Basic Pharmacology Deck 1 Flashcards
What drugs are ideal for sublingual administration?
lipid-soluble drugs that would be metabolized in the gut or liver (no first pass liver metabolism). Used for nitrates and certain hormones.
What is the general order of bioavailability of oral drugs in the following forms (listed here alphabetically): capsule coated tablet solution suspension tablet
solution > suspension > capsule > tablet > coated tablet
What organs make up the ‘central compartment?’
heart, blood liver, brain and kidney. Drugs equilibrate rapidly.
What organs make up the ‘peripheral compartment?’
adipose, skeletal muscle, other organs which are less well-perfused. Drugs equilibrate more slowly.
What are xenobiotics?
Foreign compounds to which the body is exposed.
In xenobiotic metabolism, what is the difference between Phase I and Phase II reactions?
Phase I: convert a drug to a more polar compound by introducing or unmasking polar functional groups, such as -OH, -NH2, -SH.
Phase II: Conjugation to newly established polar group with endogenous compounds such as: glucuronic acid, sulfuric acid, acetic acid or glycine.
Name two inducers of P450 enzymes
phenobarbital; polycyclic aromatic hydrocarbons (such as those found in cigarette smoke or charcoal broiled foods).
Name three inhibitors of P450 enzymes
erythromycin; ketonazole; cimetidine
How can one prolong the duration of effect of penicillins?
Give probenecid, which competitively inhibits tubular secretion in the kidney.
What substance increases percutaneous absorption of many drugs?
dimethyl sulfoxide (DMSO).
What are the mechanisms by which ACh acts as either an excitatory or inhibitory transmitter in:
1) skeletal muscle
2) smooth muscle
3) cardiac muscle
1) skeletal - excitatory, increases Na+ and K+ conductance.
2) smooth - excitatory, increases Na+ conductance.
3) cardiac muscle - inhibitory, slows heart beat by increasing K+ conductance.
Where is butyrocholinesterase found?
In blood and liver
What action does the parasympathetic system have on the following organs?
1) eye
2) heart
3) GI
4) bladder
5) sweat, lacrimal glands.
1) constricts pupil (miosis)
2) decreases heart rate
3) increases motility and tone
4) contraction
5) increases secretion.
What transmitter / receptor are found on parasympathetic postganglionic cells?
cholinergic muscarinic receptors.
What is the catecholamine synthesis pathway?
Tyrosine -> dopa -> dopamine -> norepinephrine -> epinephrine
What is the rate-limiting step in catecholamine synthesis?
Tyrosine -> DOPA (via tyrosine hydroxylase). enzyme is unique to catecholaminergic neurons and chromatin cells.
What converts Dopamine to norepi, where does the conversion occur, and why does it matter?
Dopamine beta-hydroxylase; conversion occurs in storage vesicle, DBH is non-specific, will oxidize tyramine to octopamine.
Where is most norepi located?
90-95% in storage vesicles; pumped in by VMAT-2 (vesicular monoamine transporter)
What happens to norepi after being released into the synaptic terminal?
It is taken back up by norepi transporter (NET) - NET also transports DA and E.
What substances inhibit NET?
cocaine; imipramine (tricyclic antidepressant).
What metabolizes most NE and E released by the adrenal medulla?
catechol-O-methyltransferase (COMT) in the liver.
What is the structure of adrenergic receptors and what are the effector molecules for:
1) alpha1 receptors
2) alpha2 receptors
3) beta receptors
All are GPCRs.
1) IP3/DAG pathway, calcium release.
2) Ginhibitory, causes PKA to go down.
3) Gstimulatory, causes PKA to go up.
Where are alpha1 receptors found and what does their stimulation cause?
1) vascular smooth muscle -> contraction.
2) intestinal smooth muscle -> relaxation
Where are alpha2 receptors found and what does their stimulation cause?
1) presynaptic nerve terminals -> decrease of NE release.
