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 incorrect and inappropriate for identifying the interaction between echinacea and lisinopril. Echinacea does not interact with lisinopril, an ACE inhibitor for blood pressure. There is no evidence that echinacea affects the blood pressure or the pharmacokinetics of lisinopril¹².

Choice B reason: This statement is incorrect and inappropriate for identifying the interaction between echinacea and amoxicillin. Echinacea does not interact with amoxicillin, a penicillin antibiotic for infection. There is no evidence that echinacea affects the antibacterial activity or the pharmacokinetics of amoxicillin¹².

Choice C reason: This statement is correct and appropriate for identifying the interaction between echinacea and prednisone. Echinacea may interact with prednisone, a corticosteroid for inflammation, by reducing its effectiveness or increasing its side effects. Echinacea has immunostimulatory properties that may counteract the immunosuppressive effects of prednisone¹². Echinacea may also induce the enzyme cytochrome P450 3A4, which is involved in the metabolism of prednisone, and decrease its blood level¹². Furthermore, echinacea may increase the risk of infection or bleeding in people who take prednisone¹².

Choice D reason: This statement is incorrect and inappropriate for identifying the interaction between echinacea and metformin. Echinacea does not interact with metformin, a biguanide for diabetes mellitus. There is no evidence that echinacea affects the blood glucose or the pharmacokinetics of metformin¹².

Choice E reason: This statement is correct and appropriate for identifying the interaction between echinacea and fluoxetine. Echinacea may interact with fluoxetine, an SSRI for depression, by increasing its side effects or toxicity. Echinacea may inhibit the enzyme cytochrome P450 2D6, which is involved in the metabolism of fluoxetine, and increase its blood level¹². Echinacea may also increase the risk of serotonin syndrome, a potentially life-threatening condition caused by excessive serotonin in the brain, in people who take fluoxetine¹²..

The correct answer is

D. All of the above.

Choice A reason: This statement is correct and reflects one of the possible adverse effects or interactions that may occur with biologically based therapies such as herbs and supplements. Allergic reactions or hypersensitivity can occur when the body's immune system reacts to a foreign substance, such as a plant extract or a dietary supplement, and produces antibodies and other chemicals that cause symptoms such as itching, rash, hives, swelling, or anaphylaxis (a severe and potentially life-threatening reaction). Some examples of herbs or supplements that may cause allergic reactions include echinacea, chamomile, garlic, ginkgo, and bee pollen.

Choice B reason: This statement is also correct and reflects another possible adverse effect or interaction that may occur with biologically based therapies such as herbs and supplements. Hepatic or renal toxicity or dysfunction can occur when the liver or the kidneys are damaged or impaired by a substance, such as a plant extract or a dietary supplement, that may be toxic or interfere with their normal function. Some examples of herbs or supplements that may cause hepatic or renal toxicity or dysfunction include kava, comfrey, chaparral, licorice, ephedra, and aristolochia.

Choice C reason: This statement is also correct and reflects another possible adverse effect or interaction that may occur with biologically based therapies such as herbs and supplements. Gastrointestinal distress or bleeding can occur when the stomach or the intestines are irritated or injured by a substance, such as a plant extract or a dietary supplement, that may cause inflammation, ulceration, perforation, or bleeding. Some examples of herbs or supplements that may cause gastrointestinal distress or bleeding include aloe vera, cascara sagrada, senna, ginger, ginseng, garlic, ginkgo, and feverfew.

Choice D reason: This statement is correct because it includes all of the above statements. Biologically based therapies such as herbs and supplements may cause various adverse effects or interactions depending on the type, dose, duration, quality, purity, and combination of these products. Therefore, choice D is the best answer for assessing the client for possible adverse effects or interactions that may occur with biologically based therapies.