Question

All of the following are true statements regarding the use of sodium fluoride in the treatment of otosclerosis EXCEPT:

• A. It inhibits osteoblastic activity
• B. It is used in the active phase of otosclerosis when the Schwartze sign is positive
• C. It has an antienzymatic action on proteolytic enzymes toxic to the cochlea
• D. It is contraindicated in renal failure patients

Hint:

Fluoride hardens spongy bone by favouring osteoblasts; the osteoblast inhibition claim is the false one.

Answer 1

The Correct Option is A

Step 1: Understand the drug action. Sodium fluoride is given in active otosclerosis to promote maturation and recalcification of the spongy otosclerotic bone. It encourages the formation of denser, mature bone.
Step 2: Evaluate option A. The statement that it inhibits osteoblastic activity is false. Sodium fluoride actually favours osteoblastic, bone forming activity and inhibits the osteoclastic, bone resorbing process, helping convert active spongy bone to inactive sclerotic bone. Since the question asks for the exception, this false statement is the answer.
Step 3: Confirm option B. It is indeed indicated in the active phase, signalled by a positive Schwartze sign (reddish hue over the promontory due to vascular active otospongiosis), so this is a true statement.
Step 4: Confirm option C. Sodium fluoride has an antienzymatic effect on the proteolytic (hydrolytic) enzymes released by active foci that are toxic to the cochlea, which is true.
Step 5: Confirm option D. It is relatively contraindicated in renal failure because fluoride is excreted renally and can accumulate, which is true.
Step 6: Conclusion. The false statement, and therefore the answer to this except question, is that it inhibits osteoblastic activity, option 1.