Pharmacology Flashcards
Km
inversely related to the affinity of the enzyme for its substrate
Vmax
directly proportional to the enzyme concentration
Line-weaver burk plot
X intercept = 1/-Km
Y intercept = 1/Vmax
slope = Km/Vmax
Volume of distribution
Vd = amount of drug in body/ plasma concentration
- Vd low if drug is in the blood only, med if in the interstitial space, and high if in all tissues including fat
half life
- drugs infused at a constant rate take 4-5 HL to reach steady state
- takes 3.3 HL to reach 90% steady state levels
zero vs. first order elimination
- zero = constant amount cleared per unit time
- PEA - phenytoin, ethanol, aspirin
- first = constant fraction cleared per unit time
weak acid drugs and urine pH
- phenobarb, methotrexate, aspirin
- trapped in basic environment, treat overdose with bicarb
weak base drugs and urine pH
- amphetamines
- trapped in acidic environment, treat overdose with ammonium chloride
therapeutic index
TD50/ED50
median toxic dose/median effective dose
parasympathetic innervation of cardiac smooth muscle, gland cells and nerve terminals
- Ach at nicotinic receptor at ganglion
- Ach at muscarnic receptor at tissue
sympathetic innervation of sweat glands
- Ach at nicotinic receptor at ganglion
- Ach at muscarinic receptor at tissue
sympathetic innervation of cardiac smooth muscle, gland cells and nerve terminals
- Ach at nicotinic receptor at ganglion
- NE at alpha/beta receptor at tissue
sympathetic innervation of renal vasculature and smooth muscle
- Ach at N receptor at ganglion
- Dopamine at D1 receptor at tissue
sympathetic innervation of adrenal medulla
- Ach at N receptors stimulates it to release Epi and NE
somatic innervation of skeletal muscle
- Ach directly at N receptors at tissue
alpha1 receptor
- Gq receptor
- inc vascular smooth muscle contraction, inc pupillary dilator contraction, inc intestinal and bladder sphincter muscle contraction
a2 receptor
- Gi receptor
- decreases sympathetic outflow, dec insulin release, dec lipolysis, inc platelet aggregation
b1 receptor
- Gs receptor
- inc HR, contractilty, renin release, lipolysis
b2 receptor
- Gs receptor
- vasodilation, bronchodilation, inc HR, contractility, lipolysis, insulin release
- decreased uterine tone, ciliary muscle releaxation, inc aqueous humor production
M1 receptor
- Gq receptor
- CNS, enteric nervous system
M2 receptor
- Gi receptor
- decreased HR and contractility of atria
M3 receptor
- Gq receptor
- inc exocrine gland secretions, inc gut peristalsis, inc bladder contraction, bronchoconstriction, inc pupillary sphincter muscle contraction, ciliary muscle contraction
D1 receptor
- Gs receptor
- relaxes renal vascular smooth muscle
D2 receptor
- Gi receptor
- modulates transmitter release, esp in brain
H1 receptor
- Gq receptor
- inc nasal and bronchial mucus production, inc vascular permeability, contraction of bronchioles, pruritis and pain
H2 receptor
- Gs receptor
- inc gastric acid secretion
V1 receptor
- Gq receptor
- inc vascular smooth muscle contraction
V2 receptor
- Gs receptor
- inc H20 permability and resorption in the collecting tubules of the kidney
- V2 is found in the 2 kidneys
which receptors are paired with which G proteins
HAVE 1 M and M --- Gq - H2, a1, V1, M1 and M3 MAD 2s ----- Gi - M2, a2, D2 all the rest work on Gs
bethanecol
- cholinomimetic drug used for post op ileus, neurogenic ileus and urinary retention
- activates Bowel and Bladder smooth muscle, resistant to AchE
- “bethany call me maybe if you want to move your bowel or bladder”
carbachol
- cholinomimetic agent used for glaucoma, pupillary constriction, and relief of intraocular pressure
- “CARBon copy of AcetylCHOLine”
pilocarpine
potent stimulator of sweat, tears and saliva
- used for open and closed angle glaucoma
- “you cry, drool and sweat on your PILOw”
neostigmine
- postop and neurogenic ileus and urinary retention, myasthenia gravis, reversal of NMJ blockade
- inc endogenous Ach
- Neo = No CNS penetration
pyridostigmine
-myasthenia gravis (long acting), does not penetrate the CNS