Which medication should be readily available for the treatment of magnesium toxicity in a client receiving magnesium sulfate?

Calcium gluconate is the appropriate medication to have readily available for the treatment of magnesium toxicity, especially for patients receiving magnesium sulfate. Magnesium sulfate can lead to elevated levels of magnesium in the body, which may result in significant cardiovascular and neuromuscular effects, including respiratory depression and cardiac arrest. Calcium acts as an antagonist to magnesium; therefore, administering calcium gluconate can help stabilize the membranes of nerve and muscle cells, counteracting the effects of excessive magnesium.

In cases of magnesium toxicity, it is critical to act quickly to address the potentially life-threatening complications. Calcium gluconate works by providing an immediate source of calcium, helping to restore normal neuromuscular and cardiac function.

The other options do not serve this purpose. Zidovudine is an antiretroviral medication used primarily for HIV treatment, metformin is an oral hypoglycemic agent used for managing type 2 diabetes, and albuterol is a bronchodilator used in treating asthma and bronchospasm. None of these medications would be effective or appropriate in treating magnesium toxicity.