Drugs of Abuse/Alcohol Flashcards
Cocaine
- Can be used as local anesthetic or CNS stimulant
- Half-life of 30min-1hr
- Elimination dependent on Liver metabolization to BE and filtration by kidney
- Primary metabolite is benzoylecgonine, found in urine for 3 days follwing use; can be up to 20 days with a chronic user
THC
- Half-life 1 day from single use, 3-5 days chronic use
- Distributes to lipophilic tissue
- Metabolized by Liver to THC-COOH, which is detectable in urine 3-5 days after
- Detected by Immunoassays and GC
Benzodiazepines
- Tranquilizer, causes CNS depression
- Cause respiratory acidosis
Barbiturates
CNS depression
Cause respiratory acidosis
Drugs screened for in urine
- Amphetamines, 2 days
- Barbiturates, 9 days (phenobarbital)
- Benzodiazepines
- THC, clears in 5 days
- Cocaine (Metabolized to benzoylecoginine in 3.5min, test is for BE), 2 days
- Opiates (Morphine)
- PCP, 7 days
- Propoxyphene
- Opiates, 1-2 days
PCP
- Produces stimulant, depressant, anesthetic, and hallucinogenic effects
- Distributes to lipophilic tissue, elimination depends on Liver metabolism, filtered by kidneys
- Detectable in urine for 7-30 days following chronic use
Opiates
Used for anesthetic/sedative properties
Respiratory depressant causing respiratory acidosis
Screening Methods
- All based on Immunoassy
- 20 ng/mL
- Confirmed with GC/MS
Causes of False Neg/Pos in screening
- Cross reactivity with other drugs
- Chemical interferences
- Actual Drug not abused
- Dilution/Substitution
- Adulteration
Adulteration
- Adding water/bleach/Visine/Urinaid/Joy Soap to urine for masking; commonly in THC testing
- Checking for Adulterants, Adulta Check 4
- Regent Test Strips for Nitrate, Glutaraldehyde, Creatinine, pH
False Positives in Opiates
Poppy Seeds
False Positives in Methamphetamine
- Vick’s Inhaler with I-methamphetamine
- Can be used to treat narcolepsy and problems focusing
- Detected by immunoassays and GC
HCG in Sports
- HCG 22 is produced by the placenta
- When injected into males, causes testosterone production and inhibits its shut down (counteracts anabolic steroids)
Codeine Conversion
- Converted to morphine by cytochrome
- 10% people cannot convert due to a genetic polymorphism
EMIT
Drug Ab-enzyme, patient drug replaces enzyme on Ab and starts NADH reaction
ELISA
Drug Ab binds drug and drug conjugate inproportion to patient drug level in sample
FPIA
Drug Ab binds drug and drug-FITC conjugate, changing fluorescence polarization directly proportional to conjugate bound
Pharmacological Actions of Barbiturates
Anticonvulsant, with sedation in most doses except phenobarbital
High doses cause muscle relaxation, overdose causes medullary depression, respiratory arrest, hypotension, and cardiovascular collapse
Drug Groupings based on addiction potential
- I, no known medical use (LSD, Peyote, marijuana, GHB)
- II, Opium, morphine, codeine, oxycodone, amphetamines, barbiturates
- III, barbiturates and narcotics in limited amounts
- IV, benzodiazepines, chloral hydrate, phenobarbital
- V, Antitussives, antidiarrheals in very limited amounts
General Structure of Alcohols
- Methanol, HO-CH3
- Ethanol, HO-CH2-CH3
- Propanol, HO-CH2-CH2-CH3, used as GC standard
- Isopropanol, HO-CH3-CH-CH3, rubbing alcohol
- Ethylene Glycol, HO-CH2-CH2-OH, antifreeze
Alcohol metabolism
- ADH (alcohol dehydrogenase) oxidizes ethanol to acetylaldehyde, then oxidized to acetate by AcDH
- These reactions also reduce NAD+ to NADH
- Aceytlaldehyde and acetate are toxic and cause side effects of alcohol consumption
Adverse Effects of Alcohol
- Loss of NAD+ limits energy production
- LDH (lactate dehydrogenase) is produced more due to increased NADH
- Reduces capacity of liver to deliver glucose to blood
Specimen Requirements
- Venous blood
- Reported in g/dL (%)
- Breath analysis, # grams per 210L of breath (%)
Signs/Symptoms/Diagnosis of Alcoholism
BAC >150mg/dL with no evidence of intoxication, systemic diseases/organ dysfunctions
Systemic Effects of ETOH
- Liver
- Early: replacement of hepatocytes by adipocytes
- Late: CT replaces liver cells
- Vascular: hypertension, arteriosclerosis, hemorrhage, acidosis
- Kidneys: dehydration, high electrolytes, urates
- Muscle/CNS: protein denaturation, low coenzymes
Metabolic Pathway Alteration
Liver damage, shown by liver enzyme elevations, inability to conjugate bilirubin, increased lipogenesis and ketone body synthesis, decreased glycolysis, glucogenesis and protein biosynthesis
Predisposition to Alcoholism
- ADH deficiency
- Genetics, AcDH deficiency in Asian pop.
- Gender, Females can lack ADH
- Body mass/size, smaller people affected sooner
- Drinking history
Alcohol reactions with Drugs
- Increase drug absorption in GI
- Liver enzymes that degrade drugs may speed up catabolism of drug
- May increase ratio of free:bound drug
Ca Legal Limit
0.08g/dL
Zero Order Elimination (alcohol)
10mL ethanol oxidized per hour
Analytical Methods for BAC
- Enzymatic, enzyme + NAD+ and ADH gives acetaldehyde + NADH
- Kinetic, ethanol oxidase and Clark Electrode to monitor change in PO2
- GC, differentiates and quantifies different alcohols
- Osmolality and Osmolar Gap
- Osmolar gap >10, ethylene glycol is likely
- Osmolar Gap = measured osmolality – calculated osmolality
- Calculated osmolality = 1.86(Na) + Glucose/18 + BUN/28 + 9
Osmolar Gap Calculation
Osmolar Gap = measured osmolality – calculated osmolality
Calculated Osmolality Calculation
Calculated osmolality = 1.86(Na) + Glucose/18 + BUN/28 + 9
Liver Function Tests
- Bilirubin
- AST
- ALT
- ALP
- GGT
Antifreeze Biotransformation to toxic metabolite
Converted to Oxalic Acid crystals which lead to renal failure by causing metabolic acidosis
Ethylene Glycol
- Distinguish from Ethanol with Blood Test
- Diagnosed by metabolic acidosis, anion gap, osmolar gap, urinary calcium oxalate crystals
- General Lab Results: pH 7.3, pCO2 13, CO2 6.2, osmolality 314, anion gap 33
- Treatment: ethanol IV and 3 doses fomepizole at 10mg/kg
Anion Gap
Na – [C + HCO3]
[Na + K] – [Cl + HCO3]
Outside range indicates Lab error or metabolic acidosis
Methanol Effects
Severe acidosis, blindness, and death upon conversion to formaldehyde then formic acid
Isopropanol Effects
Similar to Ethaonl, but persist for longer because it is metabolized to acetone
Ethylene glycol Effects
Severe metabolic acidosis and renal tubular damage
(Meth)Amphetamine
May be used to treat narcolepsy and disorders involving focus
