Which of the following correctly distinguishes the pharmacokinetics of atropine from glycopyrrolate?

• A Glycopyrrolate crosses the blood-brain barrier and causes CNS excitation; atropine does not
• B Atropine is a quaternary ammonium compound; glycopyrrolate is a tertiary amine
• C Glycopyrrolate is a quaternary ammonium compound and does not cross the blood-brain barrier ✓
• D Both have similar CNS penetration due to equivalent lipid solubility

Explanation

Glycopyrrolate is a quaternary ammonium salt that carries a permanent positive charge, preventing passage through the blood-brain barrier; it therefore lacks CNS side effects and is preferred when central antimuscarinic effects are undesirable (e.g., in neonates or to avoid post-operative confusion). Atropine is a tertiary amine with high lipid solubility that readily crosses into the CNS. Their quaternary/tertiary structure is a key pharmacokinetic differentiator.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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