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Week-5 ------ 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

VASOCONSTRICTORS
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-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