Week MR160 the Circulatory System Chapter 20

CIRCULATORY overview HEART innervated muscle tissue BLOOD VESSELS - Pulmonary - Systemic - Coronary *************************** see Fig. 20-1

Drug affects on the HEART RATE RHYTHM (heartbeat) OUTPUT (volume of blood pumped) STRENGTH of contraction ENERGY production of the heart muscle ----‘Cardiac’ drugs mainly used to treat---- Heart-failure(CHF), Myocardial-infarction(MI), & Arrythmias

Heart failure (CHF) Congestive heart failure (CHF) Blood not being circulated at sufficient rate to meet body’s demands –pooling- Suspected when patient must elevate upper-body to breathe while lying down the REMEDY? * increase ‘strength-of-contraction’ and * reduce excess water, blood-volume Why would these things help?

DRUGS for heart failure … INOTROPIC’s (digoxin, digitalis) strengthen ‘squeezing’, contraction DIURETIC’s (hctz, furosemide) reduce blood-volume, heart’s ‘load’ … imagine pushing a boulder uphill! ACE’s (enalapril, lisinopril, quinapril) increases energy in cardiac-muscle

ARRHYTHMIAS SA(sino-atrial)node - natural pacemaker, controls heart’s RATE and RHYTHM Generates tiny ELECTRICAL impulses that cause contraction Arrhythmia is any disturbance of ‘normal’ Fast, slow, or erratic (unpredictable!) the REMEDY? ** stabilize these electrical-impulses !

DRUGS for arrhythmia Called anti-arrhythmics (of course!) Pacerone, Cardarone (amiodarone) Betapace (sotalol) Quinidine sulfate Norpace (disopyramide) Tikosyn (dofelitide) Lidocaine Hcl --- IV, injectable

VASOCONSTRICTORSVASOCONSTRICTORS Constrict (tighten) blood vessel walls used primarily to Stop SUPERFICIAL BLEEDING Relieve NASAL CONGESTION Raise BLOOD PRESSURE Increase FORCE of the heart’s action * epinephrine – powerful constrictor! * Afrin – constricts nasal vessels

VASODILATORS RELAX blood vessels, increasing diameter used to treat Hypertension (reduces BP) Heart conditions (**NTG for angina & chest-pain) Peripheral VASCULAR disease ** nitrates & nitrites – nitroglycerin (NTG) sublingual, transdermal patch, cream/oint.

Anti-HYPERTENSIVESAnti-HYPERTENSIVES BETA blockers * atenolol(Tenormin, Toprol-XL) ALPHA blockers * doxazosin(Cardura), terazosin(Hytrin) CALCIUM CHANNEL blockers * amlodipine(Norvasc), nifedipine(Procardia) central ALPHA agonists * clonidine(Catapres tablets & patches)

Drugs affecting the BLOOD COAGULANTS * vitamin-K (Mephyton)- fat soluble vitamin * calcium salts (gluconate, chloride, lactate) AntiCOAGULANTS ---many DDI’s (see Box 20-1 on page 102) Heparin – injectable Lovenox – self-administered injectable Coumadin(warfarin) – oral tablets

Cholesterol Lowering agents known as the antiLIPIDEMIC’s because they reduce overall lipid (cholesterol) levels in the blood (goal = <160mg/dL) HDL = ‘good cholesterol’ (> 30) *carries cholesterol to the liver for storage LDL = ‘bad cholesterol’ (< 70) *carries cholesterol from liver to the blood --- Dietary changes should be tried first NOT USED IN PREGNANCY! -----

ANTILIPIDEMICS – Drug Classes STATINS (HMG CoA reductase inhibitors) * atorvastatin (Lipitor) * lovastatin (Mevacor) * simvastatin (Zocor) * pravastatin (Pravachol) fibric acid derivatives (triglycerides/HDL) * gemfibrozil (Lopid) misc agents – ezetimibe (Zetia)

Autonomic Nervous System Let’s begin chapter-25 … the ANS made up of 2-parts: Sympathetic Parasympathetic * If one system stimulates a function, the other tends to inhibit it … they oppose each other see Table 25-1 for examples

Sympathomimetics (adrenergics) These agents ‘mimic’ the stimulation of the SNS (why ‘mimetic’ is in name) epinephrine (Adrenalin, Epi-Pen) * naturally produced by adrenal-glands * … “fight or flight” response (adrenergic) phenylephrine (Neo-Synephrine) * commonly found in NASAL SPRAYS for relief of nasal-congestion

sympathoLYTICs agents … … adrenergic BLOCKING agents are classified by the receptor which they’re most specific --- these drugs nullify stimulation of the SNS, so their effect is like stimulation of the PSNS! Alpha-blockers * methyldopa (Aldomet) Beta-blockers * propranolol (Inderal)

ParasympathoMIMETICS These “mimic” the effect of PSNS stimulation acetylcholine-like effects (ie, cholinergic) * bethanechol (Urecholine) * pilocarpine * neostigmine (Prostigmin) * edrophonium

parasympathoLYTICS Drugs that oppose or nullify the stimulation of the PSNS … so they have the same ‘net’ effect as stimulation of the SNS Also known as the ‘Cholinergic Blockers’ * atropine sulfate * clidinium bromide (Librax) * dicyclomine (Bentyl)

Hope you have a great week... let me know if you have any questions. -Dr. C