Minor/ Unique Metabolites 7 1 Sun Flashcards
What kind of pathways can drugs undergo
Oxidative, hydrolytic, and conjugated
What does metabolism do to drugs
Alters chemical structure leading to the production of multiple metabolites
Minor metabolites, in some cases may be low conc and account for very little of the dose and may be overlooked
May increase the during of action/effect of a drug due to increased half-life, enhanced pharmacological activity
Metabolite may also increase the toxicity of the drug
Halogenated hydrocarbons toxicity is mostly due to
biotransformations products
Methylene chloride metabolism (two routes)
Cytochrome P-450 dependent route leading to carbon monoxide
P450 2E1
Glutathione S-transferase route leading to formaldehyde and formic acid
Methylene Chloride case
20-year-old art student using MeCl2 in poorly ventilated room
Developed N/V and severe headache
Left room after 1 hour
Felt dizzy and “unwell”
Shortly lost consciousness
Transported to ED
Arrived ED conscious but disoriented
Cherry-red coloring of skin and mucosa
Admit COHb was 50%
O2 therapy [60% 4L/min] at 12 hours 20% COHb
Carbon monoxide half-life
Room air: 3-4 hours
100 O2: 30-90 minutes
MeCl2 requested in tissue and slowly released
CO in circulation for a prolonged period
Methoxyflurane
Anesthesia use associated with renal dysfunction in some patients
Metabolites of methoxyflurane nephrotoxic
Fluoride
Oxalate
Renal biopsies show oxalic crystals
Elevated urine oxalate concentrations
Selegiline- what is it used for
Tx early-stage Parkinson’s disease, depression, and dementia
Selective irreversible MAO-B inhibitor
Larger doses lose specificity and inhibit MAO-A
Selegiline metabolism
Partly metabolized to L-meth/amp
L stereoisomers are significantly less psychoactive and have low abuse potential in contrast to D-isomers
Metabolic pathway may cause positive drug test for amphetamine and/or methamphetamine
