Sympatholytic drugs Flashcards
Sympatholytic drugs used hypertension
α-adrenoceptor antagonists
β-adrenoceptor antagonists
Centrally acting α2-adrenoceptor agonists
α-adrenoceptor antagonists - cardiovascular effects
PVR: Decrease
Activate RAA
Left ventricular hypertrophy: Decrease
β-adrenoceptor antagonists - cardiovascular effects
Cardiac output: decrease
Plasma renin activity: decrease
Left ventricular hypertrophy: decrease
Centrally acting α2-adrenoceptor agonists - cardiovascular effects
PVR: Decrease
Blood volume: increase (except guanfacine)
Plasma renin activity: decrease
Left ventricular hypertrophy: decrease
α-adrenoceptor antagonists - effect on potassium and cholesterol
Total cholesterol: Decrease
LDLs: Decrease
HDLs: Increase
TGs: Decrease
α-adrenoceptor antagonists - adverse effects
Dizziness, first-dose syncope, fluid retention, orthostatic hypotension.
Selective α1-blockers: Reflex activation of sympathetic nervous system (increased HR, contractile force, NE levels, oxygen demand).
β-adrenoceptor antagonists - adverse effects
Bradycardia, bronchoconstriction, depression, fatigue, impaired glycogenolysis, vivid dreams, orthostatic hypotension, hepatic, renal and hematopoietic toxicity. Reduced exercise capacity.
α- and β-adrenoceptor antagonists - interactions
β-adrenoceptor antagonists: Cardiac depression is increased by diltiazem and verapamil. Hypotensive effect decreased by NSAIDs.
α-adrenoceptor antagonists: Hypotensive effect is increased by β-adrenoceptor antagonists and diuretics.
Selective α1-blockers - indications and contraindication in hypertension
NOT initial treatment. Added to other drugs if not properly cotrolled.
Selective α1-blockers used for HT
Doxazosin
Prazosin
Terazosin
β-blockers - MOA and indications HT
MOA: Decrease HR and contractility, inhibit renin secretion.
Indications: HT with cardiovascular diseases (e.g. coronary heart disease)
Carvedilol - indications in HT and reason for this indication
Diabetes - may improve insulin sensitivity.
Selective β1-blockers used in HT
Atenolol, bisoprolol, metoprolol
Atenolol - advantages
Fewer nervous system side effects
Labetalol - indications and adverse effects
Indications: Chronic hypertension, hypertensive emergencies
Adverse effects: Orthostatic hypotension
Esmolol - indication - adm - reason for indication
Adm IV. HT in surgery and hypertensive emergencies. Is a ultrashort-acting β1-blocker.
Third-generation α and β-blockers
Carvedilol.
Nebivolol.
Nebivolol - indications
HT in heart failure, diabetes, cardiac arrhythmias.
Nebivolol - effects
Selective β1-blocker.
Antioxidant properties.
Increases NO from endothelial cells.
Centrally acting sympatholytics
Clonidine
Guanfacine
Methyldopa
Clonidine, guanfacine, methyldopa - adverse effects
Dry mouth, fatigue, rebound hypertension, sedation, decreased mental acuity. These adverse effects are milder in guanfacine than clonidine.
Methyldopa: Autoimmune hemolytic anemia, hepatitis, lupus-like syndrome.
Clonidine, guanfacine, methyldopa - interactions
Tricyclic antidepressants - decrease hypotensive effect.
CNS depressants - increased sedative effect.
Methyldopa: Levodopa cause increased hypotensive effect.
Centrally acting sympatholytics - MOA
Reduce sympathetic outflow by activation of central α2-adrenoceptors in medulla. This reduces vascular resistance, little effect on HR and cardiac output.
Centrally acting sympetholytics - contra and why
Abrupt discontinuation - severe rebound hypertension.
Tricyclic antidepressants - block effect of these sympatholytics.
Clonidine - Not used for chronic treatment because of more side effects.
Clonidine and methyldopa- indications
Hypertensive emergencies. Symptoms of alcohol, opioid or nicotine withdrawal.
Methyldopa: HT in pregnancy
