Which equals the anti-inflammatory activity of 50 mg of prednisone (Deltasone)?

Which equals the anti-inflammatory activity of 50 mg of prednisone (Deltasone)?

• A. 100 mg cortisol (Solu-Cortef)
• B. 80 mg methylprednisolone (Solu-Medrol)
• C. 7.5 mg dexamethasone (Decadron)
• D. 4 mg betamethasone (Celestone)

Answer: (C)

The key idea is converting glucocorticoids by anti-inflammatory potency. Dexamethasone is about 6–7 times more potent than prednisone for anti-inflammatory effects, so small amounts of dexamethasone can match larger prednisone doses. The standard equivalence is roughly 5 mg prednisone equals 0.75 mg dexamethasone. Scaling up, 50 mg prednisone is 10 times 5 mg, so it matches about 10 × 0.75 mg = 7.5 mg dexamethasone. That makes the dexamethasone option the correct match for the anti-inflammatory activity of 50 mg prednisone. Why the others don’t fit: hydrocortisone (cortisol) is much weaker—roughly 5 mg prednisone would correspond to about 20 mg hydrocortisone, so 50 mg prednisone would need around 200 mg hydrocortisone, not 100 mg. Methylprednisolone is about 4 mg per 5 mg prednisone, so 50 mg prednisone would align with about 40 mg methylprednisolone; 80 mg is too high. Betamethasone is roughly 0.6 mg per 5 mg prednisone, so 50 mg prednisone would be about 6 mg betamethasone; 4 mg is lower than the needed amount.

The key idea is converting glucocorticoids by anti-inflammatory potency. Dexamethasone is about 6–7 times more potent than prednisone for anti-inflammatory effects, so small amounts of dexamethasone can match larger prednisone doses. The standard equivalence is roughly 5 mg prednisone equals 0.75 mg dexamethasone. Scaling up, 50 mg prednisone is 10 times 5 mg, so it matches about 10 × 0.75 mg = 7.5 mg dexamethasone. That makes the dexamethasone option the correct match for the anti-inflammatory activity of 50 mg prednisone.

Why the others don’t fit: hydrocortisone (cortisol) is much weaker—roughly 5 mg prednisone would correspond to about 20 mg hydrocortisone, so 50 mg prednisone would need around 200 mg hydrocortisone, not 100 mg. Methylprednisolone is about 4 mg per 5 mg prednisone, so 50 mg prednisone would align with about 40 mg methylprednisolone; 80 mg is too high. Betamethasone is roughly 0.6 mg per 5 mg prednisone, so 50 mg prednisone would be about 6 mg betamethasone; 4 mg is lower than the needed amount.