Correct Answer: A

Rationale: The correct answer is A: Increased risk of pregnancy. Certain antibiotics and anticonvulsants can decrease the effectiveness of oral contraceptives by inducing liver enzymes that metabolize the hormones more quickly. This interaction can lead to a decreased contraceptive effect, thereby increasing the risk of pregnancy. Choices B, C, and D are incorrect as they do not directly relate to the effect of antibiotics and antiseizure medications on oral contraceptives.

Correct Answer: C

Rationale: In a client with a pneumothorax receiving oxygen therapy, improved breath sounds on the affected side would indicate effective treatment. This finding suggests that the collapsed lung is re-expanding, allowing air to flow more freely in and out of the affected area. Choices A, B, and D are incorrect: Increased respiratory rate, decreased oxygen saturation levels, and increased dyspnea and chest pain are signs of ineffective treatment or worsening of the condition in a client with a pneumothorax.

Correct Answer: A

Rationale: The correct answer is A: Increased risk of venous thromboembolism. Tamoxifen is known to increase the risk of venous thromboembolism, a serious side effect. Patients should be educated about the signs and symptoms of blood clots such as swelling, redness, warmth, or pain in the affected limb. Choices B, C, and D are incorrect because tamoxifen is not associated with an increased risk of hot flashes, cataracts, or bone fractures.

Correct Answer: A

Rationale: The correct answer is A. Raloxifene works by decreasing bone resorption and increasing bone density. This helps in preventing further bone loss and reducing the risk of fractures in patients with osteoporosis. Choice B is incorrect because raloxifene does not stimulate the formation of new bone, but rather helps to maintain existing bone mass. Choice C is incorrect as raloxifene does not directly increase calcium absorption in the intestines. Choice D is also incorrect as raloxifene does not increase the excretion of calcium through the kidneys.

Correct Answer: B

Rationale: Emotional stress can trigger a relapse in multiple sclerosis by exacerbating symptoms. While taking an over-the-counter multivitamin and getting a flu shot are generally safe, they are not typically known to trigger MS relapses. Engaging in strenuous physical activity, if done carefully, can actually have benefits for individuals with MS by improving strength and mobility, so it is less likely to be the cause of a relapse.