Pharmacology Flashcards
Pharmacology
The study of biological effects of chemicals
Pharmacotherapeutics
clinical pharmacology, the branch of pharmacology that uses drugs to treat, prevent, and diagnose disease.
Pharmacokinetics
how the body acts on the drug
Absorption
what happens to a drug from the time it enters the body until it enters the circulating fluid; intravenous administration causes the drug to directly enter the circulating blood, bypassing the many complications of absorption from other routes
pharmacodynamics
the study of the interactions between the chemical components of living systems and the foreign chemicals, including drugs, that enter living organisms; the way a drug affects a body
Distribution
movement of a drug to body tissues; the places where a drug may be distributed depend on the drug’s solubil- ity, perfusion of the area, cardiac output, and binding of the drug to plasma proteins
Pharmacogenomics
the study of genetically determined variations in the response to drugs
first pass effect
a phenomenon in which drugs given orally are carried directly to the liver after absorption, where they may be largely inactivated by liver enzymes before they can enter the general circulation; oral drugs frequently are given in higher doses than drugs given by other routes because of this early breakdown
critical concentration
the concentration a drug must reach in the tissues that respond to the particular drug to cause the desired therapeutic effect
4 usual drug fxn.’s
- Replace missing chemical. 2. Increase or stimulate cellular activity (agonist). 3. Decrease or repress cellular activity (antagonist). 4. Interfere with cellular activity of foreign cells (chemotherapeutic effect) (antibiotics)
agonists
Directly interact with receptor sites to cause the same activity that natural chemicals would cause at that site. eg: Insulin
Antagonist
act to prevent the breakdown of natural chemicals that are stimulating the receptor site. eg: MAO inhibitors.
Selective Toxicity
The ability of a drug to attack only those systems found in foreign cells
Alpha1 receptor
Vasoconstriction, increased peripheral vascular resistance=^BP, contracted pilorection muscles, thickened saliva, male sexual emission, pupil dilation, closed urinary sphincter
Alpha2
Prevents overstimulation of effector. Sites. Moderates insulin release by beta cells of pancreas.
Beta1
^ heart acticvity
Beta2
Vasodilation
Brochodilation
Location of alpha 1
Iris, blood vessels, urinary bladder
Location of alpha2
On nerve membranes
Beta1
Cardiac tissue
Beta2
Smooth muscle of blood vessels, bronchi, in periphery and in uterine muscle
Sympathomimetic drugs
Adrenergic agonist
Mimics the effects of the SNS
Treatments for shock, ophthalmic solution to dilate pupil, asthma
Dopamine indications
Correction of hemodynamic imbalances present in shock.
Alpha and beta adrenergic agonists
Dobutamine treatment of HF
Ephedrine treats hypotension
Epinephrine treat shock bronchospasm prolong vasoconstriction for anesthesia
Norepinephrine treat shock cardiac arrest
Alpha specific adrenergic agonists
Clonidine treats essential hypertension, chronic pain, opiate withdrawal
Midodrine treats orthostatic BP
Phenylephrine cold/allergy glaucoma potent vasoconstictor
Labetalol indications/uses
Hypertension, control of BP with pheochroocytoma. Clonidine withdrawal.
Labetalol actions
Competitively blocks alpha and beta receptors in SNS. Causes >BP without reflex tachycardia and >renin levels
Labetalol adverse effects
Dizziness, vertigo, fatigue, gastric pain, fart, impotence, bronchospasm, dyspnea, cough, >exercise tolerance
contraindications for labetalol and other non specific adrenergic blockers
Bradycardia, heart blockages, asthma, bronchospasm, shock or HF, diabetes, preg/lact
Pheochromocytoma
a tumor of the chromaffin cells of the adrenal medulla that releases norepinephrine and epinephrine. Causes Hypertension and tachycardia.
Dopamine Actions
Acts directly Increasing HR, BP stimulates SNS response. Releases norepinephrine from sympathetic nerve terminals; mediates dilation of vessels in the renal and splanchnic beds to maintain renal perfusion. Protecting kidney.
Dopamine Adverse effects
Tachycardia, ectopic beats, anginal pain, hypotension, dyspnea, nausea, vomiting, headache.
Teaching points of non-specific adrenergic blockers
- discontinue herbal/otc drugs that interact ie: gensing, sage, xuan shen, nightshade etc.
- Don’t abrubtly stop taking (2 wk. wean)
- slow movements such as standing and sitting.
- cautions with driving/machinery.
