Which drugs are anticholinergic? (Select all that apply)

Choice A reason: Fibric acid derivatives, like fenofibrate, lower triglycerides by activating PPAR-alpha, reducing VLDL production. They are not commonly associated with myopathy, though gastrointestinal upset or liver enzyme elevation may occur. Myopathy is more characteristic of statins, making this an incorrect class for monitoring.

Choice B reason: Niacin lowers lipids by inhibiting VLDL synthesis but is not significantly linked to myopathy. Its primary side effects include flushing and hepatotoxicity due to prostaglandin release and metabolic stress. Muscle pain is a hallmark of statins, not niacin, making this incorrect.

Choice C reason: Bile acid sequestrants, like cholestyramine, bind bile acids, reducing cholesterol absorption. They cause gastrointestinal side effects like constipation but not myopathy. Their mechanism does not affect muscle tissue, unlike statins, which inhibit HMG-CoA reductase, making this class irrelevant for myopathy monitoring.

Choice D reason: Statins, like simvastatin, inhibit HMG-CoA reductase, reducing cholesterol synthesis. They can cause myopathy by disrupting muscle cell membranes or mitochondrial function, leading to muscle pain or rare rhabdomyolysis. Monitoring for myopathy is critical, as it can progress to severe muscle damage, making this the correct class.

Choice A reason: Reducing raw vegetables and fruit is not necessary with simvastatin. Dietary vitamin K may affect warfarin, but statins are unaffected by fruits or vegetables, except grapefruit, which inhibits CYP3A4, increasing simvastatin levels. A balanced diet supports cardiovascular health, making this instruction incorrect.

Choice B reason: Drug interactions are not rare with simvastatin, a statin metabolized by CYP3A4. Inhibitors like grapefruit juice or antifungals increase simvastatin levels, risking toxicity, while inducers reduce efficacy. Patients must be educated about potential interactions, making this statement incorrect and misleading for safe statin use.

Choice C reason: Reporting muscle pain immediately is critical with simvastatin, as it may indicate myopathy or rare rhabdomyolysis. Statins disrupt muscle cell membranes, causing pain or weakness. Early reporting allows monitoring of creatine kinase levels and prevents progression to severe muscle damage, ensuring patient safety.

Choice D reason: Reporting bleeding or yellow skin (jaundice) is essential, as simvastatin can cause hepatotoxicity, elevating liver enzymes, or rare bleeding due to drug interactions. Jaundice indicates liver dysfunction, and bleeding may result from interactions with anticoagulants, necessitating prompt reporting to adjust therapy or monitor liver function.

Choice E reason: Limiting fluid intake is not required with simvastatin. Fluid overload is unrelated to statins, which affect cholesterol synthesis, not fluid balance. Adequate hydration supports general health, and no evidence suggests fluid restriction is necessary, making this instruction irrelevant and potentially harmful.