A nurse is caring for a client who takes warfarin for atrial fibrillation and wants to use ginkgo biloba as a CAM product to improve his memory. The nurse should inform the client that ginkgo biloba may interact with warfarin in which of the following ways?

Choice A reason: This statement is correct and does not indicate a need for further teaching. The client should avoid taking licorice as an herb because it may cause irregular heart rhythms. Licorice contains glycyrrhizin, which can lower the potassium level in the blood and increase the risk of digoxin toxicity¹². Licorice may also increase blood pressure and interfere with the effects of some blood pressure medications¹².

Choice B reason: This statement is also correct and does not indicate a need for further teaching. The client should monitor his pulse rate and report any changes to his health care provider. Digoxin can affect the heart rate and rhythm, and cause bradycardia (slow heart rate) or arrhythmias (irregular heartbeats)¹². The client should check his pulse before taking digoxin, and if it is below 60 beats per minute, he should skip the dose and call his health care provider¹². The client should also report any signs of digoxin toxicity, such as nausea, vomiting, loss of appetite, blurred vision, yellow or green halos around objects, confusion, or weakness¹².

Choice C reason: This statement is incorrect and indicates a need for further teaching. The client should not take digoxin with food or milk to prevent stomach upset. Food or milk may decrease the absorption of digoxin and reduce its effectiveness¹². Digoxin should be taken on an empty stomach, at least one hour before or two hours after a meal¹². If the client experiences stomach upset from digoxin, he should consult his health care provider for advice¹².

Choice D reason: This statement is also correct and does not indicate a need for further teaching. The client should check his weight daily and report any sudden increase to his health care provider. Digoxin is used to treat heart failure, a condition in which the heart cannot pump enough blood to meet the body's needs¹². One of the symptoms of heart failure is fluid retention, which can cause weight gain, swelling of the legs or ankles, shortness of breath, or difficulty breathing¹². A sudden increase in weight may indicate worsening of heart failure and require adjustment of the treatment plan¹².

Choice A reason: This statement is accurate and appropriate for counseling a client who has undergone a kidney transplant and is taking cyclosporine as an immunosuppressant to prevent organ rejection. The client should avoid taking St. John's wort as an herb because it may reduce the effectiveness of cyclosporine. St. John's wort is an herb that is used to treat depression, anxiety, and other mood disorders¹². However, St. John's wort can induce the enzyme cytochrome P450 3A4, which is involved in the metabolism of cyclosporine, and decrease its blood level¹²³. This may increase the risk of organ rejection or transplant failure in the client¹²³.

Choice B reason: This statement is incorrect and inappropriate for counseling a client who has undergone a kidney transplant and is taking cyclosporine as an immunosuppressant to prevent organ rejection. The client should not take St. John's wort as an herb because it may enhance the effectiveness of cyclosporine. As mentioned above, St. John's wort can reduce the effectiveness of cyclosporine by lowering its blood level¹²³. Taking St. John's wort with cyclosporine may result in subtherapeutic doses of cyclosporine and compromise the client's transplant outcome¹²³.

Choice C reason: This statement is incorrect and inappropriate for counseling a client who has undergone a kidney transplant and is taking cyclosporine as an immunosuppressant to prevent organ rejection. The client should not take cyclosporine with grapefruit juice to increase its absorption. Grapefruit juice can inhibit the enzyme cytochrome P450 3A4, which is involved in the metabolism of cyclosporine, and increase its blood level¹²³. This may increase the risk of side effects or toxicity of cyclosporine, such as kidney damage, high blood pressure, tremors, headache, or infection¹²³.

Choice D reason: This statement is incorrect and inappropriate for counseling a client who has undergone a kidney transplant and is taking cyclosporine as an immunosuppressant to prevent organ rejection. The client should not take cyclosporine with milk or yogurt to improve its digestion. Milk or yogurt may decrease the absorption of cyclosporine and reduce its effectiveness¹². Cyclosporine should be taken on an empty stomach, at least one hour before or two hours after a meal¹². If the client experiences stomach upset from cyclosporine, he should consult his health care provider for advice¹².