Differentiate tachyphylaxis from tolerance.

• A. Tachyphylaxis is a gradual decrease; tolerance is a rapid decrease after initial dosing.
• B. Tachyphylaxis is a rapid drop in response after initial dosing; tolerance is a gradual decrease requiring higher doses over time.
• C. Tachyphylaxis is receptor downregulation; tolerance is receptor upregulation.
• D. Tachyphylaxis and tolerance are the same phenomenon.

Answer: (B)