Toxicology Flashcards
What is a poison?
A substance that is physiologically harmful when admin. to a living organism
What is the relationship of duration of exposure and dose with toxicity?
There is a positive relationship of both principles with toxicity
What is the LD50?
The lethal dose at which 50% of animals tested die
-legally a poison
What is the TI (Theraputic index)?
LD50/ED50
The larger the number, the safer the drug
What is the TI of Benzos vs Barbiturates?
Benzos have a high TI and Barbiturates have a low TI
What is the ALD
Average lethal dose
What should be asked in Primary care if poisoning has occurred?
What was the dose? How much?
How long ago did they ingest it?
What is the clinical management of poisoning?
Support vitals (ABCs) Reduce/Remove the drug from the body
What is unique about treating an unconcious patient?
General antidotes -glucose/insulin(Diabetic shock/hypoglycemia) -naloxone(narcotic OD) Tx emergent conditions ID the Poison
What is the procedure to induce emesis?
Mechanical
Apomorphine
Syrup of Ipecac
What are the contraindications of inducing emesis?
Petroleum hydrocarbon solvent (chemical pneumonitis)
Caustic acid or alkali agent
seizing or comatose Pt
Why is activated charcoal a good option?
Admin orally in water
- very arge Surface area allows for binding of organic toxicants which prevents absorption
- often induces emesis
What are cathartics?
Promotes rapid movement and elimination of poison through GI tract
What are rhe antidotes that chelate Organophosphates?
Organophosphates
-Pralidoxime-Admin with Atropine to block antimuscarinic effects of PNS
What are rhe antidotes that chelate Cyanide?
CNS and Cardiac tissue are esp affected
produce death in 1-15 min
Admin: Amyl nitrate, Na Nitrate, Na Thiosulfate with O2
What are rhe antidotes that chelate Botulinum Toxin?
ABCs Trivalent anti-toxin, emesis, charcoal, lavage,
What are rhe antidotes that chelate Heavy metals?
Chelators(BAL, EDTA, DMSA, DMPS, Ca EDTA) complex with Hg, Pb, As, Fe, Ag making them inert and increasing renal excretion.
What is the Antidote DMSA?
Treats As, Hg(mercury), Pb(lead) poisoning
Dosage: Adults, PO for 5 days
Children, total of 19 days
What is the Trivalent antitoxin for botulinum A, B, E
.
What is the antidote for Cyanide?
Inhaled Amyl nitrate
IV Na Nitrite (reacts with Hb to form mHb)
IV Na Thiosulfate(reacts with mHb to give thiocyanate and hemoglobin
What is the antidote for Alcohol(ethylene glycol, methanol, isopropylOH)
MethOH into Formaldehyde and formic acid by ADH
Hemodialysis as adjunct can be lifesaving withMethOH and ethylene glycol
What is the action of Fomepizole
Blocks the Ez that converts EG ad MOH to toxic compounds***
What is the Tx for CO poisoning?
Artificial resp. withpure O2 to promote displacement of CO, hyperbaric O2 if symptomatic
What are the S and S of CO poisoning?
Cherry red lips and gums
Severe headache, weakness, dizziness
What are the features of Warfarin overdose?
Hemoptysis, excessive, bruising, bleeding from nose, gums and urethra/anus
High INR
Tx For warfarin OD?
Vit K
What is the Tx of Opioid OD?
Naloxone- Fast acting (45 min)
Naltrexone- Long acting to maintan effect
What is the Tx of Methemoglobinemia?
Cannot transport oxygen
Tx is Methylene Blue- Direct chemical reduction methemoglobin to hemoglobin
What are Toxidromes?
Certain symptoms that are charicteristics of certain poisonous agents
Knowing the toxidromes can help you make fast decisions in emergent situations
What are the sympathomimetic (CNS stimulants) toxodromes?
CNS-agitation, hallucinations, paranoia Resp pupils- Mydriasis(dilated pupils) Other, HTN, Tremor, Hyperthermia, seizure Drugs- Cocaine, Meth, PCP
What are the sedative/hypnotic toxodromes?
CNS-coma Resp- dec pupils- miosis or mydriasis Other, hypothermia Drugs- alcohol, Barbiturates, Benzos
What are the opioid toxodromes?
CNS-coma Resp-dec pupils- pinpoint Other, Opiate Triad: Drugs- Opiates, morphine, codiene
What are the anticholinergic toxodromes?
CNS-agitation Resp- pupils- dilation Other, Fever, dry skin, flushing, urinary, retention Drugs- anticholinergics, antidepressants
What are the cholinergic toxodromes?
CNS-coma
Resp-
pupils- ppp
Other, SLUDE(fasiculation, incontinence, salivation, wheezing, lacrimation, bradycardia)
Drugs- organophosphates, nicotene, insecticides
What are the tricyclic antidepressants toxodromes?
CNS-coma, agitation
Resp-
pupils- mydriais
Other, dysrhythmia, convulsions, hypotension(alpha blockade)
Drugs- TCA’s, amitriptiline, imipramine, desipramine
What are the tricyclic antidepressants toxodromes?
CNS-up or down Resp- increase or normal pupils- Other, diaphoresis, tinnitis, agitation, alkalosis (ea), acidosis(lt), hyperpyrexia Drugs- ASA, ASPIRIN, other salicylates
