pharmacology

2009-08-31T21:00:00.000-07:00

DRUGS AFFECTING GASTROINTESTINAL SYSTEM

Antacids
Prototype :
- aluminum/magnesium compounds (Maalox)
- sodium bicarbonate (Alka-Seltzer)
- calcium carbonate (Tums)
- magnesium hydroxide (Milk of Magnesia).
Mechanism of actions :
- neutralize the stomach acidity.
Adverse effects :
- metabolic alkalosis, stone formation
- electrolyte imbalance
- diarrhea (magnesium), constipation (aluminum).
Nursing considerations :
- Give 1 hr after meals.
- Avoid giving medications within 1-2 hrs of antacid administration
(decreases absorption).
- Take fluids to flush after intake of antacid suspensions.
- Monitor for changes of bowel patterns.

Histamine – 2 blockers
Prototype :
- cimetidine (Tagamet), ranitidine (Zantac),
famotidine (Pepcid), nizatidine (Axid).
Mechanism of action:
- blocks H2 receptors in the stomach, reducing
acid secretions.
Nursing considerations :
- Given before or with meals
- Avoid giving other drugs with cimetidine
- Gynecomastia may developed with chronic use of cimetidine.

Proton – Pump Inhibitors (PPI)
Prototype :
- omeprazole (Losec), Lansoprazole (Lanz), pantoprazole (Pantoloc).
Mechanism of action :
- inhibit the proton H+ to combine with Cl- toform hydrochloric acid.
Nursing considerations :
- Given before meals preferably at morning.

Mucosal Barriers
Prototype :
- sucralfate (Carafate), misoprostol (Cytotec).
Mechanism of action :
- coats the mucosa to prevent ulcerations.
Nursing consideration :
- Given before meals.
- Misoprostol is contraindicated for pregnants.
- Sucralfate cause constipation

Anti-diarrheal Agents
Prototype :
- diphenoxylate (Lomotil), loperamide (Imodium), kaolin/pectin mixture (Kaopectate).
Mechanism of actions :
- decrease stomach motility and peristalsis.
Nursing considerations :
- Monitor for rebound constipation.
- Be cautious taking if with infectious diarrhea.
- Monitor atropine toxicity with diphenoxylate.
- Clay, white or pale stool is common with kaopectate.

Laxatives
a. lactulose (Cephulac), Na biphosphate (Fleet
enema) & magnesium salt (Milk of Magnesia)
- retain fluid and distend intestine
b. ducosate (Dialose)
- emulsify fecal fat and water
c. bisacodyl (Dulcolax) & senna (X-prep)
- irritates intestinal mucosa and
stimulate intestinal smooth muscles
d. bulk-forming laxative (Metamucil)
- increase fecal bulk and water content
e. mineral oil
- lubricates & prevent colon absorption

Emetics
Prototype : ipecac syrup, apomorphine
Mechanism of actions :
- induce vomiting through stimulation of vomiting center of medulla.
Indications :
- ingestion of poisonous or toxic substances.
Nursing considerations :
- Consult poison control center before induction of vomiting.
- Administer ipecac syrup with large amount of fluid

2009-08-31T20:54:00.000-07:00

RESPIRATORY MEDICATIONS

Bronchodilators
Prototype :
Symphatomimetic Xanthines
- albuterol, salbutamol - aminophylline
- isoproterenol, salmeterol - theophylline
- terbutaline

Mechanism of actions:
- sympathomimetic (b-receptor agonist) bronchodilators, dilate airways.
- xanthine bronchodilators, stimulate CNS for respiration.
Indications :
- bronchospasm, asthma, bronchitis, COPD.
Adverse effects :
- palpitations and tachycardia
- restlessness, nervousness, tremors
- anorexia, nausea and vomiting, headache, dizziness.
Nursing considerations :
- Contraindicated hyperthyroidism, cardiac dysrhythmia, or uncontrolled seizure
disorder.
- Should be used with caution in patient with HPN and narrow-angle glaucoma.

Glucocorticoids (Corticosteroids)
Prototype :
- dexamethasone, budesonide, fluticasone, prednisone, beclomethasone.
Mechanism of actions :
- act as anti-inflammatory agents and reduce edema of the airways, as well as
pulmonary edema.
Adverse effects :
- Cushing’s syndrome, neutropenia. osteoporosis
Nursing considerations :
- Take drugs at meal time or with food.
- Eat foods high in potassium, low in sodium.
- Instruct client to avoid individuals with RTI.
- Instruct client not to stop medication abruptly, it should be tapered to prevent
adrenal insufficiency
- Avoid taking NSAID while taking steroids.
- Take inhaled bronchodilators first before taking inhaled steroids, and rinse mouth
after using.

