03 Cocaine Flashcards
what plant does cocaine come from?
found in the leaves of the coca shrub
cocaine is (almost) the only local anesthetic that…
causes constriction rather than dilation of the blood vessels
-“nerve conduction blocks” thus it doesn’t need any epi to keep the anesthetic localized
duration of cocaine anesthetic
very short duration of action
toxic above what dosage?
30 mg, and addictive if consume systemically
what are the different routes of administering cocaine?
IV, smoking, snorting, chewing (in order of effectiveness), it does have good transmucosal absortion
how is it made?
coca leaves–> chemical extraction–> cocaine paste (not water soluble)–>oxidation, acids–> cocaine HCL (this is what is snorted or IV)—>baking soda—>”crack cocaine”, cocaine free base precipitates, Evaporation, broken into rocks for resale
why is cocaine smoked?
all the blood passes thru the lungs
- 15% of cardiac output from left ventricle goes to the brain
- peak brain concentrations within 6-8 seconds
cocaine is broken down where and how
in the liver by cholinesterase, broken down into Benzoylecgonine (BEG) which is the major urinary metabolite, this is still present for up to 10 days
- the second metabolite is Ecgonine or methylecgonine (MEG) and Benzoic acid
what does MEG do?
depresses the heart by muscarinic receptor activation
cocaine does what to neurotransmitters?
blocks neuronal transporter for NE, DA, and 5-HT (serotonin)
-it blocks reuptake
mechanisms of Cocaine: ANS
- Indirect agonist: blocks uptake-1 protein on noradrenergic terminal, leads to higher NE levels in the synaptic cleft
- local anesthetic: blocks Na+ channels
what does cocaine do to the heart?
- tachycardia and increase cardiac output (Beta-1)
- arrhythmias in some individuals (beta-1)
- local anesthetic effect (depresses heart)
- MEG from “crack” also depresses cardiac fn
effect of cocaine on organ systems/vasculature
- vasoconstriction (alpha-1)=hypertension
- myocardial infarction: vasospasm of coronary arteries, may occur in minutes or up to 18 hours later
cocaine effect in CNS
- indirect agonist
- blocks uptake-1 protein on NE, DA, and serotonergic terminals
- leads to higher NE, DA, and 5-HT levels in synaptic cleft - local anesthetic
- blocks Na+ channels
- may cause seizures
death from cocaine use can come from:
- cerebral infarction or vasospasm
- intracranial hemorrhage
sign common to cocaine and cocaine free-base (or “crack”) abuse: acute intoxication
- impaired judgment, hyper-vigilance, agitation, paranoia, with prolonged use: “toxic psychosis” resembling schizophrenia or mania
- hypertension and tachycardia (significant)
- “crack” signs may last 2 hr
- “snorted” cocaine signs may last 4-6 hours
signs common to cocaine and cocaine free-base (or “crack” abuse: withdrawal craving:
- intense desire for drug
2. depression, fatigue, muscle pain, tremors, hypersomnia, they may feel really sick
Signs common to CHRONIC cocaine intoxication:
- “snorted” cocaine: chronic rhinitis (sniffing), sinusitis, ulceration (or degeneration) of nasal septum.
- cocaine users also commonly brux - injected cocaine (10% incidence)
- needle tracks
free-base cocaine
the most processed, it is what is smoked, not snorted or IV
signs common to chronic cocaine free-base “crack” abuse
- laryngeal burns, hoarseness, difficulty swallowing
- products of pyrolysis: brown stains on mucosal surface/brown particles in sputum and on teeth
- stridor (high-pitched noisy respiration)
- “crack” lung: (build up of fluid in lung)diffuse alveolar infiltrations on x-ray, pulmonary edema, scarring, chest pain, dyspnea
signs of cocaine use in oral cavity
they often brush really well and cause gingival recession, even if their dental care is poop
- intense bruxism, TMJ pain possible
- for those who brush: unilateral abrasion of cervical margins of maxillary and mandibular arches due to vigorous brushing (left-side for right handers and visa versa)
- post-extraction bleeding times may be prolonged
- can get perforations in palate
if patient uses cocaine, how do you treat them
- send them to emergency room, or
- make sure cocaine hasn’t been used in the last 4-6 hours
dental local anesthetic and cocaine users:
- local: inadvertent i.v. injection of drug can directly depress the heart (blockade of TTX-R Na+ channel)
- Cocaine: sympathomimetic effects; its local anesthetic properties will have additive effects with L.A on the heart
- Methylecgonidine (MEG): depresses heart through muscarinic receptor activation
what type of LA should be avoided and why
ester-linked LAs: allergic reactions (1-3), seizures(4-5)
- cocaine metabolite-benzoic acid ester
- para-amino benzoic acid derived LAs
- benzoic acid from both sources may induce allergic reactions, further complicating the situation
- avoid using procaine HCL
- may augment pro-convulsive effects of cocaine
so avoid using LA with____ and for long procedures consider using____
epi and preservatives, mepivacaine
conscious sedation:
benzodiazepines, but don’t use midazolam (versed)
propofol for
conscious sedation, nitrous oxide is safe for all office dental procedures for cocaine abusers
ketamine
avoid it….
