A nurse is teaching a client who has a new prescription for aluminum hydroxide to treat heartburn. The nurse should instruct the client to monitor for and report which of the following adverse reactions?

Choice A reason: This is incorrect. SQ (subcutaneous) administration involves injecting a drug into the fatty tissue under the skin. This route is slower than IV or IM administration, as the drug has to diffuse through the tissue before reaching the bloodstream.

Choice B reason: This is incorrect. PO (by mouth) administration involves swallowing a drug and absorbing it through the digestive system. This route is the slowest of all, as the drug has to pass through the stomach and the liver before reaching the bloodstream. The drug may also be affected by the first pass effect, which reduces its bioavailability.

Choice C reason: This is correct. IV (intravenous) administration involves injecting a drug directly into a vein. This route is the fastest of all, as the drug enters the bloodstream immediately and reaches the target site quickly. The drug also has 100% bioavailability, meaning none of it is lost or degraded.

Choice D reason: This is incorrect. IM (intramuscular) administration involves injecting a drug into a muscle. This route is faster than SQ or PO administration, as the drug can be absorbed by the capillaries in the muscle. However, it is still slower than IV administration, as the drug has to cross the muscle membrane before reaching the bloodstream.

Choice A reason: This is correct. Nausea, vomiting, and diarrhea are the most common side effects of metformin, especially when the drug is started or the dose is increased. These side effects occur because metformin can interfere with the absorption of glucose and other nutrients in the intestines, causing osmotic diarrhea. The nurse should advise the client to take metformin with food, start with a low dose and gradually increase it, and drink plenty of fluids to prevent dehydration. The nurse should also monitor the client for signs of lactic acidosis, a rare but serious complication of metformin that causes severe diarrhea, abdominal pain, muscle cramps, and difficulty breathing.

Choice B reason: This is incorrect. Palpitations are not a common side effect of metformin. Palpitations are the sensation of a rapid, irregular, or pounding heartbeat, which can be caused by various factors, such as stress, anxiety, caffeine, nicotine, or heart problems. Metformin does not affect the heart rate or rhythm directly, but it can lower the blood sugar levels, which can trigger the release of adrenaline, a hormone that can cause palpitations. The nurse should check the client's blood sugar levels and advise the client to eat regular meals and snacks, avoid alcohol and caffeine, and report any chest pain or shortness of breath.

Choice C reason: This is incorrect. Headaches are not a common side effect of metformin. Headaches are the pain or discomfort in the head, scalp, or neck, which can be caused by various factors, such as stress, dehydration, or sinus infection. Metformin does not cause headaches directly, but it can lower the blood sugar levels, which can cause headaches as a symptom of hypoglycemia. The nurse should check the client's blood sugar levels and advise the client to eat regular meals and snacks, drink plenty of water, and take painkillers as needed.

Choice D reason: This is incorrect. Heartburn is not a common side effect of metformin. Heartburn is the burning sensation in the chest or throat, which is caused by the reflux of stomach acid into the esophagus. Metformin does not cause heartburn directly, but it can worsen it if the client already has gastroesophageal reflux disease (GERD), a condition where the lower esophageal sphincter is weak or relaxed and allows the acid to flow back. The nurse should advise the client to take metformin with food, avoid spicy or fatty foods, elevate the head of the bed, and take antacids as needed.