Mast Cell Stabilizers
Prototype : cromolyn sodium (Intal)
Mechanism of action :
- stabilize mast cells that release histamine triggering asthmatic attacks.
Nursing Consideration:
- Should be given before asthmatic attacks.
- Administer oral capsule at least 30 mins before meals for better absorption.
- Drink a few sips of water before & after inhalation to prevent cough & unpleasant taste
- Assess for lactose-intolerance.

Anti-histamines (H-1 blockers)
Protoytype :
- Astemizole (Hismanal), Loratidine (Claritin),
Brompheniramine (Dimetapp),
Diphenhydramine (Benadryl),
Cetirizine (Iterax), Celestamine (Tavist).
Mechanism of action :
- decrease nasopharyngeal secretions and decrease nasal itching by blocking histamine
in H1-receptor.
Indications :
- common colds, rhinitis, nausea and
vomiting, urticaria, allergies and as sleep aid.
Nursing Considerations :
- Administer with food and drink.
- Given IM via Z-track method or orally.
- Precautions in handling machine and driving while taking these drugs.
- Ice chips or candy for dry mouth

Anti-tuberculosis
Prototype :
First line Second line
- Isoniazid (INH) - Cycloserine
- Rifampicin (Rifadin) - Kanamycin
- Ethambutol - Ethonamide
- Pyrazinamide - Para-aminosalicylic acid
- Streptomycin

- active tuberculosis are treated with drug combination for 6-9 mos.
- multidrug-resistant strain (MDR-TB) are medicated for 1 year up to 2 years
- given before meals

Isoniazid
- should be given 1 hr before or 2 hrs after meals because food may delay absorption.
- should be given at least 1 hr before antacids.
- instruct to notify physician for signs of hepatoxicity (jaundice), and neurotoxicity
numbness of extremities.
- administer with Vitamin B6 to counteract the neurotoxic side effects.
- avoid alcohol.

Rifampicin
- given on an empty stomach with 8 0z. of water, 1 hour before or 2 hours after meals
and avoid taking antacids with medications.
- hepatotoxic thus avoid alcohol.
- instruct the client that urine, feces, sweat, and tears will be red-orange in color.

Pyrazinamide
- given for 2 months.
- increase serum uric acid and cause photosensitivity.

Ethambutol
- contraindicated in children under 13 years old.
- obtain a baseline visual acuity because it can cause optic neuritis.
- Instruct the client to notify the physician immediately if any visual problems occurs.

Streptomycin
- aminoglycoside antibiotic given IM.
- nephrotoxic and ototoxic.
- obtain baseline audiometric test and repeat every 1-2 months because the
medications impairs the CN VIII.

2009-08-31T20:44:00.000-07:00

DRUGS AFFECTING THE CARDIOVASCULAR SYSTEM

Anticoagulants
Prototype :
- Heparin (SQ and IV)
Warfarin (Orally)
Mechanism of actions :
a. Heparin
- prevents thrombin from converting fibrinogen to fibrin.
b. Warfarin
- suppress coagulation by acting as an
antagonist of vitamin K after 4-5 days.

Hemostasis :

Bleeding/injury
I
Vasoconstriction Plasminogen
I I
Platelet aggregation Plasmin
( temporary plug) I
I I
Clotting factor activation -------------- I
I I I
Intrinsic pathway (8,9,10,11,12) Extrinsic pathway (3,7,10) I
(PTT ) (PT) Vit K dep. I
I I I
I Prothrombin activation I I
I I
Thrombin I
I I
Fibrinogen ------------Fibrin threads ------------- Fibrin split products
(coagulation) ( Removed by liver & spleen )

Indications :
- thrombosis, pulmonary embolism, myocardial infarction
Adverse effect :
- bleeding
Nursing considerations :
1. HEPARIN sodium
- if given SQ don’t aspirate or rub the injection site (above the scapula - best site).
- therapeutic level 1.5-2.5 times normal PTT;
normal PTT is 20-35 sec. = 50-85 sec.
- antidote : (protamine sulfate)

