1. Diuretics Adverse effects of diuretes Hypokalemia: K*t depletion (except for potassium-sparing diuretcs); hypokalemia may be hazardous in persons taking digitalis, who have chronic arrhythmias, acute myocardial infarction or left ventricular dysfunction Restriction of dietary Nat intake will minimize K+ loss Mgz+ depletion; Impair glucose tolerance, induce hyperglycemia Increase serum lipid concentrations, induce hyperlipidemia; Hyperuricemia, precipitate gout
Adverse effects of diuretcs • Hypokalemia: K+ depletion (except for potassium – sparing diuretcs); hypokalemia may be hazardous in persons taking digitalis, who have chronic arrhythmias, acute myocardial infarction or left ventricular dysfunction. Restriction of dietary Na + intake will minimize K+ loss. • Mg 2+ depletion; • Impair glucose tolerance, induce hyperglycemia; • Increase serum lipid concentrations, induce hyperlipidemia; • Hyperuricemia, precipitate gout;
2. Sympathoplegic agents c 2. Nucleus of the tractus solitarius Brail enso 1. Baroreceptor in carotid sinus Inhibitory interneurons XI Sedation, mental depression, sleep Arterial blood pressure disturbance, dry mouth, analgesia 3. vasomotor Spinal More selective action Inhibition o cord 4. Autonomic 5. Sympathetic parasympathetic regulation ganglIon nerve ending 6.aor阝 profound sympathetic receptor Similar like surgical sympathectomy blockade Figure 11-2. Baroreceptor reflex arc The antihypertensive effect of these agents used alone may be limited by retention of Nat by the kidney and expansion of blood volume. So sympathoplegic antihypertensive drugs are most effective when used concomitantly with a diuretc
The antihypertensive effect of these agents used alone may be limited by retention of Na + by the kidney and expansion of blood volume. So sympathoplegic antihypertensive drugs are most effective when used concomitantly with a diuretc. Sedation, mental depression, sleep disturbance, dry mouth, analgesia Inhibition of parasympathetic regulation, profound sympathetic blockade Similar like surgical sympathectomy More selective action
2. Sympathoplegic agents 1)Centrally acting sympathoplegic drugs 2) Ganglion blocking agents 3)Adrenergic neuron-blocking agents 4) Adrenoceptor antagonists(常用抗高血压药)
2. Sympathoplegic agents 1)Centrally acting sy mpathoplegic drugs Methyldopa(甲基多巴): metabolize to methy dopamine and a-methyInorepinephrine Its antihypertensive action appears to be due to timulation of central a adrenoceptors by a methy norepinephrine or a methldopamine
Methyldopa（甲基多巴）: metabolize to - methyldopamine and - methylnorepinephrine; Its antihypertensive action appears to be due to stimulation of central adrenoceptors by methylnorepinephrine or methldopamine
2. Sympathoplegic agents 1) Centrally acting sympathoplegic drugs Clonidine: After intravenous injection, it produces a brief rise in blood pressure(direct stimulation of a adrenoceptors in arterioles) and flowed by a more prolonged hypotension( stimulation of a adrenoceptors in medulla) Clonidine lowers heart rate and cardiac output more than methy ldopa Pharmacological roles: O-methylnorepinephrine and clonidine both bind more tightly to a, than to a adrenoceptors They bind to presynaptic a, adrenoceptor to reduce catecholamine release Bind to postsynaptic a, adrenoceptor to inhibit activity of appropriate neurons Clonidine also binds to nonadrenoceptor site, the imidazoline receptor Guanabenz and guanfacine: stimulat a adrenoceptor
Clonidine: After intravenous injection, it produces a brief rise in blood pressure (direct stimulation of adrenoceptors in arterioles) and flowed by a more prolonged hypotension (stimulation of adrenoceptors in medulla). Clonidine lowers heart rate and cardiac output more than methyldopa. Pharmacological roles: -methylnorepinephrine and clonidine both bind more tightly to 2 than to 1 adrenoceptors. • They bind to presynaptic 2 adrenoceptor to reduce catercholamine release • Bind to postsynaptic 2 adrenoceptor to inhibit activity of appropriate neurons. • Clonidine also binds to nonadrenoceptor site, the imidazoline receptor, Guanabenz and guanfacine: stimulat adrenoceptor