ORAL MEDICATIONS USED FOR MANAGEMENT OF HYPERTENSION

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ORAL MEDICATIONS USED FOR MANAGEMENT OF HYPERTENSION


Diuretics
Beta-Adrenergic Blockers
Central Acting Inhibitors
Peripheral-Acting Adrenergic Inhibitors
Non selective Alpha and Beta Adrenergic Blockers
Vasodilators
Angiotensin-Converting Enzyme (ACE) Inhibitors

DIURETICS

A. Thiazides and related sulfonamides

Mode of action:
increase the excretion of Na+, Cl-, and water by interfering with the
transport of sodium ions across the renal tubular epithelium
reduce blood pressure by decreasing cardiac output
Representative agent:
hydrochlorothiazide
Side effects:
xerostomia
increased thirst
orthostatic hypotension
polyuria
dizziness
fatigue, weakness

B. Loop diuretics (also called High-efficiency diuretics)

Mode of action:
inhibit Na+ and Cl- reabsorption in the descending limbs of the loop of Henle
enhance excretion of K+, Mg++, and Ca++.
reduce blood pressure by decreasing fluid volume and thereby reducing cardiac output
Representative agents:
furosemide
ethacrynic acid
bumetanide
Side effects:
xerostomia
increased thirst
lichenoid drug reaction
neutropenia
leukopenia
anemia
orthostatic hypotension
renal failure

C. Potassium-sparing agents

Mode of action:
competitive antagonism of the endogenous mineralocorticoid aldestrone change
pressure levels and reduce blood pressure by reducing total fluid volume
Representative agents:
amiloride
spironolactone (Aldactone)
triamterene
Side effects:
xerostomia
increase thirst
gingival bleeding (spironolactone)
lichenoid drug reaction

D. Carbonic anhydrase inhibitors

Mode of action:
inhibition of the enzyme carbonic anhydrase in the proximal and distal segments of the renal tubule so as to allow diuresis
reduce blood pressure by decreasing fluid volume and thereby reducing cardiac output
Representative agents:
acetazolamide
dichlorphenamide
methazolamide
Side effects:
xerostomia
burning mouth, tongue, lips
parasthesia
metallic taste
thirst

BETA-ADRENERGIC BLOCKERS

Mode of action:
blocks b-1 and b-2 receptors in
cardiac effect: by blocking beta-1 receptors, reduces rate of SA node firing rate, slows the conduction through AV node, and reduces contractile strength and automaticity
in the vascular system, reduce blood pressure by reducing cardiac output and increasing peripheral resistance
Representative agents:
Acebutolol
atenolol
metoprolol
nadolol
penbutolol
pindolol
propranolol
timolol
Side effects
orthostatic hypotension
xerostomia
sore throat
nasal stuffiness
asthma
drowsiness
depression
fluid retention


CENTRAL-ACTING ADNERNERGIC INHIBITORS

Mode of action:
direct effect on alpha 2-adrenoceptor (sympathetic vasomotor center in CNS), which reduces impulses in sympathetic nervous system
reduces blood pressure by decreasing peripheral resistance and by decreasing plasma renin levels
Representative agents:
clonidine (Catapres)
methldopa (Aldomet)
guanabenz
guanfacine
Side effects:
xerostomia
taste changes
salivary pain or swelling
palpitation
ECG abnormalities
insomnia
anxiety
drowsiness

PERIPHERAL-ACTING ADRENERGIC INHIBITORS

Mode of action:
inhibits the active uptake of catecholamines into storage vesicles of the nerve terminal
decrease blood pressure by decreasing sympathetic tone, and by decreasing peripheral vascular resistance
Representative agents:
guanadrel
guanethidine
Rauwolfia alkaloids (e.g. reserpine)
Side effects:
xerostomia
bleeding
thrombocytopenia purpura
orthostatic hypotension
drowsiness, fatigue, weakness
Mode of action:
decrease total vascular resistance by vasodilation of arterioles and capacitance veins, by selective blocking of alpha 1-receptors on vascular smooth muscle
Representative agents:
selective alpha 1-adrenergic blockers
prazosin (Minipress)
terazosin (Hytrin)
Side effects:
xerostomia
orthostatic hypertension, postural dizziness
nausea, Gl upset
drowsiness, fatigue, weakness
anxiety, depression

NONSELECTIVE ALPHA- AND BETA- ADRENERGIC BLOCKERS

Mode of action:
competitive blocking of both a- and b- adrenergic receptors (greater affinity for b- receptors) on vascular smooth muscle
decrease blood pressure by decreasing peripheral vascular resistance
Representative agents:
labetalol (Normodyne, Trandate)
Side effects:
xerostomia
taste changes
orthostatic hypotension
nausea, Gl upset
nervousness
anxiety, depression
parasthesia
bronchospasm

VASODILATORS

Mode of action:
direct relaxation (vasodilation) of arteriolar smooth muscle
decrease blood pressure by decreasing peripheral vascular resistance
Representative agents:
hydralazine (Apresoline)
minoxidil (Loniten)
Side effects:
nasal congestion
lupus-like syndromes
leukopenia

ANGIOTENSIN-CONVERTING ENZYME (ACE) INHIBITORS

Mode of action:
inhibits ACE preventing conversion of angiotension I to angiotensin II, resulting in dilation of arteriole, venous vessels
decrease blood pressure by removing the vasoconstricting effect of ACE and thereby decreasing peripheral vascular resistance
Representative agents:
captopril (Capoten)
enalapril (Vasotec)
lisinopril (Zestril, Prinivil)
Side effects:
xerostomia
loss of taste
angiodema
glossitis
oral ulceration (Stevens-Johnson syndrome - captopril, enapril)
lichenoid drug reaction
renal insufficiency
Slow Channel Calcium-Entry Blocking Agents

Mode of action:
direct relaxation (vasodilation) of coronary and peripheral arteriolar smooth muscles by blocking Ca++ influx
Representative agents:
verapamil (Calan, Isoptin)
dilitiazen
nifedipine (Adalat, Procadia)
nitrendipine
Side effects:
gingival hyperplasia
xerostomia
orthostatic hypotension
light-headedness, nausea
edema
flushing, skin reactions
congestive heart failure