Pharm Flashcards
Km
=[S] at 1/2 Vmax; inverse to affinity for substrate
Vmax
Directly proportional to enzyme concentration (V of saturation)
Competitive inhibitor
Same Vmax, lower Km (takes longer to reach vmax); reversible
Noncompetitive inhibitor
Higher Km, lower Vmax
Cooperative kinetics
Sigmoid curve (like hemoglobin)
Most enzymes have a ____ curve
Hyperbolic
On a lineweaver burk plot
High y intercept = lower V max (1/V on Y axis); further right x intercept (closer to zero) –> higher Km, lower affinity
Reversible competitive inhibitors -- Resemble substrate Overcome by increased [S] Bind active site Effect on Vmax Effect on Km Pharmacodynamics
Resemble substrate: yes Overcome by increased [S]: yes Bind active site: yes Effect on Vmax: no change Effect on Km: increased Pharmacodynamics: decreased potency
Irreversible competitive inhibitors -- Resemble substrate Overcome by increased [S] Bind active site Effect on Vmax Effect on Km Pharmacodynamics
Resemble substrate: yes Overcome by increased [S]: no Bind active site: yes Effect on Vmax: decreased Effect on Km: no change Pharmacodynamics: decreased efficacy
Noncompetitive inhibitors -- Resemble substrate Overcome by increased [S] Bind active site Effect on Vmax Effect on Km Pharmacodynamics
Resemble substrate: yes Overcome by increased [S]: no Bind active site: yes Effect on Vmax: decreased Effect on Km: no change Pharmacodynamics: decreased efficacy Compared to uncompetitive -- binds equally well no matter whether substrate is bound
Uncompetitive inhibitor
Only binds to an enzyme bound to substrate
Decreases Vmax, decreases Km (increased sticking in enzyme); parallel on LB plot
Vd=
Amount drug in body/plasma drug conc
Low Vd compartment and type
Intravascular large/charged molecules often bound to plasma proteins
Medium Vd compartment and type
ECF small hydrophilic molecules
High Vd compartment and type
All tissues including fat, small lipophilic molecules, esp if bound to tissue protein
CL=
rate of elimination/plasma drug conc. (volume of plasma cleared of drug per unit of time)
aka Vd*Ke (elimination const)
How many half lives to reach steady state in 1st order kinetics?
4-5
How many half lives to reach 90% of steady state in first order kinetics?
3.3
T1/2 in first order kin=
(0.693*Vd)/CL
Loading dose=
(Cp*Vd)/F
Where Cp is conc. at steady state
F is bioavailability
Maintenance dose=
(CpCLt)/F
Where Cp is conc at steady state
F is bioavailability
t is dosage interval
In renal and liver disease, how do maintenance doses change?
Maintenance goes down
In renal and liver disease, how do loading doses change?
Loading dose doesn’t change (trick q)
Additive drug effect
Effect of A+B=sum of individual effects
Permissive drug effect
Need A for proper fxn of B
Synergistic drug effect
A+B together > sum of their effects individually
Tachyphlactic drug interaction
Acute decrease in reponse to drug after initial/repeated admin
Zero order elim
Rate of elim constant regardless of Cp; eg Phenytoin, ethanol, aspirin at high conc. (constant AMOUNT)
First order elim
Rate of elim directly proportional to drug conc. (constant FRACTION), Cp decreases exponentially w/ time; e.g. most drugs
Weak acids and how to get rid of them in overdose
Ex: phenobarb, methotrexate, aspirin
Trapped in basic environments – give sodium bicarb to alk the urine
Weak bases and how to get rid of them in overdowse
Ex: amphetimines, TCAs
Trapped in acidic environments – give ammonium Cl to acidify urine
Phase I metabolism
Reduction, oxidation, hydrolysis w P50 –> slightly polar, water soluble metabolites (often still active)
First type of metabolism lost w/ age
Phase I
Phase II metabolism
Conjugation (Methylation, glucuronidation, acetylation, sulfation) –> very polar inactive metabolites that can be renally excreted
Slow acetylators have increased side effects from some drugs due to slower metabolism
Efficacy
Maximal effect a drug can produce (Vmax)
Partial agonist efficacy vs full agonist efficacy
Partial
Potency
Amount of drug needed for a given effect (EC50 – i.e. 50% of maximal effect)
Left shift in potency=
Lower EC50, higher potency, less drug needed for an effect
Competitive antagonist
Right shift in curve –i.e. lower potency, but same efficacy and can be overcome by increased substrate conc
Noncompetitive antagonist
Shifts curve down (lower efficacy) – not able to be overcome by a higher [S]
Partial agonists
Same site as a full agonist, decreases efficacy, potency independent
Therapeutic index
Measurement of drug safety
TD50/ED50 (toxic median dose/effective median dose)
Therapeutic window
Dosage range to safely/effectively treat disease
Lower TI drugs
Require monitoring; eg Warfarin, theophylline, dig, Li,
“Warning These Drugs are Lethal!”