2. WARFARIN sodium (coumadin)
- warfarin is used for long-term .
- onset of action is 4-5 days.
- therapeutic level is 1.5-2.5 times normal PT;
normal PT = 9.6 -11.8 sec. = 25 - 30 sec.
INR = 2 - 3
- should be taken at the same time of the day to maintain at therapeutic level.
- reduce intake of green leafy vegetables.
- antidote : Vitamin K ( Aquamephyton)

Thrombolytics
Prototype :
Streptokinase, Urokinase
Mechanism of actions :
- activates plasminogen to generates plasmin (enzyme that dissolve clots).
Indications :
- use early in the course of MI (within 4-6 hours of the onset)
Nursing considerations :
- monitor bleeding
- antidote : Aminocarpic acid

Antiplatelet Medications
Prototype: aspirin, Dipyridamole (Persantin)
Clopidoigrel (Plavix), Ticlopidine
Mechanism of action :
- inhibit the aggregation of platelet thereby prolonging bleeding time.
Indications :
- used in the prophylaxis of long-term complication following M.I, coronary
revascularization, and thrombotic CVA.
Nursing considerations :
- Monitor bleeding time ( NV = 1-9 mins)
- Take the medication with food.

Cardiac Glycosides
Prototype:
- digoxin (Lanoxin) and digitoxin (Crystodigin)
Mechanism of actions :
- increase intracellular calcium, which causes the heart muscle fibers to contract more
efficiently, producing positive inotropic & negative chronotropic action.
Indications :
- use for CHF, atrial tachycardia and fibrillation
Nursing considerations :
- Monitor for toxicity as evidence by :
nausea, vomiting, anorexia, halo vision, confusion, bradycardia and heart blocks .
- Do not administer if pulse is less than 60 bpm.
- Should be caution in patient with hypothyroidism and hypokalemia.
- Antidote : Digi-bind
- Phenytoin is the drug of choice to manage
digitalis-induced arrhythmia.

Nitrates
Prototype :
- isosorbide dinitrate (Isordil)
- nitroglycerine (Deponit, Nitrostat)
Mechanism of action :
- produce vasodilatation including coronary artery.
Indications :
- angina pectoris, MI, peripheral arterial occlusive disease.
Adverse effects:
- headache, orthostatic hypotension .

Nursing Considerations :
1. Transdermal patch
- apply the patch to a hairless area using a new patch and different site each day.
- remove the patch after 12-24 hours, allowing 10-12 hours “patch free” each day to
prevent tolerance.
2. Sublingual medications :
- note the BP before giving the medication.
- offer sips of water before giving because dryness may inhibit absorption.
- one tablet for pain and repeat every 5 mins. for a total of three doses; if not relieved
after 15 mins., seek medical help.
- stinging or burning sensation indicates that the tablet is fresh.
- instruct patient not to swallow the pill
- sustained release medications should be swallowed and not to be crush.
- protect the pills from light.

Anti-arrhythmic Drugs
Class I (block Na channels)
IA - quinidine, procainamide
IB - lidocaine
IC - flecainamide
Class II (Beta-blockers)
propanolol, esmolol
Class III (block K channels)
amiodarone, bretylium
Class IV (block Ca channels)
verapramil, diltiazem
Nursing considerations :
1. Watch out for signs of CHF.
2. Have client weigh themselves and report
weight gain.
3. Watch out for signs of lidocaine toxicity :
- confusion and restlessness

Antilipemics
Prototype :
a. cholesterol-lowering agents
- cholestyramine, colestipol, lovastatin
b. triglyceride-lowering agents
- gemfibrozil, clofibrate
Mechanism of actions :
- interfere with cholesterol synthesis as well as
decreasing lipoprotein & triglyceride synthesis.
Nursing considerations :
- monitor liver functions while using statins.
- prevent constipation, flatulence, cholelithiasis
- encourage increase fluid and fiber intake.

ANTI – HYPERTENSIVE

Angiotensin-Converting Enzyme (ACE) Inhibitors
Prototype :
captopril (Capoten), enalapril (Vasotec), quinapril, lisinopril
Mechanism of actions :
- prevent peripheral vasoconstriction by blocking conversion of angiotensin I to
angiotensin II decreasing peripheral resistance.
Adverse effect :
- it cause hyperkalemia
- induce chronic cough
Nursing considerations :
- not to discontinue medications because it can cause rebound hypertension.
- avoid using K+ sparing diuretics.

