The antidote to warfarin toxicity is what?
Vitamin B12.
Vitamin K.
Calcium gluconate.
Protamine sulfate
The Correct Answer is B
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
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Propranolol is a beta-blocker that can cause bronchoconstriction and worsen asthma symptoms.
Asthma is a reversible airway disease that is a contraindication for taking propranolol.
Choice A, tachycardia, is not a contraindication for taking propranolol.In fact, propranolol can be used to treat some types of tachycardia, such as atrial fibrillation or supraventricular tachycardia, by slowing down the heart rate.
Choice C, hypertension, is not a contraindication for taking propranolol.Propranolol can be used to treat hypertension by reducing the cardiac output and peripheral resistance.
Choice D, glaucoma, is not a contraindication for taking propranolol.Propranolol does not affect the intraocular pressure or the aqueous humor production.However, some other beta-blockers, such as timolol, can be used to treat glaucoma by lowering the intraocular pressure.
Correct Answer is A
Explanation
Hypokalemia is a condition of low potassium levels in the blood, which can be caused by diuretics such as furosemide (Lasix) that increase the excretion of potassium in the urine. Potassium is an important electrolyte that helps regulate the function of nerves and muscles, including the heart.Low potassium levels can cause symptoms such as confusion, tremors, muscle cramps, and nausea, which are consistent with the patient’s presentation.
Choice B, renal failure, is wrong because furosemide is used to treat fluid retention and edema caused by kidney disease, not to cause it.Renal failure would also cause symptoms such as decreased urine output, swelling, fatigue, and shortness of breath, which are not mentioned in the question.
Choice C, hyperkalemia, is wrong because hyperkalemia is a condition of high potassium levels in the blood, which can be caused by kidney disease or certain medications that decrease the excretion of potassium in the urine.Hyperkalemia can cause symptoms such as weakness, irregular heartbeat, paralysis, and chest pain, which are different from the patient’s symptoms.
Choice D, heart failure, is wrong because furosemide is also used to treat fluid retention and edema caused by heart failure, not to cause it.Heart failure would also cause symptoms such as shortness of breath, coughing, fatigue, and rapid weight gain, which are not mentioned in the question.
Normal ranges for potassium levels in the blood are 3.5 to 5.0 milliequivalents per liter (mEq/L) for adults and 3.4 to 4.7 mEq/L for children.
A level below 3.5 mEq/L is considered hypokalemic and a level above 5.0 mEq/L is considered hyperkalemic.
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