Bronchodilating Drugs Pat Woodbery, ARNP, CS Professor of Nursing.
Anti-hypertensive drugs for Nursing Students
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Transcript of Anti-hypertensive drugs for Nursing Students
INTRO
Hypertension is defined as either a sustained systolic blood pressure (SBP)of greater than 140 mm Hg or a sustained diastolic blood pressure of greater than 90 mm of Hg.
An agent that reduces high blood pressure is called as an ANTIHYPERTENSIVE.
Prehypertension-systolic between 120 to 139 mm/Hg and diastolic between 80 to 89 mm/Hg.
Effects of Hypertension Increases risk of heart disease , heartfailure, kidney
disease, blindness, and stroke. Primary Hypertension- No known reason.Secondary Hypertension-due to some cause such as
kidney disease, abnormalities of adrenal glandswill try nonpharmacological methods first.
CLASSIFICATION DIURETICS Thiazide Type:
Hydrochlorothiazide,Chlorothalidone,Bendroflume-thiazide,Trichloromethazide
Potassium Sparing: Spironolactone,Amiloride,Triamterene
Loop Diuretics: Furosemide,Ethacrynic Acid,Bumetanide,Torasemide
ACE INHIBITORSCaptopril,enalapril,lisinopril,perindopril,r
amipril.ANGIOTENSIN ANTAGONISTSLosartan,irbesartan,candesartan
CLASSIFICATION (Cont...)Sympatholytics:Centrally acting drugs – Clonidine and
Methyl dopa.Ganglionic blockers – TrimethaphanAdrenergic Neuron Blockers – Resperpine,
Guanithidine.ß - ADRENERGIC BLOCKERSPropranolol,metaprolol,atenolol.+ß ADRENERGIC BLOCKERSLabetalol,carvedilol. - ADRENERGIC BLOCKERSprazosin.,terazosin,phentolamine
CLASSIFICATION (Cont....)CALCIUM CHANNEL BLOCKERSVerapamil,diltiazam,nifedipine,felodipine,
amlodipine,lacidipineVASODILATORSHydralazine,minoxidil, sodium
nitroprusside.
DIURETICS
It enhance the excretion of Na and Water resulting in in plasma volume - Cardiac Output - BP Body Na – Relaxation of vascular smooth muscles
- BP Thiazides are the first line anti hypertensives and
are in expensive, it combined with K+ sparing diuretics is the best way to avoid hypokalemia.
Loop Diuretics – It is a powerful diuretics their antihypertensive effect is low. It is used only in hypertension with chronic renal failure or congestive cardiac failure.
ACE (Angiotensin Converting Enzyme Inhibitors)
Angiotensin II is a powerful vasoconstrict aldosterone also raises the BP by increasing the blood plasma volume.
ACE inhibitor prevent the formation of angiotensin II and (indirectly Aldosterone) there is vasodilation and decreased in peripheral vascular resistance, resulting in BP fall.
Vasoconstriction
Increase in BP
Salt & water retention
Blood Volume
Pharmacokinetics
ACE inhibitors well absorbed(except captopril and lisinopril)
ACE Inhibitors are excreted through
kidney
AE 1.Persistent dry cough due to bradykinin level is
more common in women. 2.Hypotension,head ache,nausea, abdominal pain 3.Hyperkalemia ,proteinuria,neutropenia 4.Dysgeusia (an altered taste sensation) is more
common in captopril. 5.Angioneurotic edema- ACE inhibitors rarely
cause angioedema with swelling in the lips ,nose, larynx and airway obstruction.
6.skin rashes 7.Teratogenicity
USES 1.Hypertension
2.congestive cardiac failure (CCF )
3.myocardial infarction
4.coronary artery disease
5.chronic renal failure
6.Scleroderma renal crisis
PRECAUTION AND CONTRAINDICATION ACE Inhibitors are contraindicated in
pregnancy.
It should not be combined with K Sparing
diuretics.
At the first sign of angioedema ,ACE should be
stopped.
ACE Inhibitors may enhance the plasma level of
digoxin.
Angiotensin II Receptor Blocker Losartan was the 1st orally effective AT 1 receptor
antagonist. There are 2 sub types of Angiotensin - II
receptors – AT1 & AT2 AT1 receptor are present in vascular and
myocardial tissue, brain, kidney and adrenal glomerular cells.
Losartan has high affinity for AT1 receptors when compared to AT2 receptors.
By blocking AT1 receptors Losartan blocks the effect of angiotensin II.
Angiotensin II Receptor Blocker (Cont....) It relaxes vascular smooth muscles,
promotes salt and water excretions and reduces plasma volumes, hence the BP also decreased.
