PC 707 CORE MAIN EXAMINATION QUESTIONS
AND ANSWERS SURE A+
✔✔Competitive antagonist - ✔✔Any pharmacologic antagonist that competes with the
binding of agonists at the binding site.
typical of drugs that bind reversibly to the receptor
inhibition can be overcome by increasing the concentration of the agonist to achieve the
same maximal effect
✔✔drugs that decrease renal clearance - ✔✔acetaminophen
anti-arrhythmics
anticonvulsants
anti-depressants
anti-psychotics
beta blockers
theophylline
warfarin
benzos
✔✔Non-competitive antagonist - ✔✔Any pharmacologic antagonist that binds to a site
on the receptor other than the agonist binding site. The Agonist will be able to bind but
not able to activate due to the presence of the antagonist
typical of drugs that bind irreversibly or allosterically to the receptor; this is a drug that
prevents the agonist at any concentration from producing a maximum effect on a given
receptor
✔✔Examples of chemical Antagonists - ✔✔Digibind for Digitalis
Protamine for Heparin
✔✔Chemical AnTagonist - ✔✔binds directly to the agonist, not the receptor, and
deactivates the agonist
"CAT attacks an agonist"
,✔✔Physiologic antagonist - ✔✔drug or chemical that has an opposite effect through
different physiologic pathways.
They work on separate receptors to cause opposite physiologic effects
ex. glucocorticoid hormone can increase BG
insulin would oppose the action
---act on distinct receptor-effector systems
✔✔Classic Example of a physiologic antagonist - ✔✔Epinephrine given to counter act
the effects of Histamine and prevent vascular collapse.
✔✔Metabolism (biotransformation) - ✔✔A process that changes one chemical into
another usually through the use or production of energy. In the case of drugs this
usually takes place in the endoplasmic reticulum of the cells in the liver via enzymatic
processes.
prepares for excretion
the drug is converted to a form that is more readily eliminated
✔✔CYP450 metabolism - ✔✔A family of enzymes that metabolize drugs & each is
responsible for a single type of metabolic reaction. This is the most studied drug
metabolism reaction which is a mixed function oxidase reaction. It catalyzes the
metabolism of a large # of diverse drugs & chemicals that are highly lipid soluble.
✔✔CYP Inducers - ✔✔increase the amount/expression of CYP450 enzymes, causing
increased metabolism of drugs. Result is decreased pharmacologic action of the drug.
- reduce the plasma level therefore decreasing the effectiveness of the drug
example of inducers:
Benzopyrenes in cig. smoke
chronic ETOH
barbiturates (phenobarbital)
carbamazepine
rifampin
phenytoin
"Smoking and Drinking in Barbs Car Rifs her Phen"
so, a patient is taking birth control and is later prescribed rifampin for a bacterial
infection. What happens next?
✔✔CYP inhibitors - ✔✔decrease the amount/expression of CYP450 enzymes, leading
to reduced metabolism of drugs and increased pharmacologic action of the drug
-- increase the plasma level; increase the toxicity risk of the drug
,Examples
cimetidine
omeprazole
ketoconazole
erythromycin
grapefruit juice
protease inhibitors (ritonavir)
"COKE and Grapefruit juice with my PI"
depakote
isoniazid
fluconazole
ETOH
chloramphenicol
OR
"sickfaces.com"
Sodium valproate
Isoniazid
Cimetidine
Ketoconazole
Fluconazole
Alcohol..binge drinking
Chloramphenicol
Erythromycin
Sulfonamides
Ciprofloxacin
Omeprazole
Metronidazole
Grapefruit juice
So, a patient is taking warfarin as an anticoagulant and later prescribed cimetidine for
peptic ulcers. what happens next?
✔✔Examples of what could happens when two drugs that use the same pathway are
taken - ✔✔Estrogen(birth control) and tegretol(seizures)
Tegretol induces the CYP450 system=increased metabolism of estrogen=lowered blood
levels of estrogen which reduces contraceptive effect and increases risk of pregnancy.
Erythromycin inhibits the CYP450 which reduces metabolism of drugs, can lead to
increased & even toxic levels of other drugs.