Calcium-Channel Blockers
Prototype :
- Nifedipine (calcibloc, adalat), Amlodipine (norvasc), Felodipine (Plendil)
Verapramil (Isoptin)
Mechanism of action :
- decrease cardiac contractility and the workload of the heart, thus decreasing the
need for O2.
- it also promote vasodilatation of the coronary and peripheral vessels.
Indications :
- hypertension, angina, arrhythmia
Adverse effects :
- bradycardia, hypotension, headache
- reflex tachycardia, constipation
Nursing considerations :
- Administer between meals to enhance absorption.
- Take client’s pulse rate before each dose, withhold if pulse is below 60 bpm.
- Refer for signs of congestive heart failure.

Diuretics
- usually given at morning
CARBONIC ANHYDRASE INHIBITORS
- Acetazolimide (Diamox)
- increase Na+, K+, & HCO3 secretion, along with it is H2O
- metabolic acidosis
OSMOTIC DIURETIC
- Mannitol
- Increase osmotic pressure of the glomerular filtrate.
- hypotension
THIAZIDE DIURETICS
- hydrochlorothiazide
- blocks Na and K reabsorption; reabsorb Ca
- hypercalcemia
LOOP DIURETICS
- Furosemide (Lasix)
- blocks Na, K, and Ca reabsorption
- hypocalcemia
POTASSIUM SPARING DIURETICS
- Spironolactone (Aldactone)
- excrete Na and water but it reabsorb K
- hyperkalemia

2009-08-31T20:41:00.000-07:00

DRUGS USED IN PAIN MANAGEMENT

General Anesthetics
Prototype :
a. Inhalation anesthetics
- enflurane (Ethrane), halothane
- isoflurane (Forane), nitrous oxide
b. Injection anesthetics
- fentanyl (Sublimaze), ketamine (Ketalar),
thiopental Na (Penthotal), etomidate (Amidate)
Mechanism of actions :
- cause CNS depression, by producing loss of consciousness, unresponsiveness to pain
stimuli, and muscle relaxation.
Nursing considerations :
1. Instruct client NPO for 8 hours before administration.
2. Monitor cardio pulmonary depression and hypotension.
3. Monitor urinary retention.
4. Monitor body temperature
- malignant hyperthermic crisis :
dantrolene (antidote)
5. Avoid alcohol or CNS depressants for 24 hours after anesthesia.
6. In patient who received halothane, monitor signs of hepatic fatal side effects :
- rash, fever, nausea, vomiting
- jaundice and altered liver function.

Local and Topical Anesthetic
Prototype :
local : bupivacaine, lidocaine, tetracaine, procaine, mepivacaine, prilocaine
topical : benzocaine, butacaine, dibucaine,lignocaine
Mechanism of action :
- block transmission of impulses across nerve cell membrane.
Adverse effects :
- cardiac dysrhythmias
Nursing considerations :
- lignocaine + prilocaine (EMLA cream) should be applied topically 60 minutes before
procedure.
- administer cautiously to the areas of large broken skin.
- observe for fetal bradycardia in pregnant clients.

Analgesics
Prototype :
a. Narcotic analgesics
- codeine, meperidine (Demerol) morphine, butorphanol (Stadol)
nalbuphine (Nubain)
b. Non – narcotic analgesic
NSAIDs – aspirin (aminosalicylic acid), mefenamic acid (Ponstan),
ibuprofen (Motrin), naproxen, ketoprofen (Orudis), ketorolac.
paracetamol and acetaminophen (Tylenol)
Mechanism of actions :
a. Narcotic analgesics
- alter pain perception by binding to opiod receptors in CNS.
b. Non- narcotic analgesic
- relieves pain and fever by inhibiting the prostaglandin pathway.
Nursing considerations :
1. Monitor respiratory depression & hypotension in clients taking narcotic analgesic.
2. Injury and accident precautions in clients taking narcotic analgesic.
3. Warn clients about possibility of dependency,and do not discontinue narcotics
abruptly in the narcotic-dependent clients.
4. Naloxone is antidote for narcotic overdose.
5. Advice clients to take NSAIDs with food and monitor bleeding complications.
6. Aspirin is contraindicated in clients below 18 years old with flu-like symptoms.
7. Monitor hearing loss in clients taking aspirin.
8. Monitor liver function in clients taking acetaminophen.
9. N-acetylcysteine is antidote for paracetamol overdose.

