A nurse in a provider's office is monitoring blood electrolytes for four clients who take digoxin.
Which of the following electrolyte values increases a client's risk for digoxin toxicity?

Alpha 1 adrenergic blocking agents have a vasodilating effect and can be used for the management of hypertension. They work by blocking the alpha 1 receptors on the vascular smooth muscle, which normally cause vasoconstriction when stimulated by catecholamines like epinephrine and norepinephrine.By preventing this constriction, alpha 1 blockers lower the peripheral resistance and blood pressure

Choice A is wrong because alpha 3 adrenergic blockers do not exist.There are only two types of alpha receptors: alpha 1 and alpha 2

Choice B is wrong because alpha 2 adrenergic antagonists do not have a vasodilating effect.

They block the alpha 2 receptors, which are located presynaptically on the sympathetic nerve terminals and postsynaptically on some vascular smooth muscle cells.Alpha 2 receptors inhibit the release of norepinephrine when activated, so blocking them would increase the sympathetic activity and vasoconstriction

Choice C is wrong because alpha 1 adrenergic agonists do not have a vasodilating effect.

They stimulate the alpha 1 receptors, which cause vasoconstriction and increase the blood pressure.Alpha 1 agonists are used to treat hypotension and nasal congestion

Vitamin K is the antidote for warfarin toxicity because it can reverse the effects of warfarin by restoring the clotting factors.Warfarin is an oral anticoagulant that works by inhibiting vitamin K epoxide reductase, an enzyme that activates vitamin K in the body.Vitamin K is needed for the synthesis of active coagulation factors, such as II, VII, IX and X.By blocking vitamin K, warfarin reduces the blood’s clotting activity and prevents the formation of blood clots.

Choice A is wrong because vitamin B12 is not involved in the coagulation cascade.Vitamin B12 is mainly involved in DNA synthesis, red blood cell production and nerve function.

Choice C is wrong because calcium gluconate is not an antidote for warfarin toxicity.Calcium gluconate is used to treat low blood calcium levels or hypocalcemia.Calcium is also a cofactor for some coagulation factors, but it does not reverse the effects of warfarin.

Choice D is wrong because protamine sulfate is not an antidote for warfarin toxicity.

Protamine sulfate is used to reverse the effects of heparin, another type of anticoagulant that works by inhibiting thrombin and factor Xa.

Protamine sulfate does not affect the vitamin K-dependent coagulation factors that are inhibited by warfarin.

Normal ranges for coagulation tests that are affected by warfarin are:

• Prothrombin time (PT): 11 to 13.5 seconds

• International normalized ratio (INR): 0.8 to 1.2

• Activated partial thromboplastin time (aPTT): 25 to 35 seconds