Which antidiabetic medication is associated with decreased visual acuity due to macular edema?

• A. Metformin (Glucophage)
• B. Pioglitazone (Actos), Rosiglitazone (Avandia)
• C. Topiramate (Topamax)
• D. Ritalin, Dexedrine (ADHD)

Answer: (B)

Macular edema is a possible adverse effect of thiazolidinediones used for type 2 diabetes, such as pioglitazone and rosiglitazone. These drugs can cause fluid accumulation in the macula, leading to decreased visual acuity. The practical takeaway is that new or worsening blurred vision in a patient taking a TZD should prompt an ophthalmic evaluation for macular edema, and consideration of adjusting or stopping the medication if edema is found. Vision often improves after the drug is discontinued or altered.

Metformin is not typically associated with macular edema. Topiramate can cause blurred vision but through different mechanisms (often acute myopia and angle-closure glaucoma, not macular edema). ADHD stimulants like methylphenidate or amphetamines are not linked to macular edema as a diabetic drug effect.