All first synapses are
Ach on Nicotinic receptors
PNS has long/short pre synaptic
Long
SNS has long/short pre synaptic
Short
Exception to SNS rules
Sweat glands – Ach on M like PNS
alpha1
Gq
Vascular smooth muscle contraction, pupillary dilator contracts (mydriasis); intestinal/bladder sphincter contraction
alpha2
Gi
Less sympathetic outflow, less insulin release, less lipolysis, increased platelet agg, less aqueous humor made
beta1
Gs
Increased heart rate, increased contractility, renin released, increased lipolysis
beta2
Gs
Vasodilation, bronchodilation, increased lipolysis, increased insulin release, less uterine tone (tocolysis), ciliary muscle relaxation, more aqueous humor
beta3
Gs
Increased lipolysis, thermogenesis in skeletal m, bladder relaxation
M1
Gq
Higher cognitive fxns, stimulates enteric nervous system
M2
Gi
Lower heart rate, less atrial contractility
M3
Gq
Increases exocrine gland secretions (lacrimal, sweat, salivary, gastric acid), causes gut peristalsis, bladder contraction, bronchoconstriction, pupillary muscle contraction (miosis), ciliary muscle contraction (accomodation), increases release of insulin
D1
Gs
Relaxes renal vascular smooth muscle, activates direct pathway of striatum
D2
Gi
Modulates transmitter release (esp in brain), inhibition of indirect pathway of striatum
(GI, Inhibition Indirect path)
H1
Gq
Nasal and bronchial muscus production, vascular permeability, contraction of bronchioles, pruritus, pain
H2
Gs
Gastric acid secretion
V1
Gq
Vascular smooth muscle contraction
V2
Gs
H2O permeability and reabsorption in collecting tubules of kidney
Gq receptor examples and effector enzyme
H1, alpha1, V1, M1, M3
“HAVe 1 M&M”
Works via PLC (Ca/PKC)
Gs receptor examples and effector enzyme
B1, B2, B3, D1, H2, V2
Works via AC upregulation
Gi receptor examples and effector enzyme
M2, alpha2, D2
Works via AC downregulation
NE self regulation
Via alpha2 autoreceptors
Selective beta blockers (6)
B1 – acebutolol (partial agonist), atenolol, betaxolol, bisoprolol, esmolol, metoprolol
Non selective beta blockers (4)
Nadolol, pindolol (partial agonist), propanolol, timolol
Nonselective beta/alpha blockers
Labetolol, carvedilol
Special beta blockers
Nebivolol – cardiac selective B1, stim of B3 in vasculature –> NO synthase –> reduces SVR
B blockers that reduce mortality in HF
Bisoprolol, carvedilol, metoprolol
B blocker partial agonists
Pindolol, acebutalol (don’t use in heart failure)
Tetrodotoxin – source, action, symptoms, tx
Pufferfish – highly potent, binds voltage gated Na channels in heart/nerve –> prevents depolarization –> leads to nausea, diarrhea, paresthesias, weakness, dizziness, lost of reflexes (tx supportive)
Ciguatoxin – source, action, symptoms, tx
Reef fish (barracuda, snapper, moray eel) –> opens Na channels –> depolarization –> NVD, perioral numbness, reversal of hot/cold sensations, bradycardia, heart block, hypotension (tx supportive)
Histaime (scombroid poisoning) – source, action, symptoms, tx
From spoiled dark-meat fish like tuna, mahimahi, mackerel, bonito –> bacterial histidine decarboxylase causes histadine –> histamine –> mimics anaphylaxis (tx: antihistamines, albuterol and epi if needed)
Beers drugs
- Anticholinergics, antihistamines, antidepressants, benzos, opioids (increase risk of delirium, sedation, falls, constipation, urinary retention)
- Alpha blockers (increases risk of hypotension)
- PPs (increase c diff risk)
- NSAIDs (increased risk of GI bleeds, esp w anticoags)
Acetaminophen overdose tx
N-acetylcystein (replenishes glutathione)
AChE inhibitors, organophosphates overdose tx
Atropine > pralidoxime (muscle)
Antimuscarinic, anticholinergic agents overdose tx
Physostigmine, control hyperthermia
Arsenic overdose tx
Dimercaprol, succimer