2009-08-31T20:37:00.000-07:00

Central Nervous System Stimulants

Prototype :
- amphetamines, methylphenidate (Ritalin)
Mechanism of actions :
- increase excitatory CNS neurotransmitter activity and blocks inhibitory impulses.
Indications :
- for obesity (amphetamines)
- attention deficit hyperactivity disorders
- narcolepsy
- drug-induced respiratory depressions.
Adverse effects :
- nervousness, insomnia, restlessness
- hypertension, tachycardia, headache
- anorexia, dry mouth.
Nursing considerations :
1. Should be given at morning.
2. Don’t stop amphetamine abruptly to avoid withdrawal symptoms.
3. Monitor blood pressure and pulse.
4. Ice chips or sugarless gum for dry mouth.
5. Watch out for growth retardation in children taking methylphenidate.

DRUGS AFFECTING MENTAL FUNCTIONING

Sedatives, Hypnotics, and Anxiolytics
Prototype :
a. Benzodiazepines
- diazepam (Valium), lorazipam (Ativan),
alprazolam (Xanax), flurazepam (Dalmane)
b. Barbiturates
- amobarbital, phenobarbital, secobarbital
c. Miscellaneous
- chloral hydrate (Noctec), buspirone (Buspar), paraldehyde (Paral)
Mechanism of actions :
a. Benzodiazepines
- increase the effect of inhibitory neuro transmitter GABA
(gamma-amino butyric acid)
b. Barbiturates and Miscellaneous agents
- depress CNS
Indications :
- induce sleep, sedate and calm clients

Adverse effects :
- hangover-effect, dizziness, CNS depression
- respiratory depression, drug-dependence
Nursing considerations :
1. Warn clients of injuries and falls.
2. Brief period of confusion and excitement upon waking up is common with
benzodiazepines.
3. Warn clients not to discontinue medications abruptly without consulting a physician.
4. Avoid alcohol while taking these drugs.
6. Rotate and don’t shake the ampules of barbiturates. Don’t mix with other drugs.
7. Warn female clients that diazepam is associated with cleft lip.

Antidepressants and Mood Disorder Drugs
Prototype :
a. Tricyclic antidepressants
- amitriptyline (Elavil), protriptyline (Vivactil),
- imipramine (Tofranil), desipramine
b. MAO (monoamine oxidase inhibitors )
- isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Pernate)
c. Second-generation antidepressants
- fluoxetine (Prozac), trazodone (Desyrel)
d. Lithium
Mechanism of actions :
a. Tricyclic antidepressants
- increase receptor sensitivity to serotonin and/or norepinephrine.
b. MAO inhibitors
- inhibit the enzyme MAO that metabolize the neurotransmitters norepinephrine and
serotonin.
c. Second – generation antidepressants
- inhibits the reuptake of serotonin.
d. Lithium
- increase serotonin & norepinephrine uptake
Adverse effects :
- dry mouth, blurred vision, urine retention, constipation (anticholinergic effects)
- orthostatic hypotension, insomnia
- hypertensive crisis (MAO)
- dehydration (Lithium).
Nursing considerations :
1. Caution client to rise slowly to reduce the effects of orthostatic hypotension.
2. Take antidepressant with food to enhance absorption
3. Explain to client that full response may take several weeks (2 weeks).
4. Assess client for constipation resulting from tricyclic antidepressant use.

5. Client taking MAO inhibitors should avoid tyramine-rich foods to avoid
hypertensive crisis.
- aged cheese, sour cream, yogurt, beer, wine, chocolate, soy sauce and yeast
- pentholamine (Regintine) is the drug of choice for hypertensive crisis.
6. Inform physician and withhold fluoxetine if client develop rashes.
7. Take lithium with food to reduce GI effects
- > 1.5 mEq/L blood level may cause toxicity manifested by:
confusion, lethargy, seizures,hyperreflexia.
- maintain salt and adequate fluid intake
- tremors may occur but it is temporary
- monitor white blood cell count (increase).

Antipsychotic drugs (Neuroleptics)
Prototype :
a. Phenothiazines
- chlorpromazine (Thorazine),
- trifluoperazine (Stelazine),
- thioridazine (Mellaril)
b. Other Agents
- clozapine (Clozaril), haloperidol (Haldol)
Mechanism of action :
- block dopamine receptor in the limbic system, hypothalamus, and
other regions of the brain.
Adverse effects :
- Extra pyramidal symptoms such as dystonia, pseudoparkinsonism, and
an irreversible tardive dyskinesia as manifested by :
a. lip smacking
b. fine wormlike tongue movement
c. involuntary movements of arms and leg.
- Neuroleptic malignant syndrome
a. fever, tachycardia, tachypnea, diaphoresis, cardiovascular collapse
b. muscle rigidity, seizures.
- orthostatic hypotension
Nursing considerations :
1. Teach family members the signs of EPS and NMS, and report to physician
immediately.
2. Normalization of symptoms may not occur for several weeks after beginning of
therapy .
3. Avoid administering haloperidol intravenously
4. Watch out of neutropenia with clozapine.
5. Watch out for orthostatic hypotension and photosensitivity with phenothiazine.
6. Be sure that oral doses are swallowed, and not hoarded.