Drug reactions with non-specific adrenergic blockers
risk of hypotension if combined with volatile liquid general anesthetics eg: enflurane, halothane, or isoflurane. The effectiveness of diabetic agents is increased, leading to hypoglycemia. carvedilol-conduction system disturbances when combined with verapamil or diltiazem.
phentolamine
NONSELECTIVE ALPHA-ADRENERGIC BLOCKING AGENT: The only one still in use.
phentolamine indications
Prevention/control of hypertensive episodes associated with pheochromocytoma; test for diagnosis of pheochromocytoma; prevention and treatment of dermal necrosis and sloughing associated with IV extravasation of norepinephrine or dopamine.
phentolamine Actions
Competitively blocks postsynaptic alpha1- and presynaptic alpha2-receptors, causing a vasodilation and lowering of blood pressure, accompanied by increased reflex tachycardia.
Phentolamine Contraindications
CAD, MI, Cautions: Preg/Lact.
Phentolamine Adverse effects
Acute and prolonged hypotensive episodes, MI, tachycardia, arrhythmias, nausea, flushing.
The alpha1-selective adrenergic blocking agents contraindications (Doxazosin or Prazosin)
used cautiously with HF or renal failure because of blood pressure–lowering effects. Hepatic impairment could alter the metabolism. Allegy, Preg/Lact.
The alpha1-selective adrenergic blocking agents indications Doxazosin
Treatment of mild to moderate hypertension as monotherapy or in combination with other antihypertensives; treatment of benign prostatic hypertrophy.
Doxasozin Actions
Reduces total peripheral resistance through alpha blockade; does not affect heart rate or cardiac output; increases high-density lipoproteins while lowering total cholesterol levels.
*relaxation of the bladder and prostate and improved flow of urine in male patients
Doxasozin Adverse effects
Headache, fatigue, dizziness, postural dizziness, vertigo, tachycardia, edema, nausea, dyspepsia, diarrhea, sexual dysfunction.
The alpha1-selective adrenergic blocking agents Drug Interactions ( Doxazosin)
hypotensive effects may occur if these drugs are combined with any other vasodilating or antihyper- tensive drugs, such as nitrates, calcium-channel blockers, and angiotensin-converting-enzyme inhibitors.
NONSELECTIVE BETA-ADRENERGIC BLOCKING AGENTS (Propanolol) Indications
Widely Used to treat CV problems and to prevent reinfarction after MI. Hypertension, angina pectoris, idiopathic hypertrophic subaortic stenosis, supraventricular tachycardia, tremor; adjunctive therapy in pheochromocytoma; prophylaxis of migraine headache; management of situational anxiety.
Action of NONSELECTIVE BETA-ADRENERGIC BLOCKING AGENTS (Propanolol)
Competitively blocks beta-adrenergic receptors in the heart and juxtaglomerular apparatus; reduces vascular tone in the central nervous system.
>HR, contractility, and excitability, as well as a membrane-stabilizing effect, lead to a decrease in arrhythmias, a decreased cardiac workload, and decreased oxygen consumption. The juxtaglo- merular cells are not stimulated to release renin contributing to >BP.
Adverse effects of NONSELECTIVE BETA-ADRENERGIC BLOCKING AGENTS (Propanolol)
Allergic reaction, bradycardia, HF, cardiac arrhythmias, CVA, pulmonary edema, gastric pain, Fart, impotence, decreased exercise tolerance, bronchospasm.
contraindications of NONSELECTIVE BETA-ADRENERGIC BLOCKING AGENTS (Propanolol)
bradycardia, heart blocks, shock, or HF, which could be exacerbated by the cardiac-suppressing effects; with bronchospasm, ; CAUTION: diabetes and hypoglycemia because blocking of the normal signs and symptoms of hypoglycemia and hyperglycemia; with thyrotoxicosis because of the adrenergic blocking effects on the thyroid gland; or with renal or hepatic dysfunction, which could interfere with the excretion and metabolism of these drugs.
Caution COPD, or acute asthma, which could worsen due to the blocking of the sympathetic bronchodilation
Drug Interactions of NONSELECTIVE BETA-ADRENERGIC BLOCKING AGENTS (Propanolol)
- paradoxical hypertension occurs when beta- blockers are given with clonidine, and increased clonidine withdrawal may also occur.
- decreased antihypertensive effect occurs if beta- blockers are given with NSAIDs
- initial hypertensive episode followed by bradycardia with epinephrine.
- Peripheral ischemia beta-blockers with ergot alkaloids.
- With insulin or other anti-diabetic agents, there is a potential for change in blood glucose levels. And a Masked symptom effect.