Benzos overdose tx
Flumazenil
B blockers overdose tx
Glucagon, atropine
CO overdose tx
100%/hyperbaric O2
Cu overdose tx
Penicillamine, trientine
Cyanide overdose tx
Nitrate + thiosulfate, hydroxocobalamin
Dig overdose tx
Anti-dig Fab fragments
Heparin overdose tx
Protamine sulfate
Fe overdose tx
Deferoxamine, deferasirox, deferiprone
Pb overdose tx
EDTA, dimercaprol, succimer, penicillamine
Mercury overdose tx
Dimercaprol, succimer
Methanol, ethylene glycol (antifreeze) overdose tx
Fomepizole>ethanol, dialysis
Methemoglobin overdose tx
Methylene blue, vit C
Opioids overdose tx
Naloxone
Salicylates overdose tx
NaHCO3 (alkalinize urine), dialysis
TCAs overdose tx
NaHCO3 (alkalinize urine)
Warfarin overdose tx
VIt K (delayed effect), FFP (immediate)
Drugs causing coronary vasospasm
Amphetamines, cocaine, ergot alkaloids, sumatriptan
Drugs causing cutaneous flushing
Vanco, Adenosine, Niacin, Nitrates, Ca2+ channel blockers, Echinocandins
VANNCE
Drugs causing dilated cardiomyopathy
Anthracyclines (doxorubicin, daunorubicin), prevent w/ dexrazoxane
Drugs causing torsades
AntiArrhythmics (Class Ia, III), antiBiotics (macrolides), anti”C”ycotics (haloperidol), antiDepressants (TCAs), antiEmetics (ondansetron)
ABCDE
Drugs causing adrenocortical insufficiency
HPA suppression 2o to glucocorticoid w/drawal
Drugs causing diabetes insipidis
Li, demeclocycline
Drugs causing hot flashes
Tamoxifen, clomiphene
Drugs causing hyperglycemia
Tacrolimus, Protease inhibs, Niacin, HCTZ, Corticosteroids
Taking Pills Necessitates Having Blood Checked
Drugs causing hypothyroidism
Li, amiodarone, sulfonamides
Drugs causing SIADH
Carbamazepine, Cyclophosphamide, SSRIs
Can’t Concentrate Serum Sodium
Drugs causing acute cholestatic hepatitis/jaundice
Erythromycin
Drugs causing diarrhea
Acamprosate, acarbose, cholinesterase inhibs, colchicine, erythromycin, ezetimibe, metformin, misoprostol, orlistat, pramlintide, quinidine, SSRIs
Drugs causing focal-massive hepatic necrosis
Halothane, Amanita phalloides, Valproic acid, ACetaminophen
Liver HAVAC
Drugs causing hepatitis
Rifamipin, isoniazid, pyrazinamide, statins, fibrates
Drugs causing pancreatitis
Didanosine, Corticosteroids, Alcohol, Valproic acid, Azathioprine, Diuretics (furosemide, HCTZ)
Drugs Causing A Violent Abdominal Distress
Drugs causing pill-induced esophagitis
Bisphosphonates, ferrous sulfates, NSAIDs, KCl, tetracyclines
(Minimize w/ upright posture and water intake)
Drugs causing pseudomembranous colitis
Ampicillin, cephalosporins, clindamycin, fluoroquinolones
Drugs causing agranulocytosis
Clozpine, Carbamazepine, PTU, Methimazole, Colchicine, Ganciclovir
Can Cause Pretty Major Collapse of Granulocytes
Drugs causing aplastic anemia
Carbemazepine, Methimazole, NSAIDs, Benzene, Chloramphenicol, PTU
Can’t Make New Blood Cells Properly
Drugs causing direct Coombs positive hemolytic anemia
Methyldopa, penicillin
Drugs causing DRESS
Allopurinol, anticonvulsants, abx, sulfa drugs
Potentially fatal and delayed, 2-8 wk latency –> fever, morbilliform rash, multiorgan involvement – tx w/ w/drawal and coricosteroids
Drugs causing gray baby syndrome
Chloramphenicol
Drugs causing hemolysis in G6PD def
Isoniazid, Sulfonamides, Dapsone, Primaquine, Aspirin, Ibuprofen, Nitrofurantoin
Hemolysis IS D PAIN
Drugs causing megaloblastic anemia
HydroxYUREa, Phenytoin, Methotrexate, Sulfa drugs
YURE having a MEGABLAST with PMS
Drugs causing thrombocytopenia
Heparin
Drugs causing thrombotic complications
Combined OC, hormone replacement therapy, SERMs (tamoxifen, raloxifene, clomiphene) – estrogen mediated
Drugs causing fat redistribution
Protease inhibitors, Glucocorticoids
Fat PiG
Drugs causing gingival hyperplasia
Phenytoin, Ca channel blockers, cyclosporine
