12 Vasodilator Pharmacology Flashcards
What are indirect vasodilators?
drugs which block vasoconstriction
What are the 2 targets for indirect vasodilators?
ANS
RAAS
How can we target the ANS for indirect vasodilation?
sympathetic blockade
alpha 1 receptor blockers
How can we target the RAAS for indirect vasodilation?
angiotensin II is a vasoconstrictor
How does cGMP affect smooth muscle function?
affects Ca2+ channel opening duration
hence affects myosin : actin interaction
Name 6 potential uses of direct vasodilators
Hypertension Angina Pectoris Peripheral Vascular Disease Impotence Hair loss Cerebral function
What are the 3 types of treatment for angina pectoris?
1 - not vasodilators
2 - organic nitrates
3 - Ca2+ channel blockers
Name 2 drugs used to treat angina pectoris which aren’t vasodilators
beta blockers
ivabradine
Name the most common form of organic nitrate
Glyceryl Trinitrate (GTN)
What is the MOA of GTN?
broken into NO NO activates guanylate cyclase increases cGMP decreases venous return dcreases cardiac work decreases oxygen demand
What are the unwanted effects of GTN?
XS vasodilation…
hypotension (syncope and reflec tachycardia)
headache
constipation
Why is GTN not administered orally?
it is wiped out by 1st pass metabolism baby
What are the 2 main methods for GTN administration?
Sublingual
Tansdermal for phrophylaxis
What are the benefits of sublingual GTN?
easy, everyone knows where their mouth is
people can take it on a need-to basis
What are the therapeutic issues associated with GTN?
Physiological tolerance
Pharmacological tolerance
What is physiological tolerance?
other factors / mechanisms counteract the pharmacologcial effect
What is pharmacological tolerance?
fundamental change in MOA
What is the main group of calcium channel blockers used to treat angina called?
Dihydropyridines (DHPs)
What is the most common form of DHP?
Amlodipine
What tissue type do DHPs focus on?
vasculature
What is the overwhelming action of DHPs?
systemic vasodilation affecting afterload
What unwanted effects are associated with DHPs?
flushing
decreased GIT activity
What are the features of Raynaud’s Syndrome?
vascular spasm induced by cold weather
very painful
Which drug to we have to be cautious around when treating Raynauds Synrome?
Nifedipine (DHP), as it doesn’t always work
How is erection usually controlled?
NO -> cGMP
What is the MOA of Sildenafil?
PDE - type 5 inhibitor
this is specific to genital tissues
What interaction is important for sildenafil?
can itneract with other nitrate and be fatal
important to consider with vascular diseases!
What vasodilator is used to treat hair loss?
Minoxidil (Regaine)
What is the MOA of Minoxidil?
K+ channel opening
K+ efflux
hyperpolarisation
Ca2+ VGCs don’t open
