12: Human Toxicity

Molecules that are of greatest toxicity risk

Small, lipid molecules

Types of molecules that don’t need soap for dermal decontamination

Strong acids and bases → incredibly water soluble!

Best practice for hand PPE

Exam glove over a woven glove

Why doesn’t a normal glove or double-glove work

• Latex/nitrile is not impermeable

• Humidity makes your skin more permeable

Primary risk of tilmicosin exposure

Accidental stick

Syndrome caused by tilmicosin toxicity

Cardiotoxicity

What makes tilmicosin toxicity worse

Epinephrine

Tilmicosin mechanism of action

Depletion of cardiac intracellular calcium

Likelihood of tilmicosin poisoning

Low

Primary risk of chloramphenicol exposure

Topical ointments and sprays

Chloramphenicol mechanism of toxicity in veterinary patients

Bone marrow suppression

Chloramphenicol mechanism of toxicity in humans

Irreversible aplastic anemia

Why is chloramphenicol such a risky exposure

Aplastic anemia is not dose dependent

Drugs that commonly cause allergic reactions

• Penicillin

• Tetracycline

• Aspirin

• Excipients: additives to the drug formulation

• Vaccine adjuvants

Drugs that are harmful to pregnant women

Prostaglandins and corticosteroids

When are prostaglandins a risk for pregnant women

All stages of pregnancy

When are corticosteroids a risk for pregnant women

Late pregnancy → early labor!

Prostaglandins should also not be handled by people with which medical conditions

Asthma or other respiratory problems → PGs cause bronchospasm!

Possible routes of exposure to cytotoxic drugs

• Skin

• Inhalation

• Oral

Principles to avoid risk associated with cytotoxic drugs

• Minimize handling, use a commercial formulation and dose

• Use a trusted compounding pharmacy

• Don’t have the owner mix or break meds

What is also a risk consideration when using cytotoxic drugs

Anything that comes out of the patient may be cytotoxic too!

Parasiticides that are a human risk

OPs, carbamates, and pyrethroids

Veterinary drugs with the potential for abuse

• Barbiturates

• Benzos

• Opiates

• Anabolic steroids

Wildlife sedative that is EXTREMELY toxic to humans

Etorphine

How much etorphine can be lethal in humans

One drop

Situational factors that increase the poisoning risk of etorphine

Often handed under uncontrolled circumstances: in the field in a pressurized dart

Safe practices when using etorphine

NEVER use it alone, and have the antidote handy

Etorphine antidote

Naloxone, IV or IM

Lethal effect of etorphine

Respiratory arrest

Why should you not use diprenorphine as an antidote for etorphine

It is a mixed mu agonist and may aggravate the respiratory depression

Factor that makes xylazine and detomidine a human risk

There is a narrow margin of safety in cases of accidental (or intentional) exposure

Xylazine and detomidine mechanism of action

α-2 agonist → CNS depression, hypotension, bradycardia, convulsions

Antidote for xylazine and detomidine

Atipamezole and yohimbine

How are xylazine and detomidine different

They have different potencies and half lives