A client who is taking an oral contraceptive receives a new prescription for erythromycin. Which instruction should the nurse provide to the client?

Choice A reason: Stopping the oral contraceptive immediately is not necessary and may increase the risk of unintended pregnancy. Erythromycin can reduce the effectiveness of oral contraceptives by interfering with their metabolism, but it does not make them completely ineffective.

Choice B reason: Taking the medications at least 12 hours apart is not sufficient to prevent the interaction between erythromycin and oral contraceptives. The interaction can occur regardless of the timing of the doses.

Choice C reason: Using an additional form of contraception is the best instruction for the client who is taking an oral contraceptive and erythromycin. This can prevent pregnancy in case the oral contraceptive fails due to the interaction with erythromycin. The additional form of contraception should be non-hormonal, such as a barrier method or a copper intrauterine device.

Choice D reason: Avoiding prolonged exposure to direct sunlight is a good advice for anyone taking erythromycin, as it can cause photosensitivity and increase the risk of sunburn. However, this is not related to the interaction with oral contraceptives and does not affect their efficacy.

Choice A reason: Risedronate is a bisphosphonate that is used to treat osteoporosis by inhibiting bone resorption. It should be taken on an empty stomach with a full glass of water at least 30 minutes before any other food, beverage, or medication. This is because food, milk, and antacids can interfere with the absorption of risedronate and reduce its effectiveness.

Choice B reason: Milk contains calcium, which can bind to risedronate and prevent its absorption. Therefore, the client should not drink milk with or within 2 hours of taking risedronate.

Choice C reason: Withholding the medication until the client's breakfast tray is available is not appropriate, as it would delay the administration of risedronate and disrupt the dosing schedule. The client should take risedronate as soon as possible after waking up and before eating anything.

Choice D reason: Consulting with a pharmacist about scheduling the dose one hour after the client eats is not necessary, as risedronate should be taken at least 30 minutes before any food or beverage. Taking risedronate one hour after eating may not ensure adequate absorption of the drug.