A patient with atrial fibrillation has been prescribed digoxin (Lanoxin). The nurse should monitor which laboratory value to evaluate therapeutic effectiveness?

Nifedipine is a calcium channel blocker that lowers blood pressure by relaxing the blood vessels and reducing the workload of the heart.

The following instructions should be included in the teaching:

• Avoid drinking alcohol while taking this medication.Alcohol can increase the risk of side effects such as dizziness, flushing, headache, and low blood pressure.

• Monitor your blood pressure and pulse regularly.This will help to evaluate the effectiveness of the medication and detect any abnormal changes.Normal blood pressure for adults is less than 130/80 mm Hg and normal pulse rate is 60 to 100 beats per minute.

• Report any swelling in your ankles or feet to your provider.This can be a sign of fluid retention or heart failure, which are possible complications of nifedipine.

• Do not stop taking this medication abruptly.This can cause a rebound increase in blood pressure and chest pain.The dose should be tapered gradually under the supervision of the provider.

Choice E is wrong because chewing or crushing the sustained-release tablet can cause too much of the drug to be released at once, which can lead to overdose or severe side effects.

The tablet should be swallowed whole with a glass of water.

Warfarin is an anticoagulant that prevents blood clots from forming or growing larger. It works by inhibiting the synthesis of vitamin K-dependent clotting factors in the liver. The INR (international normalized ratio) is a measure of how long it takes the blood to clot.The therapeutic range for INR depends on the indication for warfarin therapy, but for atrial fibrillation, it is usually between 2 and 3. An INR level of 3.5 is above the therapeutic range, which means the blood is too thin and the patient is at risk of bleeding. The nurse should hold the warfarin dose and notify the physician, who may order vitamin K to reverse the effects of warfarin.

Choice A) Administer vitamin K as ordered by physician is wrong because vitamin K is not indicated unless the physician orders it based on the patient’s condition and INR level.

Vitamin K is an antidote for warfarin overdose and can reverse its anticoagulant effects.

However, administering vitamin K without a physician’s order may cause the INR to drop below the therapeutic range and increase the risk of clotting.

Choice B) Administer heparin as ordered by physician is wrong because heparin is another anticoagulant that works by activating antithrombin, a natural inhibitor of clotting factors.

Heparin is used for acute treatment of thromboembolic disorders, such as deep vein thrombosis or pulmonary embolism.

It is not indicated for atrial fibrillation unless there is evidence of acute thrombosis.

Administering heparin to a patient with an elevated INR would increase the risk of bleeding.

Choice C) Administer warfarin as ordered by physician is wrong because warfarin is the cause of the elevated INR and should be withheld until the INR returns to the therapeutic range.

Continuing to administer warfarin would further increase the INR and the risk of bleeding.