A nurse is obtaining a medical history from a client who is to start warfarin therapy and currently uses herbal supplements at home. The nurse should inform the client that which of the following herbal supplements can interact adversely with warfarin?

Choice A reason: Vitamin K is the antidote for warfarin, not heparin. Vitamin K reverses the effects of warfarin by increasing the synthesis of clotting factors in the liver.

Choice B reason: Glucagon is the antidote for insulin, not heparin. Glucagon increases the blood glucose level by stimulating the breakdown of glycogen in the liver.

Choice C reason: Protamine is the antidote for heparin, not vitamin K or glucagon. Protamine neutralizes the effects of heparin by binding to it and forming a stable complex.

Choice D reason: Iron is not an antidote for any anticoagulant. Iron is a mineral that is essential for the production of hemoglobin and red blood cells.

Choice A reason: Blood pressure 160/94 mm Hg is not a reason to withhold atenolol, as it is a beta-blocker that lowers blood pressure and reduces the workload of the heart. Atenolol is indicated for hypertension, angina, and arrhythmias. The nurse should administer atenolol as prescribed, unless the blood pressure is too low (hypotension).

Choice B reason: Heart rate 46/min is a reason to withhold atenolol, as it is a sign of bradycardia (slow heart rate), which can be a side effect of atenolol. Atenolol can decrease the heart rate by blocking the beta-1 receptors in the heart. The nurse should withhold atenolol if the heart rate is below 60 beats per minute or above 100 beats per minute, and report the finding to the provider.

Choice C reason: Oxygen saturation 95% is not a reason to withhold atenolol, as it is a normal value that indicates adequate oxygenation of the blood. Atenolol does not affect the oxygen saturation or the respiratory function. The nurse should monitor the oxygen saturation regularly, and report any signs of hypoxia (low oxygen level).

Choice D reason: Respiratory rate 18/min is not a reason to withhold atenolol, as it is a normal value that indicates normal breathing. Atenolol does not affect the respiratory rate or the respiratory function. The nurse should monitor the respiratory rate regularly, and report any signs of dyspnea (difficulty breathing).