Drugs causing hyperuricemia
Pyrazinamide, Thiazides, Furosemides, Niacin, Cyclosporine
Painful Tophi Feed Need Care
Drugs causing myopathy
Statins, fibrates, niacin, colchicine, daptomycin, hydrozychloroquine, IFN alpha, penicillamine, glucocorticoids
Drugs causing osteoporosis
Corticosteroids, depot medrozyprogesterone acetate, GnRH agonists, aromatase inhibitors, anticonvulsants, heparin
Drugs causing photosensitivity
Sulfonamides, Amiodarone, Tetracyclines, 5 Fu
SAT For Photo
Drugs causing rash (SJS)
Antiepileptics (esp lamotrigine), allopurinol, sulfa drugs, penicillin
Steven Johnson has epileptic allergy to sulf drugs and penicillin
Drugs causing SLE like syndrome
Sulfa drugs, Hydralazine, Isoniazid, Procainamide, Phenytoin, Etanercept
Having lupus is SHIPP-E
Drugs causing teeth discoloration
Tetracyclines (teethracyclines)
Drugs causing tendonitis, tendon rupture, and/or cartilage damage
Fluoroquinolones
Drugs causing cinchonism
Quinidine, quinine (tinnitus, hearing/vision loss, psychosis, cognitive impairment)
Drugs causing parkinson-like syndrome
Antipsychotics, Reserpine, Metoclopramide
Cogwheel rigidity of ARM
Drugs causing seizures
Isoniazid (in B6 def), Bupropion, Imipenem/cilastin, Tramadol, Enflurane
with seizures I BITE my tongue
Drugs causing tardive dyskinesia
Antipsychotics, metoclopramide
Drugs causing Fanconi syndrome
Cisplatin, ifosfamide, expired tetracyclines, tenofovir
Drugs causing hemorrhagic cystitis
Cyclophosphamide, isofosfamide (prevent by coadmin of mesna)
Drugs causing interstitial nephritis
Penicillins, furosemides, NSAIDs, PPIs, sulfa drugs
Drugs causing dry cough
ACE inhibs
Drugs causing pulmonary fibrosis
Methotrexate, Nitrofurantoin, Carmustine, Bleomycin, Busulfan, Amiodaron
My Nose Cannot Breate Bad Air
Drugs causing antimuscarinic side effects
Atropine, TCAs, H1 blockers, antipsychotics
Drugs causing disulfiram like reaction
1st gen Sulfanureas, Procarbazine, some Cephalosporins, Griseofulvin, Metronidazole
Sorry Pals Can’t Go Mingle
Drugs causing nephro/ototoxicity
Aminoglycosides, vanco, loop diuretics, cisplatin, amphotericin B (cisplatin tox may respond to amifostine)
P450 inducers (8)
Chronic alcohol use St johns wort Phenytoin Phenobarbitol Nevirapine Rifampin Griseofulvin Carbamazepine
Chronic alcoholics STeal PHEN PHEN and Never Refurse GReasy CARBs
P450 substrates
Antiepileptics
Theophylline
Warfarin
OCPs
Always Think When Outdoors
P450 Inhibitors (12)
Sodium valproate Isoniazid Cimetidine Ketoconazole Fluconazole Acute EtOH abuse Chloramphenicol Erythromycin (macrolides) Sulfonamides Ciprofloxacin Omeprazole Metronidazole
SICKFACES.COM
Sulfa drugs (8)
Sulfonamide abx, Sulfasalazine, Probenecid, Furosemides, Acetazolamide, Celecoxib, Thiazides, Sulfonylureas
Scary Sulfa Pharm FACTS
-azoles
Ergosterol synthesis inhibitor
-bendazole
Antiparasitic/antihelminthic
-cillin
TTPase (PBP)
-cycline
Protein synth inhibitor
-ivir
Neuraminidase inhibitor
-navir
Protease inhibitor
-ovir
DNA polymerase inhibitor
-thromycin
Macrolide abx
-ane
Inhalational general anesthetic
-azine
Typical antipsychotic
-barbital
Barbiturate
-caine
Local anesthetic
-etine
SSRI
-imipramine
TCA
-triptyline
TCA
-triptan
5HT1B/1D agonist
-zepam
Benzo
-zolam
Benzo
-chol
Cholinergic agonist
-curium
Nondepolarizing paralytic
-curonium
Nondepolarizing paralytic
-olol
B blocker
-stigmine
AchE inhib
-terol
B2 agonist
-zosin
A1 antagonist
-afil
PDE5 inhib
-dipine
DHP Ca channel blocker
-pril
ACE inhib
-sartan
AngIIRB
-statin
HMG-CoA reductase inhib
-xaban
Direct factor Xa inhib
-dronate
Biphosphonate
-glitazone
PPAR-gamma activator
-prazole
PPI
-prost
Prostaglandin analog
-tidine
H2 antagonist
-tinib
TK inhib
-tropin
Pituitary hormone
-ximab
Chimeric MAb
-zumab
Humanized MAb