Also, Codeine can obtund you and it also supresses the cough reflex.    From Wordnik.com.  [Alex Jones' Prison Planet.com] Reference

The manner in which external force acts upon the body is very little subject to the regulation of the will; no man can at pleasure obtund or invigorate his senses, prolong the agency of any impulse, or continue the presence of any image traced upon the eye, or any sound infused into the ear.    From Wordnik.com.  [The Rambler, sections 55-112 (1750-1751); from The Works of Samuel Johnson in Sixteen Volumes, Vol. IV] Reference

While we live upon the level with the rest of mankind, we are reminded of our duty by the admonitions of friends and reproaches of enemies; but men who stand in the highest ranks of society, seldom hear of their faults; if by any accident an opprobrious clamour reaches their ears, flattery is always at hand to pour in her opiates, to quiet conviction, and obtund remorse.    From Wordnik.com.  [The Works of Samuel Johnson, Volume 03 The Rambler, Volume II] Reference

(and it is granted they are to be preferred above all other earthly things); but where they fill and possess the heart, where they weaken and obtund the affections unto things spiritual, heavenly, and eternal, unless we are mortified unto them, the heart will never be in a good frame, nor is capable of that degree in the grace of repentance which we seek.    From Wordnik.com.  [Gospel Grounds and Evidences of the Faith of God���s Elect] Reference