DR.LEAL- DRUGS WITH IMPORTANT ACTIONS ON SMOOTH MUSCLES PART 2 Flashcards
also known as autacoids.
VASOACTIVE PEPTIDES
Angiotensin II, endothelins, and neuropeptide Y
ARE VASOCONSCTRICTOR OR DILATOR?
VASOCONSTRICTORS
Bradykinin, BNP (Brain Natriuretic Peptide), ANP
(Atrial Natriuretic Peptide), CGRP (Calcitonin Gene-Related Peptide that causes migraine, and the VIP VIP (vasoactive Intestinal Peptide)
VASOCONSTRICTORS OR VASODILATORS?
VASODILATORS
The end point of RAAS is to __________________ to maintain homeostasis.
increase blood pressure
potent vasoconstrictor via an enzyme called angiotensin-converting enzyme.
angiotensin II
produced in the lungs, but a little amount of it can also be produced by the kidneys.
Angiotensin-converting enzyme
conversion takes place in the lungs because angiotensin-converting enzyme is predominantly produced in the lungs.
Angiotensin I
antihypertensive drug especially used for pregnant patients that are eclamptic,
hydralazine
VD
hair grower with antihypertensive effect, nitroprusside
MINOXIDIL
Production of angiotensinogen is increased by:
○ Corticosteroids, estrogens, thyroid
hormones, and angiotensin II
○ Elevated during pregnancy
- That’s why pregnant patients can develop gestational hypertension.
○ Oral contraceptives (Pills) can increase blood pressure.
● Potent pressor agent (increase in blood pressure)
● Direct contraction of vascular especially arteriolar
smooth muscle
AngiotensinII
● Increases the release of epinephrine and
norepinephrine
● Direct positive inotropic (increases heart rate) action
on the heart
ANGIOTENSIN 2
Common side effect of this drug classification is cough.
ACE INHIBITORS
● Block angiotensin receptors
● Slow the progression of diabetic nephropathy
Angiotensin Receptor Blockers (ARBs)
LOSARTAN OR VALSARTAN
● Blocks the renal beta receptors involved in the sympathetic control of renin release
● E.g. Propranolol
Beta-adrenoceptor Blocking Drugs
● Dose-dependent reductions in plasma renin activity and plasma angiotensin I, angiotensin II, and aldosterone concentrations
● Contraindicated in pregnancy
ALISKIREN
which is a vasodilator: produce the four
classic symptoms of inflammation:
○ Redness
○ Local heat
○ Swelling
BRADYKININ
● Control of blood pressure through its action on the kidney: increase water reabsorption
● Regulation of arterial pressure by its vasoconstrictor action
Arginine Vasopressin (AVP)
Antidiuretic Hormone (ADH)
Beneficial in the treatment of septic and other vasodilatory shock states (V1a agonist activity)
AVP + Norepinephrine
● Release ANP from cardiac cells for homeostasis
● Synthesized primarily in cardiac atrial cells, but it is also synthesized in the ventricular myocardium, neurons in the CNS, PNS and in the lungs.
Atrial Natriuretic Peptide (ANP)
● Synthesized primarily in the heart
● Volume related
○ If there is an increase in volume, ____ is released to increase the pressure.
Brain Natriuretic Peptide (BNP)
Treatment of Congestive Heart Failure
Vasodilation and natriuresis
● Widely distributed in the CNS and PNS
● Major peptide neurotransmitters
● Marked vasodilation in most vascular beds
Vasoactive Intestinal Peptide
Most potent vasodilator
Calcitonin Gene-Related Peptide
——-Calcitonin, Adrenomedullin, Amylin
● Readily available
● Expressed constitutively in most cells
● Generates prostanoids for “housekeeping” functions,
such as gastric epithelial cytoprotection
PGH synthase-1 (COX-1)
● Readily inducible, its expression levels being dependent on the stimulus
● Major source of prostanoids
● Present when there is inflammation
PGH synthase-2 (COX-2)
Exert their therapeutic effects through inhibition of the COXs
NSAIDS
Indomethacin, Sulindac, Meclofenamate,
and Ibuprofen
Non-selective COX inhibitors:
Celecoxib = Diclofenac = Meloxicam = Etodolac < Valdecoxib «_space;Rofecoxib < Lumiracoxib = Etoricoxib
(increasing COX-2 selectivity)
Selective COX-2 inhibitors:
cyclooxygenase pathway inhibitor but irreversible
acetylates and inhibits both enzymes covalently and hence irreversibly
ASPIRIN
○ Abortifacient drug
○ A PGE1 derivative cytoprotective
prostaglandin used in preventing peptic ulcer (main use) and in combination with Mifepristone (RU-486) for terminating early pregnancies
MISOPROSTOL (CYTOTEC)
○ Inserted intravaginally to open the cervix and deliver the baby
○ Used in obstetrics to induce labor
Dinoprostone (PGE2) and PGF2α
○ Topically active PGF2α derivatives used in
ophthalmology to reduce intraocular pressure in open-angle glaucoma or ocular hypertension
LATANOPROST
Synthesized mainly by the vascular endothelium and is a powerful vasodilator and inhibitor of platelet aggregation
PROSTACYCLIN
pulmonary hypertension
Epoprostenol, Iloprost, Treprostinil
Block all the known pathways of eicosanoid synthesis
Corticosteroids
○ Block both prostaglandin and thromboxane formation by reversibly inhibiting COX activity
NSAIDs