Pharmacokinetics Given Orally
Bioavailability is < than 50 %
All extensively protein bound
Excreted by kidney
Angiotensin II Receptor Blocker (Cont....) Adverse Effects – Hypotension,
Hypokalemia, Angioedema is rare. Uses:
HT (First line drug of choice) Cardiac Failure
Renin Antagonist Aliskiren is a direct renin inhibitor
and was recently introduced. It blocks the effect of renin and there by reducing the BP.
Dose: 150 – 300 mg once daily.
Sympatholytics These are the drugs acting centrally. Clonidine is a selective 2 agonist. Stimulation of 2 receptors in the CNS. (in the
vasomotor center and hypothalamus) Decrease the central sympathetic outflow, blocks
the release of NA from the nerve terminals, leading to fall in BP.
AE includes drowsiness, dryness of mouth, nose and eyes. Swelling of parotid gland and pain.
Uses – Mild – Moderate HT, Opioid Withdrawal, diabetic neuropathy, with anaesthetics.
Methyl Dopa is a pro drug, is metabolized in the body to methyl nor ephinephrine, which is an 2 agonist. It reduces central symapthetic outflow leading to a fall in BP.
Uses – Mild - Moderate HT along with Diuretics. It is safe in HT during pregnancy.
Ganglionic Blockers This drugs blocks both symathetic and para
sympathetic ganglions resulting in decreased sympathetic tone and a fall in BP. Trimethaphan is the only ganglion blocker.
Used for surgeries in IV route.
Adrenergic Neuron Blocker Guanethidine depletes the stores of NA
in the adrenergic neuron and also blocks its release.
It is not used because of its AE. Reserpine is an alkaloid obtained from
‘Rauwolfia serpentina’. It destroys vesicles that store NA and thus depletes the store of these mono amines and reduces the BP.
Adrenergic Receptor Blockers Blockers 1. Non – Selective Blockers like Phenoxybenzamine and
phentolamine are used in the treatment of HT.
Adrenergic Receptor Blockers Blockers 2. Selective 1 Blockers like Prazosin, Terazosin dilates
both aterioles and venules. Peripheral vascular resistance is decreased leading in fall in BP.
These are mild anti hypertensives. It blocks the 1 receptors results in decreased myocardial contractility and cardiac output. Thus they reduce the BP.
Atenolol is the preferred Beta blockers.
- Blockers
Advantage of atenelol is once a day dosing.
Absence of CNS side effects is other advantage
Esmolol is the short acting beta blockers, used in intra
operative and post operative hypertension.
& Blockers
Labetalol and Carvedilol block 1 and receptors.
It is used in IV, in the treatment of Hypertensive
emergencies.
Calcium Channel BlockersThey are another important group of anti hypertensives.They dilate the arterioles resullting in reduced
peripheral vascular resistance.Nifedipine produce some refelex bradycardia while this
is not seen with Verapamil and Diltiazem as they are cardiac depressants.
Uses: it is effective particularly in elderly patients.It may be used in monotherapy in moderate to severe
HT.It is used in sub lingual route for Hypertensive
emergencies.
Vasodilators It relax the vascular smooth muscles. Thus
reducing the BP. Due to decreased peripheral vascular resistances.
Hydralazine is directly acting arteriolar dilators. The fall in BP is associated with Tachycardia. Adverse Effects Headache, Nausea, Hypotension, Flushings, dizziness and
Palpitation , water retention.
Uses: It is used with beta blockers and diuretics in moderate – severe HT.
Vasodilators (Cont...) Minoxidil is directly acting arteriolar dilators. In
severe HT not responding to other drugs. It acts by opening K + channel in the smooth muscles resulting in reuced BP.
Diazoxide is directly acting potent arteriolar dilators. It can cause hyperglycemis because it inhibits the insulin secretion
Sodium Nitroprusside is the rapidly acting vasodilators. It relaxes both arterioles and veneules.
AE – Palpitations, Sweating. Nausea and vomiting, Hypotension.
Uses - drug of choice for HT emergencies. MI
NURSING IMPLICATIONS Risk of fall is evident as vasodilators can cause
postural hypotension. So the patients must be guarded while getting up.
Palpitations can be due to reflex tachycardia induced by a vasodilators.
Sodium nitroprusside acts with in a seconds. BP monitored constantly. It should be disolved in 2 ml of 5 % dextrose
solution. And than diluted in IV fluids.
NURSING IMPLICATIONS
It is light sensitive, so protected from light by an opaque wrapping.
If color changes infusion should be discarded.
Infusion is prolonged blood level of CN and thiocyanate should be checked.
It should not be prolonged for more than 2 – 3 days.