Pharmacology: Antidotes

Question 1

Acetaminophen toxicity

What is the MOA?

Answer 1

N-acetylcysteine (replenishes glutathione)

Question 2

Salicylate toxicity

Answer 2

NaHCO3 (alkalinize urine)

Dialysis

Question 3

Amphetamines (basic) toxicity

Answer 3

NH4Cl (acidify urine)

Question 4

Acetylcholinesterase inhibitor toxicity

Answer 4

Atropine (reverse mACh sx, but not nACh effects–muscle paralysis)
Pralidoxime (affects both m- and n-ACh sx)

Question 5

Organophosphate toxicity

Answer 5

Atropine (anti-ACh; reverse mACh sx, but not nACh effects–muscle paralysis)
Pralidoxime (affects both m- and n-ACh sx)

Question 6

Antimuscarinic, anticholinergic toxicity

Answer 6

Pysostigmine salicylate

Question 7

Beta-blocker overdose

Answer 7

Glucagon (increase of cAMP in the myocardium, in effect bypassing the β-adrenergic second messenger system)

Question 8

Digitalis toxicity - “yellow vision” with yellow/green halos, bradycardia, prolonged PR

Answer 8

Stop dig. Anti-dig Fab fragments (binds dig)

Treat arrythmias: normalize K+, give Lidocaine, Mg2+

Question 9

Iron

Answer 9

Deferoxamine (Fe chelator)

Question 10

Lead

Answer 10

CaEDTA
Dimercaprol (BAL)
Succimer (dimercaptosuccinic acid)
Penicillamine

Question 11

Mercury

Answer 11

CaEDTA
Dimercaprol (BAL)
Succimer (dimercaptosuccinic acid)

Question 12

Arsenic

Answer 12

Chelators:
Dimercaprol (BAL)
Succimer (dimercaptosuccinic acid)
Penicillamine

Question 13

Gold

Answer 13

Chelators:
Dimercaprol (BAL)
Succimer (dimercaptosuccinic acid)
Penicillamine

Question 14

Copper

Answer 14

Penicillamine

Question 15

Cyanide

Answer 15

Amyl nitrite: oxidant, induces the formation of metHb. mHb in turn can sequester cyanide as cyanomethemoglobin.
Hydroxocobalamin (B12): binds CN-
Sodium thiosulfate: donating additional sulfur to liver rhodanase to enhance metabolism and detox CN- to thioctyanate

Question 16

Methemoglobin

Answer 16

Methylene blue (reducing agent)
Vitamin C

Question 17

Carbon monoxide poisoning

Answer 17

100% O2, hyperbaric O2

Question 18

Methanol, ethylene glycol (antifreeze)

Answer 18

Fomepizole > ethanole, dialysis

Question 19

Opiods: overdose vs. dependence

Answer 19

Naloxone (overdose): opioid inverse AGonist
Naltrexone (dependence): opiod ANtagonist, block euphoric effects

Naltrexone should not be confused with naloxone (which is used in emergency cases of opioid overdose). Using naloxone in place of naltrexone can cause acute opioid withdrawal symptoms; conversely, using naltrexone in place of naloxone in an overdose can lead to insufficient opioid antagonism and fail to reverse the overdose.

Question 20

Benzodiazepines

Answer 20

Flumazenil

Question 21

TCAs

Answer 21

NaHCO3 (plasma alkalinization)

Question 22

Heparin

Answer 22

Protamine

Question 23

Warfarin

Answer 23

Vitamin K, FFP

Question 24

tPA, streptokinase, urokinase

Answer 24

Aminocaproic acid (inhibits plasmin)

Question 25

Theophylline

Answer 25

Beta-blocker

Methylxanthine, for asthma, COPD. Competitive nonselective phosphodiesterase inhibitor, which raises intracellular cAMP, activates PKA, inhibits TNF-alpha and inhibits leukotriene synthesis, and reduces inflammation and innate immunity
nonselective adenosine receptor antagonist, antagonizing A1, A2, and A3 receptors almost equally, which explains many of its cardiac effects

Question 26

Amyl nitrate

Answer 26

For CN- toxicity

Oxidant, induces the formation of methemoglobin. Methemoglobin in turn can sequester cyanide as cyanomethemoglobin.

Question 27

Sodium thiosulfate

Answer 27

donating additional sulfur to liver rhodanase to enhance metabolism and detox CN- to thioctyanate