors, so binding does not result in muscle contraction.  Causes muscle relaxation which can be overcome by increasing amount of ACh at the junction.

Tubocurarine's primary effect is muscle relaxation producing flaccid paralysis.  By causing the release of histamine and partial ganglionic blockade, this drug can lower blood pressure.  No CNS effects. Can be used for muscle relaxation during medical procedures (surgery, endotracheal intubation and electroconvulsive therapy).

Respiratory depression; hypotension, bradycardia, dysrhythmias, and cardiac arrest.  Patient's with myasthenia gravis or electrolyte imbalances may experience intensified effects of this drug.  Use with general anesthetics and some antibiotics can intensify effects of tubocurarine.  Use with ChE inhibitors can decrease effects.

Assess respiratory function during period of drug action.  Assess for hypotension.  Use caution with antibiotics.  Use with caution in patients with myasthenia gravis.

Binds to N_M receptors causing depolarization.  Remains bound, maintaining end plate in a state of constant depolarization.  By keeping the end-plate from repolarizing, the drug causes paralysis until plasma levels decline and the drug dissociates from the receptors.

Muscle relaxation leading to flaccid paralysis.  Paralysis produced by succinylcholine is preceded by transient contractions.  No CNS effects.  Used for muscle relaxation during short medical procedures, like endotracheal intubation, electroconvulsive therapy and endoscopy.

Prolonged apnea in patients with low pseudocholinesterase activity, malignant hyperthermia, post-op muscle pain, hyperkalemia.  Cholinesterase inhibitors and some antibiotics will potentiate the effects of succinylcholine.

Assess respiratory function during period of drug action.  Assess for hypotension.  Use caution with antibiotics.  Use with caution in patients with myasthenia gravis.  Assess for family history of malignant hyperthermia reaction.  Succinylcholine is contraindicated for patients with low cholinesterase activity.

Blocks ganglionic transmission in autonomic nervous system by competative antagonism with ACh at N_N receptors.  Also has two direct effects: vasodilation and histamine release, both of which can lower blood pressure.

Used therapeutically to produce controlled hypotension during surgery and to treat hypertensive crisis.

Dry mouth, blurred vision, photophobia, urinary retention, constipation, tachycardia, anhidrosis, hypotension and orthostatic hypotension.  

Monitor blood pressure and heart rate.  Position patient in supine or Trendelenburg's position to minimize hypotension, or raise the head and lower the feet if blood pressure is too high.