A nurse is taking a health history of a client who reports occasionally taking several over-the-counter medications, including an H2 receptor antagonist (famotidine). Which of the following outcomes indicates that famotidine is therapeutic?

Choice A reason: This is correct. The liver is the main organ responsible for drug metabolism. The enzymes that the body uses to metabolize drugs are present throughout the body but are most abundant in the liver. The liver can transform drugs into more polar and water-soluble compounds, which can then be excreted by the kidneys or the biliary system.

Choice B reason: This is incorrect. The lungs are not primarily responsible for drug metabolism, although they can play a minor role in some cases. The lungs can metabolize some drugs that are inhaled, such as anesthetics, or drugs that circulate through the pulmonary blood vessels, such as propranolol. However, the lungs have a lower capacity and a lower variety of enzymes than the liver.

Choice C reason: This is incorrect. The heart is not responsible for drug metabolism, although it can be affected by it. The heart is the organ that pumps blood throughout the body, delivering oxygen and nutrients to the tissues and organs. The heart can be influenced by the pharmacokinetics and pharmacodynamics of drugs, which are the processes of drug absorption, distribution, metabolism, and excretion, and the effects of drugs on the body, respectively.

Choice D reason: This is incorrect. The kidney is not primarily responsible for drug metabolism, although it is important for drug excretion. The kidney is the organ that filters the blood and removes waste products and excess fluid as urine. The kidney can excrete drugs that are water-soluble or that are not reabsorbed by the tubules. The kidney can also metabolize some drugs, such as aspirin, but to a lesser extent than the liver.

Choice A reason: Dextromethorphan (Robitussin) is not the correct medication for a patient with a productive cough. Dextromethorphan is a cough suppressant that works by acting on the brain to reduce the cough reflex. Dextromethorphan is used for a dry, nonproductive cough that is caused by irritation or inflammation. Dextromethorphan is not effective for a productive cough that produces mucus, and it may even be harmful by preventing the clearance of secretions from the lungs.

Choice B reason: Fluticasone (Flonase) is not the correct medication for a patient with a productive cough. Fluticasone is a corticosteroid that works by reducing inflammation and swelling in the nasal passages. Fluticasone is used for allergic rhinitis, which is a condition that causes sneezing, itching, and runny nose due to an allergic reaction. Fluticasone is not effective for a productive cough that produces mucus, and it may even worsen it by suppressing the immune system and increasing the risk of infection.

Choice C reason: Pseudoephedrine (Sudafed) is not the correct medication for a patient with a productive cough. Pseudoephedrine is a decongestant that works by constricting the blood vessels in the nasal passages and sinuses. Pseudoephedrine is used for nasal congestion, which is a condition that causes stuffy nose and difficulty breathing due to swelling of the mucous membranes. Pseudoephedrine is not effective for a productive cough that produces mucus, and it may even cause side effects such as increased blood pressure, insomnia, and anxiety.

Choice D reason: Guaifenesin (Mucinex) is the correct medication for a patient with a productive cough. Guaifenesin is an expectorant that works by thinning and loosening the mucus in the chest and throat. Guaifenesin is used for a productive cough that produces mucus, as it helps the cough to be more effective and clear the airways. Guaifenesin is generally safe and well tolerated, but it may cause some minor side effects such as nausea, vomiting, and headache.