2009-08-31T20:34:00.000-07:00

Skeletal Muscle Relaxants Agents

Prototype :
- methacarbamol (Robaxin), baclofen (Lioresal), dantrolene (Dantrium),
metaxalone (Skelaxin), orphanedrine (Norgesic), chlorzoxazone
Mechanism of actions:
- depress CNS
- inhibit calcium ion release in the muscle
- enhance the inhibitory action of GABA (gamma-amino butyric acid)
Indications :
- for acute musculoskeletal pain
- for muscle spasticity associated with multiple sclerosis, cerebral palsy, CVA, and
spinal cord injury.
Adverse effects :
- hypotonia, ataxia, hypotension, drowsiness
- blurred vision, bradycardia, depression, urine retention
Nursing considerations :
1. Caution clients that mental alertness may be impaired.
2. Monitor neuromuscular status, bowel and bladder functions.
3. Inform clients that maximum benefit of baclofen is attained for 1-2 months.
4. Reduce baclofen dosage gradually because of associated withdrawal symptoms :
Confusion, hallucinations, paranoia & rebound spasticity.

Anticonvulsants
Prototype :
a. Hydantoins - phenytoin (Dilantin)
b. Barbiturates - phenobarbital ( Luminal)
c. Miscellaneous
- carbamazepine (Tegretol), diazepam, clorazepate (Tranxene),
valproic acid (Dapakene), ethosuximide (Zarontin).
Mechanism of action :
- treat seizures by depressing abnormal neuronal activity in motor cortex.

Adverse effects :
- sedation & drowsiness, gingival hyperplasia
- diplopia, nystagmus, vertigo, dizziness
- thrombocytopenia, aplastic anemia
Nursing considerations :
1. Advise female clients to use contraceptives.
2. Inform clients taking phenytoin that harmless urine discoloration is common.
3. Warn clients with diabetes that hydantoins may increase blood sugar level and that
valproic acid may produce a false positive result in urine ketone test.
4. Teach clients receiving carbamazepine to identify symptoms of bone marrow
depressions.
5. Reassure that barbiturates are not addictive at a low dosage.
6. Avoid taking alcohol with barbiturates.
7. Administer IV phenytoin slowly to avoid cardiotoxicity.
8. Avoid mixing other drugs in same syringe with phenytoin.

Antiparkinsonian Agents
Prototype :
a. Anticholinergic agents
- trihexyphenidyl (Artane), benztropine (Congentin)
b. Dopaminergic agents
- Levodopa, carbidopa-levodopa (Sinemet), amantidine (Symmetrel),
pergolide (Permax), selegiline (Eldepryl), bromocriptine.
Mechanism of actions :
a. anticholinergic agents
- inhibit cerebral motor centers.
b. dopaminergic agents
- increasing dopamine concentrations or
enhancing neurotransmitter functioning.
Adverse effects of dopaminergic agents:
a. levodopa – nausea, vomiting, anorexia, orthostatic hypotension,
dark-colored urine and sweat
b. amantidine – ankle edema, constipation
c. bromocriptine – palpitations, tachycardia
Nursing considerations :
1. Give dopaminergic agents after meals to reduce GI symptoms.
2. Reassure client that levodopa may cause harmless darkening of urine and sweat.
3. Avoid taking Vit B6 (pyridoxine) with levodopa because it speed up metabolism.
4. Educate clients to minimize orthostatic hypotension.
5. Elevate leg to reduce ankle edema.

2009-08-31T20:29:00.000-07:00

CLASSIFICATIONS Of DRUGS

DRUGS AFFECTING THE CENTRAL AND AUTONOMIC SYSTEM

Cholinergic Agents (Parasympathomemitics)
Prototype :
- synthetic acetylcholine, pilocarpine, carbachol, bethanecol (Urocholine),
edrophonium (Tensilon), neostigmine (Prostigmine), pyridostigmine (Mestinon).
Mechanism of action :
- stimulates cholinergic receptors by mimicking acetylcholine or inhibition of
enzyme cholinesterase.
Indications :
- glaucoma, urine retention, Myasthenia Gravis
- antidote to neuromuscular blocking agents : tricyclic antidepressants and atropine
Adverse effects :
- blurring of vision, miosis
- increase in salivation, intestinal cramps
- bronchoconstriction, wheezing, DOB
- hypotension and bradycardia
Nursing considerations :
1. Warn & monitor clients of the side effects.
2. Have atropine available for use as antidote.

