(04-12-17) Drug Interactions Flashcards
pharmacodynamic
related to the ACTION of a drug
pharmacokinetic
related to processes by which a drug is absorbed, distributed, metabolized, and eliminated by the body
pharmaceutical
related to mixture of two drugs
what type of LA is good for CV diseased ppl?
Mepivicaine 3%
how do AMIDE LAs work?
- block nerve impulses by inhibiting voltage-sensitive Na+ channels
- prevents noxious stimuli from reaching the brain
where are AMIDE LAs metabolized?
liver*****
what are the pharmacodynamics of AMIDE LAs affected by?
- pH of solution and surrounding tissue
- lipid solubility
- addition of a vasoconstictor
- pKa
what is the absolute medical maximum dose for lido 2% with and without epi?
- with epi : 7mg/kg
- without epi : 5 mg/kg
what is the absolute medical maximum dose for articaine 4% with and without epi?
- with epi : 7mg/kg
- without epi : 5 mg/kg
what is the absolute medical maximum dose for mepivicaine 3% with and without epi?
- with epi : 6.6 mg/kg
- without epi : 5.5 mg/kg
what is the absolute medical maximum dose for bupivacaine 0.5% with and without epi?
- with epi : 3 mg/kg
- without epi : 3 mg/kg
what is the absolute medical maximum dose for prilocaine 4% with and without epi?
with epi : 8 mg/kg
without epi : 8mg/kg
if an LA has 2% concentration, what is the mg/carp?
34 mg/carp
what is clark’s rule?
- it is in reference to CHILDREN
- based on weight in pounds
- max dose = (weight of child in lbs/150)x(max adult dose in mg)
what is the safest LA for children?
2% lido with 1:100k epi
what are the early signs of an LA overdose?
- tachycardia & htn
- seizures
- loss of consciousness
what are the late signs of LA overdose
- bradycardia & HYPOtension
- dec CO
- ventricular arrhymias and death
what is the treatment for mild symptoms of LA overdose?
- temp discontinue procedure and reassure pt
- monitor vitals
what is the treatment for moderate symptoms of LA overdose?
- temp discontinue procedure and reassure pt
- monitor vitals
- supplement O2
- admin valium (IV) for seizure
what is the treatment for severe symptoms of LA overdose?
- temp discontinue procedure and reassure pt
- monitor vitals
- supplemetnal O2
- admin valium
- CPR (call 911)
receptors that cause vasoconstriciton, inc in peripheral resistance, and inc in arterial BP?
alpha 1 receptors
what are the two most commonly used vasoconstrictors and what do they primarily effect?
- epinephrine : A1, B1, B2 effects (is most potent)
- levonordefrin : A1 effects
receptors which, when activated, inhibit the release of norepi
A2 receptors
*agonist = clonidine
receptors which, when activated, inc contraciton and heart rate
B1 receptor
receptors which, when activated, cause vascular muscular relaxation
B2 receptor
what are the benefits of epinephrine?
- vasoconstriction - reduce blood loss
- prolongs actions of LA - limits diffusion
- limits systemic absorption of LA
vasoconstrictors are metabolized and inactivated by what 2 enzymes?
- catechol-O-methyltransferase (COMT)
- monoamine oxidase (MAO)
what are the potential systemic side effects of vasoconstrictos?
- inadvertent intra-arterial injections
- drug-drug interactions
what are the possible issues with combining vasoconstrictors and amphetamines?
- could potentiate clincal effects of epi
- promotes the release of norepi and can block the reuptake of NE
*ex adderall, ritalin, cocaine
what do non-selective beta blockers lead to?
- HTN
- reflex bradycardia
what are the vasoconstrictor interactions between antidepressants and epi regarding tricyclics?
-prevent neural uptake of catecholamine at the adrenergic nerve terminals
- create an exaggerated response to epi at synaptic cleft
- *leads to inc BP and HR
***but most exogenously administered epi is metabolized by COMT
what are the vasoconstrictor interactions regarding an alpha blockade?
- leads to HYPOtension and tachycardia
- more pronounced with levonordefrin than epi at low doses
- “epinephrine reversal”
what do COMT inihibitors do?
- used for parkinson’s disease for pts taking Sinemet
- dec I-dopa metabolism
*EXAGGERATED RESPONSE TO EPI
what are the two market drugs that are COMT inhibitors?
- tolcapone (Tasmar)
- entacapone (Comtan)
the amount of administered epi that reaches the general circulation after LA for dentistry has been hypothesized to be less than what?
the amount of epi releasd in response to the pain and stress of inadequate anesthesia
what is the mg maximum epi dosage for a healthy pt?
0.2mg = 11 cartriges
what are the issues with vasoconstrictors and pts with CVD?
- take vitals prior to injection and 5 minutes post injection
- administer more if vital signs allow
- do not administer more than 0.04mg epi at one time
what is the max epi dosage for a CVD pt?
0.04mg = 2.2 cartriges
what do NSAIDS combine?
- analgsic
- anti-pyretic (fever)
- anti-inflammatory
what 3 things do COX-1 prostaglandins promote?
- gastric protection
- platelet aggregation
- renal blood flow
what does COX -2 prostaglandins promote?
renal blood flow
what are the adverse effects of NSAIDS?
- GI bleeding
- platelet dysfunciton
- renal dysfunction
- CNS issues
- exacerbation of asthma (due to shift to leukotriene pathway)
what is the most common COX-2 selective NSAIDS?
celecoxib (celebrex)
- good anti-inflammation
- concern for embolitic phenomena
- expensive
- not good for 3rds molar pain
what are the possible CV effects with NSAIDS?
- peripheral edema
- dec effect of antihypertensives and diuretics
what put patients at risk for hypoglycemia when they are on NSAIDS?
competition for plasma protein binding sites
bleeding
what is the only NSAID that does NOT put pts at risk for hypoglycemia?
*METFORMIN **
SHE SAID THIS WOULD BE ON TEST FOR SURE
when you combine opioids with ____ you receive excessive sedation?
CNS depressants (xanax) antihistamines (allegra)
when you combine opioids with ____ you receive constipation?
anticholinergic (spiriva)
antidiarrheal (imodium)
when you combine opioids with ____ you receive hypotension?
antihypertensives (hypotension)
what enzyme is need for the conversion of most opioids?
CYP 2D6
*hydrocodone will provide some analgesia w/o the conversion so it is the best to use if pt is deficient
what % of whites, AAs, and asian americans have a deficiency in the CYP 2D6 gene?
- whites : 10%
- AAs : 3%
- Asians : 1%
***hydrocodone will provide some analgesia w/o the conversion so it is the best to use if pt is deficient
what opioid does not need the CYP 2D6 enzyme for conversion of the drug to be metabolized?
hydrocodone
what should be the PRIMARY ANALGESIC USED FOR ALL PTS?
NSAIDS (unless contraindicated)
- ibuprofen 600mg
- tylenol 500-1000mg
why should you as a dentist not have to worry about dependence to opioids?
-tolerance and dependence require at least 2 weeks regular administration and you should only give enough for 3-5 with acute pain
which antibiotics, when used with coumadin, enhance anticoagulation ?
- penicillin (dec vit-K synthesis in gut)
- metronidazole (inhibits metabolism of coumadin)
do antibiotics have an inhibition on oral contraceptives?
yes, tell women to use other BC
tetracyclines inc what _____ levels in the body
lithium
metronidazole mixed with _____ causes severe nausea and vomitting?
ethanol
