Autonomic Nervous Systems
The following drug causes dry mouth/warm skin tachycardia, mydriasis: (AIIMS Nov 2009)
a. Anticholinergics inhibit cholinergic responses and produce a state that can be remembered by the mnemonics given below.
i. Blind as a bat (blurred vision) ii. Dry as a bone (dry mouth)
iii. Red as a beet (flushing) iv. Mad as a hatter (confusion)
v. Hot as a hare (hyperthermia) vi. Can’t see (vision changes)
vii. Can’t pee (urinary retention)
Anticholinergic drugs block the actions of acetylcholine at constrictor pupil muscle, block salivary secretin (most sensitive secretion) and cause dry mouth. Warm skin occurs due to blockade of sympathetic cholinergic fibers.
b. Sympathomimetics can cause restlessness, tachycardia, increase in blood pressure, hyperglycemia, hypokalemia and tremors in overdose. Overdose is treated by beta-blockers.
c. Cholinergic overdose causes:
i. D= diarrhea ii. U= urination
iii. M= meiosis iv. B= bradycardia/bronchospasm
v. L= lacrimation vi. E= excitation of skeletal muscle
vii. S= salivation
d. Treatment of cholinergic overdose is atropine.