Introduction to Toxicology Flashcards
study of poisons
Toxicology
Four major disciplines within Toxicology
- Mechanistic
- Descriptive
- Forensic
- Clinical toxicology
to assess the degree of exposure of poisoned individuals
Mechanistic toxicology
“Risk assessment”
Descriptive Toxicology
elucidates cellular and biochemical edfects of toxins
Mechanistic toxicology
uses the results from animal experiments to predict what level of exposure will cause harm in humans
Descriptive toxicology
primarily concerned with the medico legal consequences of toxin exposure
Forensic toxicology
establishing and validating the cause of death
Forensic toxicology
the study of interrelationships between toxin exposure and disease states
Clinical toxicology
emphasizes not only diagnostic testing but also therapeutic intervention
Clinical toxicology
commonly used analgesic drug
acetaminophen
overdose of acetaminophen is associated with what condition
severe heptotoxicity
It is bound with high affinity to various proteins, resulting in low free fraction
Absorbed acetaminophen
how is acetaminophen eliminated
- hepatic uptake
- biotransformation
- conjugation
- excretion
Pathway of major concern in acetaminophen
hepatic mixed-function oxidase system
Explain the hepatic mixed-function oxidase system
- acetaminophen first transformed to reactive intermediates
- which are then conjugated with reduced glutathione
What does free radicals do to the cell?
It causes toxic effect to the cell that leads to
NECROSIS OF THE LIVER
how many days in average adult is acetaminophen detectable?
3-5 days
Who is more susceptible to acetaminophen?
Alcoholic patients
This eliminates free radicals that can cause cancer
Glutathione
Why is alcoholic patients susceptible to acetaminophen toxicity?
Because heavy consumers of ethanol metabolize acetaminophen at a more rapid rate than average —–> more rapid formation of reactive intermidiates and increase possibility of depleting glutathione
Example of Acetaminophen commonly used by patients
paracetamol
What is other name of aspirin?
acetylsalicylic acid
Common use of Aspirin
Analgesic
Antipyretic
anti-inflammatory drug
Function of Aspirin
decreases thromboxane and prostaglandin formation through inhibition of cyclooxygenase
Drug Classification of Aspirin
Anti-inflammatory drug
What TDM stands for? And what is it ?
It stands for Therapeutic drug monitoring
Acetaminophen and salicylates ate included here because they can be drugs of abuse if higher dosage was used
Other actions of Aspirin
- inhibits Kreb’s cycle
- can cause dehydration due to vomiting
Acetylsalicyclic acid is associated with what condition
Metabolic acidosis
Reye’s syndrome
childhood viral infections - varicella and influenza
It is the direct stimulator if respiratory center
Aspirin
excessive salicylate ingestion is associated with what condition?
Metabolic acidosis
result of salicylates inhibiting the Kreb’s Cycle
excess conversion of pyruvate to lactate
result of salicylates stimulating mobilization and use of free fatty acid during high levels of exposure
excess ketone body formation
Treatment for overdose of Salicylate
neutralizing and eliminating excess acid
maintaining electrolyte balance
Methods for quantitative determination of salicylate in serum
GC or liquid chronatography methods
immunoassays
Chromogenic assays (Trinder reaction)
It provides the highest analytic sensitivity and specificity for salicylate determination in serum
GC or liquid chromatography
-but no clinical use because of equipment expenses and technical difficulty
most common method for the determination of salicylates
Trinder Reaction
Method that reacts salicylate with ferric nitrate to form a colored complex
Trinder reaction
Therapeutic drugs used for narcolepsy and attendtion deficit disorder
Amphetamine and Metamphetamine
Effects of acetaminophen and methamphetamine
- Initial: increased mental and physical capacity along with a perception of well-being
- restlessness
- irritability
- psychosis
effects of Chronic use of Amphetamine
Tolerance and psychological dependence
Laman term for amphetamine
Shabu
Result of oversosage of amphetamine
Hypertension
Cardiac arrythmias
Convulsions
Possible death
compounds chemiclly related to amphetamine
Ephedrine
Pseudoephedrine
Phenylpropanolamine
screenig procedure of amphetamine
immunoassay systems
Done to identify amphetamine abuse
analysis of urine for the parent drug
Confirmation of immunoassay-positive test of Amphetamine
Liquid chromatography or GC
Specimen for drugs of abuse and the type of test
Urine — Qualitative (presence or absence only)
Specimen for TDM and type of test
Blood —– Quantitative
how high
illicit amphetamine derivative
Methylenedioxymethylqmphetamine / ecstasy
It has high potential for abuse
Ecstasy
Circulating half - life of Ecstasy
8-9 hours
How is Ecstasy eliminated in the body?
majority by hepatic metabolism
20% is eliminated unchanged in the urine
Onset of effect and duration of ecstasy
onset of effect: 30-60mins
duration: 3.5 hours
Effects of ecstasy
- Hallucinations
- Euphoria
- Empathic and emotional responses
- increased visual and tactile sensitivity
Give 5 adverse effects of Methylenedioxymethylamphetamine
- Seizures
- Renal failure
- Impaired memory
- Tachycardia
- Violent behavior
Reference method for the quantitation of acetaminophen
High-Performance Liquid Chromatography (HPLC)
Most common analytic
method used for serum acetaminophen determination
Immunoassay - Competitive enzyme or fluorescence polarization
Methods that provide the highest analytic sensitivity and specificity for determination of salicylates
Gas Chromatography and Liquid Chroamtography
Chromogenic Assay which reacts salicylate with ferric nitrate to form a colored complex
Trinder reaction
Common immunoassay method used for salicylate
Trinder reaction
Commonly used screening procedure for amphetamines
Immunoassay
commonly used for the confirmation of amphetamines
Gas Chromatography and Liquid Chromatography
used for further analysis and confirmation of Methylenedioxymethylamphetamine
GC/MS
how should specimen be collected and what to remember
Slightly open door
Ph
Creatinine should be positive
