ANS Drug side effects Flashcards
Clonidine - side effects
sedation, xerostomia, sexual dysfunction
abrupt withdrawal associated w/ rebound inc sympathetic tone –> rebound HTN, sweating, headache, tachycardia, abd pain, nervousness
Methyldopa - uses
Not 1st line HTN but safe in pregnancy!
Amphetamine
analeptic, dec appetite (but tolerance develops rapidly), contracture of urinary sphincter (useful for incontinence)
D isomer more potent for CNS
L isomer more potent for CV
Ephedrine uses
relaxes brachial smooth muscle
mydriasis w/o affecting accomodation after local administration
phenoxybenzamine
converted to highly reactive intermediate that covalently binds & inactivates alpha
irreversible, insurmountable, noncompetetive
blockade is slow developing but long lasting (3-4 days)
no intrinsic activity
Phentolamine
competetive, reversible antagonism
most effective antagonizing circulating catecholamine
degree of antagonism is directly proportional to alpha adrenergic tone
dec BP if supported by sympathetic activity or sympathomimetics
Prazosin
favorable changes in blood lipid chemistry –> dec total cholesterol, dec TGs, inc HDL
“first dose effect” - postural htn & syncope with 1st dose or inc dosing
Adrenergic amines: uses
decongestant, combo w/ local anesthetic, local tissue hemostasis, hypotension, shock, mild-moderate herat failure, cardiac arrest, bronchial asthma, severe allergic rxn (anaphylactic shock), opthalmology (mydriasis & wide angle glaucoma)
alpha antagonists: uses
acute hypertensive crisis, essential hypertension, raynaud’s syndrome, combo w/ BB pre & operatuve management of pheochromocytoma, benign prostatic hyperplasia (BPH)
Beta blockers
competitive antagonists
effects proportional to beta adrenergic tone (inc tone in exercise & myocardial inadequacy)
Some have membrane stabilizing effect
weak intrinsic activity (pindolol)
Lipophilic BBs
typically hepatic clearance
longer half life
penetrate BBB so more neurologic SEs
Hydrophilic BBs
typically renal clearance
shorter half life
poorer penetrance through BBB
B1 blockade effects
dec HR, SV, CO, AV conduction
B2 blockade effects
block B2 vasodilation supported by iso or epi
block B2 bronchodilation –> inc resistance to airflow, precipitate asthma attack in asthmatic or COPD pts
Adverse effects/contraindications of BBs
severe bradycardia, heart block, asthma attack, raynaud’s, withdrawal syndrome with abrupt discontinuation (rebound HTN, exacerbate anginal attacks, supersensitivity to exogenous B-agonists)