Cholinergic Blocking Agents (Parasympatholytics, Anticholinergics)
Prototype :
- atropine, scopalamine (Triptone), dicyclomine (Bentyl),
propantheline (Pro-Banthine).
Mechanism of actions :
- block the binding of acetylcholine in the receptors of parasympathetic nerves.
Indications :
- use preoperatively to dry up secretions.
- treat spasticity of GI or urinary tract.
- use for treatment of bradycardia, asthma, parkinsonism.
- use for antidote in organophosphate poisoning.
Adverse effects :
- dry mouth , dilatation of pupils, tachycardia
- urinary retention, ileus, heat stroke
Nursing considerations :
1. Keep client’s in cool environment.
2. Watch out for signs of heatstroke and dehydration.
3. Encourage clients to increase fluid intake and use of sugarless gum/candy for dry
mouth.
4. For GI spasticity, administer 30 minutes before meals and at bed time.

Adrenergic Agents (Sympathomimetics)
Prototype :
- epinephrine, norepinephrine, ephedrine, dopamine, dobutamine, phenylephrine,
terbutaline, albuterol, isoproterenol.
Mechanism of actions :
- stimulate alpha and beta adrenergic receptor directly or trigger the release of
catecholamines indirectly causing sympathetic effects.
Indications :
- cardiopulmonary arrest, hypotension
- COPD and asthma, nasal congestions
- allergic reaction, anaphylactic shock
Adverse effects :
- restlessness, insomnia, tremors, nausea
- palpitations, angina, tachycardia, HPN
Nursing considerations :
1. Contraindicated in clients w/ hyperthyroidism,
pheochromocytoma & cardiovascular disease.
2. Monitor vital signs and advice precautions.
3. Should be taken with food.

Adrenergic Blocking Agents
Prototype :
a. Alpha blockers
- phentolamine (Regintine), phenoxybenzamine, prazosin (Minipress),
reserpine (Serpasil), terazosin (Hytrin)
- clonidine (Catapress), methyldopa (Aldomet)
b. Beta blockers
- atenolol (Tenormin), esmolol (Brevibloc),
metoprolol (Lopressor), nadolol (Corgard),
propanolol (Inderal), timolol ( Blocadren)
Mechanism of actions :
a. alpha blockers
- inhibits action of a-receptors in vascular smooth muscle to cause vasodilatation.
b. beta blockers
- compete with epinephrine in b-receptors in heart, pulmonary airways, peripheral
circulation and CNS.
Indications :
- Raynaud’s disease, hypertension, pheochromocytoma.
- angina, arrhythmias, mitral valve prolapse, glaucoma
Adverse effects :
- orthostatic hypotension, bradycardia, CHF

- depression, insomnia and vertigo
- bronchospasm and dyspnea, nasal stuffiness, cold extremities

Nursing considerations :
1. Administer oral alpha-blockers with milk to minimize GI side effects.
2. Administer oral beta-blockers before meals and at a.m. if insomnia occurs.
3. Check client’s apical pulse rate before drug administration, refer if below 60 bpm.
4. Hypotensive precautions.
5. Warn clients not to drive or operate dangerous machinery until he/she has
adjusted to medications

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Fundamentals of Pharmacology

1. Pharmacokinetics
- study of drug’s changes as it enters and passes through the body.
a. absorption
b. distribution
c. biotransformation
d. excretion

2. Pharmacodynamics
- mechanism by which drugs produce changes in body tissue.
a. desired effect - intended action of drugs
b. adverse effect - harmful unintended reactions
c. side effects – consequence reactions
d. toxicity – the degree which something is poisonous
digoxin = 0.5 – 2.0 ng/mL
lithium = 0.5 – 1.5 mEq/L