✔✔What is CYP450 and what is the role of grapefruit juice? - ✔✔CYP450 is an enzyme
involved in metabolism. Grapefruit "knocks it out" for 3 days. If a drug needs CYP450 to
leave the body and there is no CYP450, the drug BUILDS up for 3 days. The drug
action will be higher.
, ✔✔Enzyme competition Enzyme inhibition - ✔✔Results in decreased metabolism and in
increased pharmacologic action of drug. The drug stays in the body longer.
✔✔Example of enzyme competition/inhibition - ✔✔Grapefruit juice
drug inhibits enzymes that normally break down certain drugs. Decreased breakdown
means that these drug will have increased time in the body, therefore prolonged action.
✔✔Practitioners use the following mnemonic to ensure that all areas of medication
history are covered.
AVOID Mistakes - ✔✔AVOID Mistakes
Allergies?
Vitamins & herbs?
Old drugs and OTC (as well as current)?
Interactions?
Dependence? Do you need a contract?
Mendel - family history of benefits or problems with any drugs?
✔✔Drugs to look out for toxic interactions with other drugs - ✔✔Drugs that induce or
inhibit the CYP450 enzymes
✔✔Enzyme Induction - ✔✔Increasing the metabolic pathway and results in less action
of drug- the drugs exits the body faster.
Some drugs enhance cytochrome P450 enzyme activity and cause increased amount of
P450 enzymes, hence, increased metabolism. Less amount of the drugs because it is
metabolized & higher amounts of the drug metabolite.
✔✔Prodrug - ✔✔pharmacologically inactive medications that are metabolized into an
active form within the body.
✔✔Example of a pro drug - ✔✔levodopa; methyldopa
Dopamine cannot pass blood-brain barrier so cannot be used to treat dopamine
shortage in Parkinson's but L-DOPA can pass BBB & once in cell it is converted into
dopamine.
✔✔Advantage of Pro drugs - ✔✔Relates to terms of their absorption and distribution.
✔✔Disadvantage of pro drugs - ✔✔Inhibition of some enzymes can leave the prodrug
unchanged in some cases cause toxicity.
Sometimes the metabolite is of a drug is more toxic & can remain in the body longer
than the drug & cause undesirable effects.
✔✔Poor metabolizers - ✔✔lack a working enzyme.
2 loss-of funciton alleles
AND ANSWERS SURE A+
✔✔Competitive antagonist - ✔✔Any pharmacologic antagonist that competes with the
binding of agonists at the binding site.
typical of drugs that bind reversibly to the receptor
inhibition can be overcome by increasing the concentration of the agonist to achieve the
same maximal effect
✔✔drugs that decrease renal clearance - ✔✔acetaminophen
anti-arrhythmics
anticonvulsants
anti-depressants
anti-psychotics
beta blockers
theophylline
warfarin
benzos
✔✔Non-competitive antagonist - ✔✔Any pharmacologic antagonist that binds to a site
on the receptor other than the agonist binding site. The Agonist will be able to bind but
not able to activate due to the presence of the antagonist
typical of drugs that bind irreversibly or allosterically to the receptor; this is a drug that
prevents the agonist at any concentration from producing a maximum effect on a given
receptor
✔✔Examples of chemical Antagonists - ✔✔Digibind for Digitalis
Protamine for Heparin
✔✔Chemical AnTagonist - ✔✔binds directly to the agonist, not the receptor, and
deactivates the agonist
"CAT attacks an agonist"
,✔✔Physiologic antagonist - ✔✔drug or chemical that has an opposite effect through
different physiologic pathways.
They work on separate receptors to cause opposite physiologic effects
ex. glucocorticoid hormone can increase BG
insulin would oppose the action
---act on distinct receptor-effector systems
✔✔Classic Example of a physiologic antagonist - ✔✔Epinephrine given to counter act
the effects of Histamine and prevent vascular collapse.
✔✔Metabolism (biotransformation) - ✔✔A process that changes one chemical into
another usually through the use or production of energy. In the case of drugs this
usually takes place in the endoplasmic reticulum of the cells in the liver via enzymatic
processes.
prepares for excretion
the drug is converted to a form that is more readily eliminated
✔✔CYP450 metabolism - ✔✔A family of enzymes that metabolize drugs & each is
responsible for a single type of metabolic reaction. This is the most studied drug
metabolism reaction which is a mixed function oxidase reaction. It catalyzes the
metabolism of a large # of diverse drugs & chemicals that are highly lipid soluble.
