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49 Cards in this Set
- Front
- Back
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Volume of distribution equation?
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(Amount of drug in body IV)/([Plasma] at time zero)
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Clearance equations (2)
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CL=(0.7 x Vd)/(t 1/2 )
CL = ([Ux] * flow rate)/([plasmax]) |
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Drugs with zero order elimination?
a PEA is shaped like a 0 |
Phenytoin
Ethanol Aspirin |
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Half life equation
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t1/2 = (0.7 * Vd)/ CL
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How long does it take to reach steady state [plasma] of a drug given at a constant rate IV? (give percentages)
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4-5 half lives.
1 = 50% 2 = 75% 3 = 87.5% 4 = 93.75% |
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Maintenance dose equation?
What factor of an individual patient affects the maintenance dose? |
MD = Css * CL; this equation assumes IV infusion meaning that bio-availability (F) is 100%.
If drug is oral then equation changes to: MD = (CL * [plasma x]/F Clearance affects the maintenance dose so with renal disease the maintenance dose is decreased |
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Loading dose equation
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assuming 100% bio-availability:
LD = Css * Vd or with a lesser bio-availability: LD = (Vd * [plasma x])/F |
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What is phase 1 metabolism?
What patient population looses this phase first? |
Redox reactions and hydrolysis rxn's. Done by Cytochrome P-450 in the Smooth ER of hepatocytes mainly.
The elderly loose phase 1 metabolism before phase 2 |
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Phase 2 metabolism?
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Conjugation takes place resulting in a very polar inactive metabolite that is normally renally excreted.
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Km is what?
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reflects the affinity of enzyme for its substrate.
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Competitive inhibitors do what to the following?
- Vmax - Km - Pharmacodynamics |
- no change to Vmax
- increase Km - decrease potency |
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Non-competitive inhibitors do what to the following?
- Vmax - Km - Pharmacodynamics |
- decrease Vmax
- unchanged Km - decrease efficacy |
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The higher the therapeutic index (TI) the what the drug?
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Safer
TI = (LD50)/(ED50) |
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Nicotinic ACh receptors are what type of channel?
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Na/K channel
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Muscarinic ACh receptors are what type of channel?
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G-protein coupled receptors
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Partial agonists always do what to Vmax?
Depending on the partial agonist it can either increase or decrease Km. what happens with each instance? |
lower it decreasing efficacy.
increase in Km = lower affinity = decreased potency (shift right) decreased Km = higher affinity = increased potency (shift left) |
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Cytochrome P-450 inhibitors?
PICK EGS what does CYP-450 inhibitor mean? |
P - protease inhibitors
I - isoniazid C - cimetidine K - ketoconazole E - Erythromycin G - Grape fruit juice S - sulfonamides If you inhibit something that breaks down a drug the drug will stick around longer than normal. |
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Gq down stream cascade? (Cutsie)
Gs, Gi ? |
Gq activates PLC---IP3 - Ca, or DAG -PKC
Gs Gi = both adenylyl cyclase PKA |
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Gprotein class and its receptor acronym
qiss qiq siq sqs |
q a1
i a2 s b1 s b2 q M1 i M2 q M3 s D1 i D2 q H1 s H2 q V1 s V2 |
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Vesamicol
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blocks ACh packaging into vesicles in presynaptic
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Hemicholinium ?
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blocks choline reuptake into presynaptic nerve for reuse
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Botulinum?
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blocks docking and release of ACh from presynaptic terminal
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Metyrosine?
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blocks tyrosine to DOPA
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Reserpine ?
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Blocks Dopamine packaging into vesicles in presynaptic terminal
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Amphetamine?
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stimulates docking of vesicle and release of NE into synapse
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Cocaine, TCA's, Amphetamine's
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Blocks reuptake of Ne into presynaptic terminal.
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How does NE modulate it's own release
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by binding alpha2 and M2 receptors on presynaptic nerve blocking vesicle docking and release.
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How does the SNS affect the following?
1. Heart 2. Eye 3. Salivary Glands 4. Bronchiolar Smooth muscle 5. Bladder 6. Male GU 7 GI tract |
1. Increase HR and contractility
2. mydriasis 3. viscous secretions 4. relaxes 5. prevents urination 6. Ejaculate 7. stop digestion |
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How does the PNS affect the following organs?
1. Heart 2. Eye 3. Salivary Gland 4. Bronchiolar Smooth muscle 5. Bladder 6. Male GU 7. GI tract |
1. decrease HR and contractility
2. Miosis 3. watery secretions 4. contracts 5. causes urination 6. Erection 7. increase digestion |
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Name 4 cholinomimetic agents (direct agonists)
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1. Bethanechol (post op use)
2. Carbachol (glaucoma, relief IOP) 3. Pilocarpine (stims sweat, tears, saliva) 4. Methacholine (challenge test for asthma) |
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Name 3 anticholinesterases used in Alzheimer's.
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Donepezil
Galantamine Rivastigmine these three all inhibit AChesterase |
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How do you treat Myasthenia Gravis
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AChesterase inhibitors
corticosteroids thymectomy plasma pharesis |
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What does pralidoxime do?
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regenerates AChesterases after organophosphate poisoning.
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Anti-muscarinics (anti-ACh) drugs include what?
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TROP in name:
Homatropine Tropicamide Atropine Ipratroprium benztropine Scopalamine etc... |
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What anticholinergics are used in tx of urge type urinary incontinence?
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Oxybutynin
tolterodine darifenacin and solifenacin trospium all these drugs block M receptors on detrusor muscle and inhibit spasmodic contractions decreasing urinary urgency. |
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What pt. pop is Atropine (musc antag) contraindicated?
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- Elderly
- infants with fever can cause hyperthermia - Glaucoma pt's - BPH or any cause of urinary retention - Pt's with decreased GI motility |
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which drug helps improve FEV1 in a pt with COPD?
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Ipratropium
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A schizo with urinary retention due to his neuroleptic. How do you tx?
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Bethanechol
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Clinical trials:
Phase 1? Phase 2? Phase 3? Phase 4? |
1 = is it safe
2 = does it work (efficacy) 3 = Does it work better 4 = Post market surveillance |
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What is Hexamethonium?
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It's a ganglionic nicotinic antagonist used experimentally. prevents vagal reflex responses to changes in BP (prevents reflex bradycardia caused by NE)
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How does Hexamethonium affect the following?
1. BP 2. HR 3. COP 4. Urine output 5. GI motility 6. Pupil of the eye |
1. decrease (sns antagonist)
2. increase (vagal nerve blocked) 3. decrease 4. decrease 5. decrease 6. mydriasis |
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Explain Hexamethoniums different looking effects throughout the body.
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SNS is dominant in BV's so Hex will look like a SNS antagonist with BP. PNS is dominant in most other tissues to Hex will look like a PNS antagonist in those those tissues.
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Given as nebulizer for asthma?
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albuterol.
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Whats the drug of choice for a pt. with CHF and asthma?
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Levalbuterol because it has NO beta 1 effect
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DOC for anaphylaxis
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EPI
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DOC for cardiogenic shock
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Dobutamine
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DOC for septic shock
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Norepi
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Given SubQ for asthma
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terbutaline a beta agonist
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What drug is most appropriate in a pt in shock because they maintains renal blood flow?
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Dopamine (D2,D1 agonists)
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