Session 25: Treatment/Prevention of Toxicity

In class final will be May 15 at 10:30 AM.

So how do we go about preventing or treating toxicity?

For the individual:

1.	Avoid exposure

2.	Minimize dosage

3.	Maximize elimination (e.g., modify urine pH, often alkalinize)

4.	Block circulation and absorption of toxicant (chelators, antibodies, charcoal, clays)

5.	Apply antagonists (for specific molecular targets)

6.	Promote repair

(Note that antibodies may be introduced by passive, e.g., antivenins, or active vaccinations.)

For the environment:

1.	Modify chemical use and disposal

2.	Institute regulations

3.	Minimize releases or exposures

4.	Isolate polluted/contaminated areas/populations

5.	Institute remediation procedures

Note that Education plays a big role in avoiding both individual and environmental exposures as well as in minimizing dosages. Foreknowlege allows comparative risk evaluations to be made. Regulations help codify the knowledge base and provide guidelines for toxicant handling procedures. They externalize comparative risk evaluations. Education also allow formulation of appropriate response information and the description of pertinent treatments to handle detoxication.

What about treatments in the clinical sense?

Procedure usually involves the following steps:

1.	Take a complete history of the intoxication (acute, chronic, contributing conditions)

2.	Evaluate the subject's condition, identify the poison and dose, if possible

3.	From databases or references determine the expected pharmacokinetics for clearance (How long will elimination take and what effects can be expected in the dose range involved?)

4.	If the intoxication is acute and recent, act to decrease the dosage.

5.	If minimal risks are involved, provide medical support with minimal interventions.

6.	If there is a potential for extensive morbidity or mortality undertake active interventions:

•	For oral exposure: dilute the stomach contents, pump out the stomach, give one or more cycles of activated charcoal, provide antidotes or antagonists as appropriate.

•	For blood exposure: provide chelators or appropriate antibodies, or perform dialysis or transfusion as required.

•	Since dermal and respiratory exposures normally pass through the blood the only palliative measures that apply beyond the treatments suggested for blood exposures are removing the subject from the exposure source and doing a thorough washing with appropriate detergents of the exposed dermal surfaces.