✔✔CYP Inducers - ✔✔increase the amount/expression of CYP450 enzymes, causing
increased metabolism of drugs. Result is decreased pharmacologic action of the drug.
- reduce the plasma level therefore decreasing the effectiveness of the drug
example of inducers:
Benzopyrenes in cig. smoke
chronic ETOH
barbiturates (phenobarbital)
carbamazepine
rifampin
phenytoin
"Smoking and Drinking in Barbs Car Rifs her Phen"
so, a patient is taking birth control and is later prescribed rifampin for a bacterial
infection. What happens next?
✔✔CYP inhibitors - ✔✔decrease the amount/expression of CYP450 enzymes, leading
to reduced metabolism of drugs and increased pharmacologic action of the drug
-- increase the plasma level; increase the toxicity risk of the drug
,Examples
cimetidine
omeprazole
ketoconazole
erythromycin
grapefruit juice
protease inhibitors (ritonavir)
"COKE and Grapefruit juice with my PI"
depakote
isoniazid
fluconazole
ETOH
chloramphenicol
OR
"sickfaces.com"
Sodium valproate
Isoniazid
Cimetidine
Ketoconazole
Fluconazole
Alcohol..binge drinking
Chloramphenicol
Erythromycin
Sulfonamides
Ciprofloxacin
Omeprazole
Metronidazole
Grapefruit juice
So, a patient is taking warfarin as an anticoagulant and later prescribed cimetidine for
peptic ulcers. what happens next?
✔✔Examples of what could happens when two drugs that use the same pathway are
taken - ✔✔Estrogen(birth control) and tegretol(seizures)
Tegretol induces the CYP450 system=increased metabolism of estrogen=lowered blood
levels of estrogen which reduces contraceptive effect and increases risk of pregnancy.
Erythromycin inhibits the CYP450 which reduces metabolism of drugs, can lead to
increased & even toxic levels of other drugs.
✔✔What is CYP450 and what is the role of grapefruit juice? - ✔✔CYP450 is an enzyme
involved in metabolism. Grapefruit "knocks it out" for 3 days. If a drug needs CYP450 to
leave the body and there is no CYP450, the drug BUILDS up for 3 days. The drug
action will be higher.
, ✔✔Enzyme competition Enzyme inhibition - ✔✔Results in decreased metabolism and in
increased pharmacologic action of drug. The drug stays in the body longer.
✔✔Example of enzyme competition/inhibition - ✔✔Grapefruit juice
drug inhibits enzymes that normally break down certain drugs. Decreased breakdown
means that these drug will have increased time in the body, therefore prolonged action.
✔✔Practitioners use the following mnemonic to ensure that all areas of medication
history are covered.
AVOID Mistakes - ✔✔AVOID Mistakes
Allergies?
Vitamins & herbs?
Old drugs and OTC (as well as current)?
Interactions?
Dependence? Do you need a contract?
Mendel - family history of benefits or problems with any drugs?
✔✔Drugs to look out for toxic interactions with other drugs - ✔✔Drugs that induce or
inhibit the CYP450 enzymes
✔✔Enzyme Induction - ✔✔Increasing the metabolic pathway and results in less action
of drug- the drugs exits the body faster.
Some drugs enhance cytochrome P450 enzyme activity and cause increased amount of
P450 enzymes, hence, increased metabolism. Less amount of the drugs because it is
metabolized & higher amounts of the drug metabolite.
✔✔Prodrug - ✔✔pharmacologically inactive medications that are metabolized into an
active form within the body.
✔✔Example of a pro drug - ✔✔levodopa; methyldopa
Dopamine cannot pass blood-brain barrier so cannot be used to treat dopamine
shortage in Parkinson's but L-DOPA can pass BBB & once in cell it is converted into
dopamine.
✔✔Advantage of Pro drugs - ✔✔Relates to terms of their absorption and distribution.
✔✔Disadvantage of pro drugs - ✔✔Inhibition of some enzymes can leave the prodrug
unchanged in some cases cause toxicity.
Sometimes the metabolite is of a drug is more toxic & can remain in the body longer
than the drug & cause undesirable effects.
✔✔Poor metabolizers - ✔✔lack a working enzyme.
2 loss-of funciton alleles
