A client diagnosed with type 2 diabetes will begin taking metformin (Glucophage). The nurse understands that the client is at risk for which serious condition(s) when taking metformin (Glucophage)?

Choice A rationale:

Respiratory distress is not a direct side effect of metformin. While metformin can cause a rare condition called lactic acidosis, which can lead to rapid breathing, respiratory distress is not a primary concern with metformin use.

Respiratory distress typically involves difficulty breathing due to other causes such as asthma, pneumonia, heart failure, or chronic obstructive pulmonary disease (COPD).

Choice B rationale:

Seizures are not a known side effect of metformin.

Seizures are typically associated with neurological conditions, such as epilepsy, or metabolic disturbances such as hypoglycemia or electrolyte imbalances.

Metformin does not directly affect the central nervous system in a way that would increase the risk of seizures.

Choice C rationale:

Lactic acidosis:

This is a rare but serious condition that can occur with metformin use.

It happens when lactic acid builds up in the bloodstream, causing the blood to become too acidic. Symptoms of lactic acidosis include:

Rapid breathing Nausea and vomiting Abdominal pain Muscle weakness Unusual sleepiness Feeling cold

Risk factors for lactic acidosis in patients taking metformin include:

Kidney disease Congestive heart failure Liver disease Dehydration

Excessive alcohol intake Recent surgery or heart attack

It's important to note that lactic acidosis is rare, occurring in about 3 to 10 cases per 100,000 people taking metformin per year.

Renal failure:

Metformin is primarily eliminated by the kidneys.

If kidney function is impaired, metformin can build up in the body, increasing the risk of lactic acidosis. Additionally, metformin can potentially cause kidney damage in rare cases, further worsening kidney function. It's crucial to monitor kidney function regularly in patients taking metformin.

Choice D rationale:

Hyperglycemia (high blood sugar) is not a side effect of metformin.

In fact, metformin is a medication used to lower blood sugar levels in people with type 2 diabetes. It works by:

Decreasing the amount of glucose produced by the liver Improving the body's sensitivity to insulin

Slowing the absorption of glucose from the intestines

Choice A rationale:

COPD (Chronic Obstructive Pulmonary Disease) is a chronic lung disease that causes airflow obstruction. While labetalol can cause some bronchoconstriction, it is generally considered safe for use in patients with COPD. However, it's essential to monitor respiratory status closely, especially in those with severe COPD.

Choice B rationale:

Narrow-angle glaucoma is an eye condition characterized by increased intraocular pressure (IOP) due to impaired drainage of aqueous humor. Labetalol can exacerbate this condition by further increasing IOP through its beta-blocking effects. This can lead to acute angle-closure glaucoma, a medical emergency that can result in permanent vision loss.

Specific mechanisms by which labetalol can increase IOP:

Reduced aqueous humor production: Beta-blockers like labetalol can decrease the production of aqueous humor, the fluid that maintains eye pressure. While this might seem beneficial, a significant reduction can lead to anterior chamber shallowing, which can mechanically block the drainage angle and trigger angle closure.

Impaired uveoscleral outflow: Beta-blockers can also impair the uveoscleral outflow pathway, an alternative route for aqueous humor drainage that becomes more important in glaucoma patients. This can further contribute to IOP elevation.

Vasoconstriction of ciliary blood vessels: Labetalol's alpha-blocking effects can cause vasoconstriction of the ciliary blood vessels, which supply blood to the ciliary body responsible for aqueous humor production. This can reduce blood flow and indirectly hinder aqueous humor drainage.

Pupillary dilation: Beta-blockers can cause pupillary dilation, which can mechanically narrow the anterior chamber angle and obstruct aqueous humor outflow.

Therefore, labetalol is generally contraindicated in patients with known narrow-angle glaucoma.

Choice C rationale:

Hypertension (high blood pressure) is one of the primary indications for labetalol. It is an effective antihypertensive medication that works by blocking beta receptors, leading to decreased heart rate, contractility, and blood pressure.

Choice D rationale:

Tachycardia (fast heart rate) can also be treated with labetalol due to its beta-blocking effects. It helps to slow down the heart rate and restore a normal rhythm.