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28 Cards in this Set
- Front
- Back
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List 4 drugs in dentistry that may contribute to DIs |
Antibiotics, LA and epi, sedatives, analgesics |
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List 6 NSAIDs interactions |
1. CVS meds (ACE inhibitors, diuretics, beta blockers, digoxin) 2. CNS meds (lithium, SSRI) will cause more bleeding 3. Anti-coagulants (bleeding) 4. Methotrexate (lower doses for arthritis are ok, but higher doses for cancer will yield DIs) 5. Acetaminophen 6. Other NSAIDs 7. more... |
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Misoprostol (Cytotec) |
Prevents gastric bleeding, used as an intentional drug interaction with NSAIDs. Absolute contraindication during pregnancy (abortion drug) |
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List 5 drugs with low therapeutic index are are thus more susceptible to negative DIs |
Lithium, digoxin, carbamazepine, warfarin, cyclosporine |
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List 4 pharmacodynamic effects that can cause DI |
1. Antagonism/competition (ex: Penicillin + tetracycline) 2. Unexpected drug effect (ex: disulfuram + alcohol) 3. Summation (ex: opoid analgesic + halothane GA) 4. Synergism (ex: acetaminophen + ibuprofen) |
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What systemic effects can epi in LA cause? |
Vasoconstriction in mucous membranes (local) due to alpha-1 stimulation. Increased HR due to beta-1 stimulation. Vasodilation in skeletal muscles due to beta-2 stimulation. |
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List 4 drugs that can interact with LA epi |
Beta blockers, TCAs, GA, Cocaine and amphetamines |
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How might LA epi and beta blockers interact? |
A systemic dose of epi will target alpha receptors only (not beta), and may cause unopposed constriction. Hypertensive rx (increase in BP) |
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How might TCA and local epi interact? |
Increase in HR and BP, abnormal heart rhythms |
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How might cocaine/amphetamine interact with local epi? |
May cause increase in BP, cardiac arrhythmia. Additive toxicity. |
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How might local epi and GA interact? |
Primarily with halothane, possibly isoflurane. May lead to cardiac arrythmia. |
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What are 4 pharmacokinetic mechanisms of drug interactions? |
Absorption, distribution, metabolism, excretion |
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How might omeprazole (proton pump inhibitor) interact with other drugs? |
Changes the pH of GI, which can affect ionization and thus absorption of another drug |
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How might chelation cause drug interactions? |
By forming complexes (ex: tetracycline + Calcium ions) the drug isn't absorbed |
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How might metoclopramide (GI drug) cause drug interactions? |
Absorption changes of drugs. Increases gastric emptying rate and results in earlier and higher peak concentrations for drugs that are rapidly absorbed in upper small intestine |
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How might opioids affect the absorption of other drugs? |
Slows gastric emptying and intestinal motility- slower absorption of drugs and lower peak drug concentrations, later times of peak concentration |
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How can broad spectrum antibiotics change the absorption of other drugs |
Changes in bacterial flora. Example: 40% of digoxin is metabolized by intestinal flora. Broad spectrum antibiotics can cause increased digoxin concentration and toxicity |
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Displacement of drugs is usually not clinically significant, except in which 3 cases? |
1. Administering of a displacing drug is started at high doses during chronic therapy with a displaced drug. 2. The volume of distribution of displaced drug is small. 3. The response to the drug occurs faster than redistribution of enhanced elimination. |
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Drugs that are CYP inducers would affect another drug how? |
CYP inducer would increase the metabolism of the other drug, decreasing the drug action. Ex: Warfarin + Rifampin (antibiotic and CYP inducer) = decreased warfarin (increased coagulation) |
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Drugs that are CYP inhibitors would affect another drug how? |
By inhibiting the CYP, the other drug will not be metabolized and will increase. Ex: Warfarin + Ketoconazole (antifungal and CYP inhibitor) = increased warfarin (increased bleeding) |
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How do Phenytoin and theophylline interact? |
Enzyme induction- phenytoin increases hepatic metabolism of theophylline, leading to decreased levels |
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How do St. Johns Wort and cyclosporine A interact |
SJW induces 3A4 and 1A2, decresing cyclosporine levels (big risk for a transplant patient who takes SJW) |
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How does grapefruit juice interact with other drugs? |
CYP3A4 inihibitor- increased levels of Ca channel blockers, cyclosporine, tergenadine, midazolam and more |
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Why do enzyme inducers have slow onset? |
requires protein synthesis (2-3 weeks) |
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Why do enzyme inhibitors have a fast onset? |
May be due to competition at binding site (12-24 hours) |
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How do enzyme inhibitors and inducers affect pro drugs? |
Inhibitor will decrease drug. Inducers will increase the drug |
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A patient who is a rapid metabolizer of CYP2D6 will have what effect? |
Codeine will produce excessive morphine (why?) |
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Give a prominent example of tubular secretion competition |
Pobenecid and pencillin- increased antibiotic serum concentrations. Probenecid decreases the kidneys' ability to remove penicillin from the body |
