A nurse is assessing a client prior to administering atenolol. Which of the following findings should prompt the nurse to withhold the medication?

Choice A reason: This is incorrect because extravasation is not related to the lifetime cumulative dose limit of doxorubicin, but to the leakage of the medication from the vein into the surrounding tissue. Extravasation can cause severe tissue damage and necrosis, and should be prevented by using a central venous catheter and monitoring the infusion site.

Choice B reason: This is incorrect because red tinged urine and sweat are not related to the lifetime cumulative dose limit of doxorubicin, but to the normal excretion of the medication from the body. Red tinged urine and sweat are expected side effects of doxorubicin and do not indicate toxicity or harm.

Choice C reason: This is correct because an excess amount of doxorubicin can lead to cardiomyopathy, which is a serious and potentially fatal complication of the medication. Cardiomyopathy is a condition in which the heart muscle becomes weak and unable to pump blood effectively. The risk of cardiomyopathy increases with the cumulative lifetime dose of doxorubicin, which should not exceed 450 to 550 mg/m2.

Choice D reason: This is incorrect because myelosuppression is not related to the lifetime cumulative dose limit of doxorubicin, but to the dose-dependent effect of the medication on the bone marrow. Myelosuppression is a condition in which the production of blood cells is reduced, leading to anemia, leukopenia, and thrombocytopenia. Myelosuppression can be managed by adjusting the dose and frequency of doxorubicin and monitoring the blood counts.

Choice A reason: A headache is not likely due to the anxiety about the chest pain, as anxiety usually causes other symptoms, such as palpitations, sweating, or trembling. A headache is more likely related to the vasodilating action of nitroglycerin, which causes increased blood flow to the brain.

Choice B reason: A headache does not indicate tolerance to the medication, as tolerance usually manifests as a reduced effect of the medication on relieving chest pain. A headache is more likely a sign of the medication's potency, as it indicates that the nitroglycerin is reaching the systemic circulation.

Choice C reason: A headache is an expected adverse effect of the medication, as nitroglycerin causes vasodilation of the cerebral vessels, which can result in increased intracranial pressure and pain. A headache is usually mild and transient, and can be relieved by taking analgesics, such as acetaminophen.

Choice D reason: A headache is not an indication of an allergy to the medication, as an allergic reaction usually causes other symptoms, such as rash, itching, swelling, or difficulty breathing. A headache is more likely a pharmacological effect of the medication, rather than an immunological response.