Indications of Beta1-selective adrenergic blocking agents (atenolol)
Beta1-selective adrenergic blocking agents do not block the beta1-receptors that are responsible for bronchodilation and therefore are preferred in patients with respiratory problems. ■ Beta1-selective adrenergic blocking agents treat hypertension and angina, HF, MI; off-label uses are prevention of migraine headaches, alcohol withdrawal syndrome, and supraventricular tachycardias.
Adverse effects of Beta1-selective adrenergic blocking agents (atenolol)
Allergy, dizziness, sleep disturbances, memory loss, and disorientation. bradycardia,HF, arrhythmias, gastric pain, Fart, impotence, dysuria, bronchospasm, decreased exercise tolerance.
Contraindications of Beta1-selective adrenergic blocking agents (atenolol)
Allergy, sinus bradycardia, heart block, cardiogenic shock, HF, or hypotension, Preg/Lact. CAUTION: diabetes, thyroid disease, or COPD.
Drug Interactions with Beta1-selective adrenergic blocking agents (atenolol)
- decreased hypertensive effect occurs if these drugs are given with clonidine, NSAIDs, rifampin, or barbiturates.
- initial hypertensive episode followed by bradycardia if these drugs are given with epinephrine.
- Increased serum level and toxicity of IV lidocaine. *risk for orthostatic hypotension with prazosin.
- increased effects if taken with verapamil, cimetidine, methimazole, or propylthiouracil
Adrenergic Blocking or Sympatholytic drugs
*lyse, or block, the effects of the SNS
*Therapeutic and adverse effects
Related to their ability to react with specific adrenergic receptor sites without activating them
*Action-
Prevent norepinephrine from activating the receptor
Carvedilol (Coreg)
hypertension and congestive heart failure (adult)
Guanadrel (Hylorel):
hypertension in adults not responding to thiazide diuretics
Guanethidine (Ismelin):
hypertension and renal hypertension
Labetalol (Normodyne, Trandate):
hypertension, pheochromocytoma, and clonidine withdrawal
Phentolamine (Regitine) Non-selective Alpha blocker
- Diagnosis of pheochromocytoma-rare tumor of the adrenal gland that causes toomuch release of epinephrine and norepinephrine
- Management of severe hypertension during pheochromocytoma surgery
- Prevention of cell death with IV infiltration of norepinephrine or dopamine
Phentolamine (Regitine) Non-selective Alpha blocker DRUG Interactions
Ephedrine, Epinephrine, Alcohol
Doxazosin (Cardura):
used to treat hypertension; also effective in the treatment of benign prostatic hypertrophy
Drug Interactions with Vasodilators and antihypertensives.
Prazosin (Minipress):
used to treat hypertension, alone or in combination with other drugs. Drug Interactions with Vasodilators and antihypertensives
Terazosin (Hytrin):
used to treat hypertension as well as BPH. Drug Interactions with Vasodilators and antihypertensives
Tamsulosin (Flomax) and alfuzosin (Uroxatral):
used in the treatment of BPH only Drug Interactions with Vasodilators and antihypertensives
Propranolol (Inderal)-
HTN, angina, migraine. Essential tremor
Sotalol (Betapace, Betapace AF)-
Betapace used in prevention of life-threatening ventricular arrhythmias, Betapace AF used in maintenance of NSR in afib/aflutter pts
Timolol (Timoptic)-
HTN, prevention of reinfarction after MI, migraine prophylaxis, reduces IOP in open-angle glaucoma in the opthlamic form
Nadolol (Corgard)-
HTN, chronic angina
Nebivolol (Bystolic)-
HTN
Beta1 selective beta blockers
***Preferred for patients who smoke or have asthma, obstructive pulmonary disease, or seasonal or allergic rhinitis
Because Do not usually block beta2-receptor sites, including the sympathetic bronchodilation
Atenolol (Tenormin)-
MI, chronic angina, HTN
Bisoprolol (Zebeta)-
HTN
Metoprolol (Lopressor, Toprol XL)-
HTN, CHF, MI
Esmolol (Brevibloc)-
Tx of supraventricular tachycardias (aflutter/afib)
Beta1 Selective adrenergic blockers drug to drug interactions
NSAIDs
IV lidocaine
Drug of choice for adult with HTN
Bisoprolol
Drugs used to treat HTN in Children
prazosin is used to treat hypertension, and phentolamine, which is used during surgery for pheochromocytoma.
Adrenergic blockers associated with more CNS adverse effects
pranolol and metoprolol
Drug-food
VitK -Coumadin
Dairy/ca2+-tetracycline
Drug-lab tests
Carbenicillin-=>serum na+
Fragmin= >increase AST liver fx.