Question

Drug induced myopathy can be caused by all of the following except:

• A. Atorvastatin.
• B. D-penicillamine.
• C. Ciprofloxacin.
• D. Chloroquine.

Hint:

Ciprofloxacin's musculoskeletal risk is tendon damage, not muscle fiber myopathy.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
We need the one drug that does NOT typically cause myopathy (muscle disease with weakness or pain), among four commonly tested drugs.

Step 2: Key Concept:
Several drug classes are well known causes of myopathy: statins (through direct muscle cell toxicity), certain antirheumatic drugs like D-penicillamine (through an autoimmune myositis like reaction), and antimalarials like chloroquine (through a vacuolar myopathy from lysosomal drug accumulation in muscle). Fluoroquinolones like ciprofloxacin are much better known for tendon problems, not for direct muscle fiber damage.

Step 3: Detailed Explanation:
Atorvastatin, a statin, is one of the most common drug causes of myopathy, ranging from mild muscle aches to severe rhabdomyolysis, so it is a genuine cause.
D-penicillamine, used in rheumatoid arthritis and Wilson's disease, can trigger an autoimmune type myositis resembling polymyositis, so it is a genuine cause.
Chloroquine, used for malaria and autoimmune disease, builds up in lysosomes of muscle cells over long term use and produces a distinct vacuolar myopathy, so it is a genuine cause.
Ciprofloxacin's main musculoskeletal side effect is tendinopathy and tendon rupture, especially of the Achilles tendon, this is a tendon problem, not a primary muscle fiber (myopathy) problem, so ciprofloxacin is not a classic cause of drug induced myopathy.

Step 4: Why the other options are wrong:
Atorvastatin, D-penicillamine, and chloroquine are all well documented causes of drug induced myopathy through different mechanisms, so they are correctly linked and are not the exception.

Step 5: Final Answer:
Ciprofloxacin is known for tendon damage, not myopathy.
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