Adrenergics & Anti-adrenergics Flashcards
What are adrenergic drugs?
Sympathomimetic drugs – mimic the action of adrenaline or noradrenaline released by the nervous sytem
What are the two structural types of direct adrenergic drugs?
Catecholamines (similar structure to endogenous adrenaline) and non-catechol
What are the adrenergic receptors?
Alpha 1, 2 & Beta 1, 2 ,3
What is an alpha-1 selective adrenoreceptor agonist?
Phenylephrine
What is an alpha-2 selective adrenoreceptor agonist?
Brimonidine
What is a non-selective alpha receptor agonist?
Oxymetazoline
What is both an alpha 1 and beta 1 agonist?
Dopamine
What is a beta-1 selective adrenoreceptor agonist??
Dobutamine
What are two beta-2 selective adrenoreceptor agonists?
Salbutamol and Terbutaline
What is a beta-3 selective adrenoreceptor agonist?
mirabergon
What are two non-selective sympathomimetic drugs?
Epinephrine & norepinephrine
Is it possible to have complete selectivity for beta receptors? Why?
No - the receptors are structurally similar, so selectivity is dose-dependent
What is oxymetazoline used for and why?
Used topically to reduce mucus – causes vasoconstriction of nasal mucosa.
Has little systemic absorption so few side effects
Can phenylephrine be taken orally?
Yes, due to its selectivity – unlikely to have unwanted adverse effects due to activation of other receptors
Name the important receptors and the organs/functions they are specific to.
A2 receptors mediate secretions, B1 receptors mediate the heart and B2 receptors mediate the lungs
Why is isoprenaline not really used now?
It is non-selective. When used to treat asthma by activating beta 2 receptors, it causes unwanted tachycardia by activating beta 1 receptors
What is a drug used to treat urinary incontinence and what is its mechanism of action?
Mirabergon. It activates b3 receptors and causes bladder relaxation
What is dopamine used for and why?
Severe heart failure. Acts on alpha 1 receptors to cause peripheral vasoconstriction, shunting blood to the important organs. Acts on b1 receptors to stimulate the heart.
What is an adrenoreceptor agonist used to treat glaucoma?
Brimonidine. It is a selective a2 receptor activator. It induces vasoconstriction in the eye and reduces secretion of intraocular fluid, decreasing intraocular pressure. It also has a cytoprotective effect in the eye, slowing death of the retinal ganglia.