pharmacology and toxicology science and policies
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Pharmacology and ToxicologyScience and Policies
Nursing and Chemical Policies
Barbara Sattler, RN, DrPH, FAANUniversity of Maryland School of Nursing
Pharmacology vs. Toxicology
Pharmacology is the scientific study of the origin, chemical nature, effects and use of drugs.
Toxicology is the science that investigates the adverse effects of chemicals on health.
Dose
Pharmacology
Dose refers to the amount of drug absorbed from an administration
Toxicology
Dose refers to the amount of chemical introduced into a biological system
Administration
Pharmacology
Administration of a drug can be one time, short or long-term.
ToxicologyExposure is the
actual contact that a person has with a chemical. It can also be one time, short or long-term.
Dose-Response Curve
Pharmacology
Graphically represents the relationship between doses of a drug and the response elicited.
ToxicologyDescribes the
relationship of the body’s response to different amounts of an agent such as a drug or toxin.
Distribution, Metabolism, & Excretion
Pharmacology and Toxicology (ADME) Absorption is the amount of a substance that enters
the body Distribution: Organs/Tissues/Cells that are reached Metabolism: Chemical Transformation
/metabolites Excretion: Elimination/Persistence
Routes of Administration or Exposure
PharmacologyRoutes of
Administration: oral, IM, IV, inhalation, dermal, ocular, etc.
Toxicology
Routes of Entry: ingestion, inhalation, dermal absorption, ocular, etc
Pharmacology vs. Toxicology
In pharmacology there are therapeutic responses to drugs (desirable) and side effects (undesirable).
In toxicology only the negative health effects are of concern.
Potency vs. Toxicity
Pharmacology
Potency refers to the relative amount of a drug required to produce the desired response.
ToxicologyThe toxicity of a
chemical refers to the relative amount it takes to elicit a toxic effect compared with other chemicals.
Definition of Toxicity
Toxicity refers to the ability of a chemical to damage an organ system, to disrupt a biochemical process, or to disturb an enzyme system.
Three Types of Effects
Additive: the sum = the whole
Antagonistic: one reduces the effect of the other
Synergistic: one enhances the other’s effect
Cummulative exposures occur when multiple sources of one or more toxic chemical exist.
For example, in a single day, we can be exposed to pesticides in our homes, workplaces, and outdoors, as well as from the food we eat.
Mixturesand Multiple Cummulative
Exposures
Little is known about the toxic effects of multiple hazardous chemicals.
Biological Monitoring
Pharmacology
Bio-monitoring is done for some drugs: For example:
Clotting time is monitored for patients on coumadin.
Actual drug levels are measured for some drugs.
Toxicology
Bio-monitoring is done for some toxic exposures such as blood lead levels or metabolites of chemicals (biomarkers).
Index vs. Threshold
Pharmacology
Therapeutic Index is the relationship between a drug’s therapeutic effect and its adverse effects.
Toxicology
Threshold levels refers to the amount of a substance necessary to cause a response in the body.
Pharmacology/Toxicology
The effects of drugs and hazardous chemicals can be immediate (acute), long-term (chronic), or can present after a latency period.
Drugs are taken voluntarily and often under the supervision of a licensed health care provider.
Hazardous chemical exposures are most often involuntary.
Host Factors
Host factors must be considered for therapeutic drugs or hazardous chemicals. Factors such as age, genetics, weight, drugs that a person may be taking, pregnancy status, and others may impact the therapeutic or toxic effect of a drug or chemical.
Children's Special Vulnerabilities
Children… Are still developing and may have immature (more
sensitive) biological systems. Eat, breathe, and drink more per body weight than adults Eat a smaller range of foods (greater dairy and fruit/fruit
juices) Behave in ways that may place them at greater risk for
exposure Hand-to-mouth exploration Playing on the floor/ground
Regulatory Processes:Pre-market testing
The regulatory process by which a drug comes to the market includes several stages of testing, including both animal and human testing.
There is no requirement for pre-market testing of chemical products that are not foods, cosmetics, or pesticides. No original testing is required.
Toxicology Resources
Drugs Grateful Med (PubMed) OSHA:
http://www.osha.gov/dts/osta/otm/otm_vi/otm_vi_2.html
NIOSH: http://www.cdc.gov/niosh/docs/2004-165/
PDR Poison Control Centers
Hazardous Chemicals NLM Toxnet:
http://toxnet.nlm.nih.gov/ ATSDR Toxfaqs:
http://www.atsdr.cdc.gov/toxfaq.html
TRI Data: www.scorecard.org
HCWH: www.noharm.org OSHA: http://www.osha.gov/dts/osta/otm/otm_vi/otm_vi_2.html
New Evidence of Exposures
CDC “Body Burden” studies (NHANES) The “Egg” Study EWG “Cord Study”
Nursing Survey of workplace chemical exposures
If chemicals act like drugs, including causing physiologic changes (even at very low levels), shouldn’t they be regulated like drugs?
How can we exert our leadership in this emerging arena
?
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