toxicology 2

Question 1

Arsenic mech of action

Answer 1

Toxicodynamics: interfere with enzyme activity & cell signal transduction, oxidative stress, alter gene expression

Question 2

As Acute toxic effects:

Answer 2

GI: N/V/D, abdominal pain, diffuse capillary leak & fluid loss → hypotension, shock, death
Cardiopulmonary: Pulmonary edema, ventricular arrhythmias (promptly or delay of several days), pancytopenia
CNS : Delirium, encephalopathy, coma, neuropathy (2-6 weeks onset) → proximal muscles & respiratory failure

Question 3

As Chronic toxic effects:

Answer 3

Fatigue, weight loss, weakness
Anemia, GI complaints, peripheral neuropathy
Hyperpigmentation & hyperkeratoses of skin on hands & feet
Cancer: Lung, skin, liver

Question 4

After inhalation, CO

Answer 4

avidly binds to hemoglobin → carboxyhemoglobin, 230-270 X > than O2, Also, ↓ unloading of O2 to other tissues by ↑ O2 affinity to hemoglobin at other O2 binding sites, Further ↓ O2 delivery

Question 5

CO toxic effects

Answer 5

Hypoxia: CNS & heart especially sensitive

Clinical presentation: HA, dyspnea, drowsiness, lethargy, confusion, Higher doses can cause seizures, coma & death

Question 6

HCN MOA

Answer 6

After absorbed into the body, Inhibits cytochrome a3 mediated electron transfer, Which prevents energy production by oxidative phosphorylation
Death can occur quickly because of lack of ATP production

Question 7

N-acetylcysteine

Answer 7

Antidote for acetaminophen overdose, Acetaminophen → liver damage by CYP-mediated bioactivation, N-acetylcysteine inactivates the reactive metabolites, Administer within 8-10 hours

Question 8

Flumazenil

Answer 8

treats Benzodiazepine, Silica, Asbestos toxicity; GABAA receptor antagonist, Side effects → seizures, withdrawal, Shorter t1/2

Question 9

O2 treats

Answer 9

Copper toxicity, CO toxicity, Silica & Asbestos tox

Question 10

Naloxone treats

Answer 10

opiod tox (μ receptor antagonist)

Question 11

Atropine treats

Answer 11

Organophosphate (malathion) & carbamate (aminocarb) insecticides tox, Gamma-hydroxybutyrate tox, Silica, Asbestos tox; (musc receptor antagonist)

Question 12

Penicillamine treats

Answer 12

silica, asbestos tox, Cu tox

Question 13

Deferoxamine treats

Answer 13

iron tox (Fe chelator for absorbed Fe which promotes excretion in urine & feces)

Question 14

Na Thiosulfate treats

Answer 14

Silica & Asbestos tox, HCN tox (Sodium thiosulfate converts cyanide into less toxic thiocynate which is renally eliminated)

Question 15

Fomepizole treats

Answer 15

Silica & Asbestos tox, Alcohol tox (Methanol, Ethylene glycol) (Fomepizole inhibits alcohol dehydrogenase, Renal elimination of parent compound)

Question 16

Succimer treats

Answer 16

Pb tox, Hg tox

Question 17

Dimercaprol treats

Answer 17

Pb tox, Hg tox, As tox, Cu tox (forms a coordinated bond with cationic metal & the complex renally excreted)