Safety and Efficacy
Nursing Principles :
1. Always verify the Five Rights .
a. the right medications
b. the right client
c. the right dosage
d. the right form, route and technique
e. the right time
2. Chart drug administration only after its been given, never before.
3. Never leave the medication on cart or tray unattended.
4. Chart observed therapeutic and adverse effects accurately and fully.
5. Check history for allergies and potential drug interactions before administering a
newly ordered drug.
6. Inform the prescribing physician of any observed adverse effects; if cannot be
located, inform the nursing supervisor
7. Question drug orders that are unclear, that appear to contain errors, or that have
potential to harm.
8. Take the following actions if an error occurs :
a. immediately notify the nursing supervisor, the prescribing physician, and the
pharmacist.
b. assess the client’s condition and provide any necessary care.
9. For postpartum women, advice to take drugs after breastfeeding.
Administration of Drugs :

Routes and Nursing considerations:
1. Enteral – oral, sublingual, rectal, gastric tubes
- capsulated pill, sustained release and enteric coated should not be crushed.
2. Parenteral – IV, IM, SQ, ID, IT, IA, epidural.
- vastus lateralis (safest site for IM)
3. Topical – skin, inhalants, mucus membrane.

Eye medications :
- administer eyedrops first then ointment.
- use a separate bottle for each client.
- instruct the client to tilt the head backward, open eyes and look up.
- avoid contact of medication bottle to the eyeball.
- place prescribed dose in the lower conjunctival sac.
- instruct the client to press the inner canthus for 30-60 seconds.
- instruct the client to close the eye gently.

Ear drops
- in infant and children younger than 3 y.o, pull pinna downward and backward.
- in older children and adult, upward and backward.
- direct the solution on the wall of the ear canal, not directly on the ear drum

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Drug – chemical introduced into the body to cause some changes
• WHO def: any product/subs used to modify/explore physiologic system/pathologic states for the benefit of the patient
Pharmacology – study of the manner in which the function of living system is
affected by chemical agents/drugs
• Science concerned with history, sources, physical & chemical properties of drugs & the way in which drug affects living system

Subdivisions of pharmacology:

1. pharmacodynamics – study of the biochemical & physiological effects of drugs & mechanisms of action
• what the drug does to the body
2. pharmacokinetics – deals with the absorption, distribution, biotransformation & excretion of drugs
• what the body does to the drug
3. pharmacotherapeutics – study of drugs used in the diagnosis, prevention, suppression, & treatment of diseases
• deals with beneficial effects of the drugs (medicines)
4. pharmacognosy – study of drugs in their original unaltered state; origin of drugs
• source of drugs
• ex: penicillin from penicillium (fungi)
5. Toxicology – study of biologic toxins: study of poison & its effects deals with deleterious effects of physical & chemical agents (including drugs) in human

Pharmacoeconomics – study of relationship of drugs & economics

Pharmacovigilance – science of collecting,researching, analyzing, & evaluating set of information about adverse drug effects.
Receptor – a component of the cell that interacts with drug, initiating a chain of biochemical events leading to drugs’ observed effects
• Human body works through complicated series of chemical reactions & processes
• Important aspects of nursing: understanding how drug ant on body to cause changes & apply that knowledge in clinical setting
Patients take complicated drug regimen & receive potentially toxic drug
Some manage their own care at home
• Nursing responsibilities regarding drug therapy:
Administering drugs
Assessing drug effects
Intervening to make drug regimen more tolerable
Provide patient teachings about drugs & drug regimen
• Knowing how drug works --- easier to handle --- enhances drug therapy

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INTRODUCTION TO PHARMACOLOGY

1. HISTORY
• Early drug – plants, animals & minerals
• 2700 BB – earliest recorded drug use found in Middle East & China
• 1550 BC – Egyptians created Ebers Medical Papyrus
Castor oil – laxative
Opium – pain
Moldy bread – wounds & bruises
• Galen (131-201 AD) Roman physician; initiated common use of prescriptions
• 1240 AD – introduction of apothecary system (Arab doctors)
1st set of drug standards & measurements (grains, drams, minims), currently being phased out
• 15th century – apothecary shops owned by barber, surgeons, physicians, independent merchants
• 18th century – small pox vaccine (by Jenner)
Digitalis from foxglove plant for strengthening & slowing of heartbeat Vitamin C from fruits
• 19th century – morphine & codeine extract from opium
Introduction of atropine & iodine
Amyl nitrite used to relieve anginal pain
Discovery of anesthetics (ether, nitrous oxide)
• Early 20th century – aspirin from salicylic acid
Introduction of Phenobarbital, insulin, sulforamides
• Mid 20th century
1940 – Discovery antibiotics (penicilline, tetracycline, streptomycin), antihistamines, cortisone
1950 – discovery antipsychotic drug, antihypertensives, oral contraceptives, polio vaccine