Pharmacology Review (Dilantin)

1 PHARMACOLOGY HESI REVIEW DRUGS AFFECTING THE NERVOUS SYSTEM ANTICONVULSANTS/ANTISEIZURE MEDICATIONS Prototype : a. Hydantoins - phenytoin (Dilantin) b. Barbiturates - phenobarbital ( Luminal) 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. 4. Reassure that barbiturates are not addictive at a low dosage. 5. Avoid taking alcohol with barbiturates. 6. Administer IV phenytoin slowly to avoid cardiotoxicity. 7. 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) Adverse effects of dopaminergic agents: a. levodopa–nausea, vomiting, anorexia, orthostatic hypotension, dark-colored urine and sweat b. amantidine – ankle edema, constipation 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) because it reverses effects of levodopa. 4. Change positions slowly to avoid orthostatic hypotension. 5. Elevate leg to reduce ankle edema. DRUGS AFFECTING MENTAL FUNCTIONING SEDATIVES, HYPNOTICS, AND ANXIOLYTICS – induce sleep, sedate & calm clients Prototype: a. Benzodiazepines (end with –epam) - diazepam (Valium), lorazepam (Ativan), alprazolam (Xanax), flurazepam (Dalmane) b. Barbiturates - phenobarbital, Adverse effects: - hangover-effect, dizziness, CNS depression - respiratory depression, drug-dependence 2 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 ampoules 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), imipramine (Tofranil), desipramine b. MAOI (monoamine oxidase inhibitors) -phenelzine (Nardil), tranylcypromine (Pernate) c. Second-generation antidepressants - fluoxetine (Prozac) Adverse effects: - dry mouth, blurred vision, urine retention, constipation (anticholinergic effects) - orthostatic hypotension, insomnia - hypertensive crisis (MAO) 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 6. Inform physician and withhold fluoxetine if client develop rashes. ANTIPSYCHOTIC DRUGS (Neuroleptics) Prototype: a. Phenothiazines - chlorpromazine (Thorazine), - thioridazine (Mellaril) b. Other Agents – olanzapine (Zyprexa) , haloperidol (Haldol) Mechanism of action: - block dopamine receptors in the limbic system, hypothalamus, and other regions of the brain. Adverse effects: - Extra pyramidal syndrome (or EPS) 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 (NMS) 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. Watch out for orthostatic hypotension and photosensitivity with phenothiazine. 6. Be sure that oral doses are swallowed, and not hoarded. 3 DRUGS USED IN PAIN MANAGEMENT ANALGESICS Prototype: a. Narcotic analgesics - codeine, meperidine (Demerol), morphine b. Non – narcotic analgesics NSAIDs – aspirin (acetylsalicylic acid), ibuprofen (Motrin) paracetamol and acetaminophen (Tylenol) Mechanism of actions: a. Narcotic analgesics - alter pain perception by binding to opioid receptors in CNS. b. Non- narcotic analgesics - relieve pain and fever by inhibiting the prostaglandin pathway. Nursing considerations: 1. Monitor respiratory depression & hypotension in clients taking narcotic analgesics. 2. Injury and accident precautions in clients taking narcotic analgesic. 3. Warn clients about possibility of dependency, and do not discontinue narcotics abruptly in narcotic-dependent clients. 4. Naloxone is the antidote for narcotic overdose. 5. Advice clients to take NSAIDs with food and monitor for bleeding complications. 6. Aspirin is contraindicated in clients below 18 years old with flu-like symptoms. 7. Monitor hearing loss in clients taking aspirin. 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. Indications: - thrombosis, pulmonary embolism, myocardial infarction Adverse effect: - bleeding Nursing considerations: 1. HEPARIN sodium - test : PTT - antidote : (protamine sulfate) 2. WARFARIN sodium (coumadin) - test : INR - reduce intake of green leafy vegetables. - antidote : Vitamin K ( Aquamephyton) ANTIPLATELET MEDICATIONS Prototype: aspirin (ASA), Dipyridamole (Persantin), Clopidogrel (Plavix) 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 & thrombotic CVA 4 Nursing considerations: - Monitor bleeding time ( NV = 1-9 mins) - Take the medication with food. CARDIAC GLYCOSIDES Prototype: digoxin (Lanoxin) 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 evidenced by: o 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 : Digoxin Immune FAB 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, 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 10 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 crushed - protect the pills from light ANTI – HYPERTENSIVES ANGIOTENSIN-CONVERTING ENZYME (ACE) INHIBITORS (DRUG NAMES END IN WITH “-PRIL”) 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 : 5 - hyperkalemia - induce chronic dry cough Nursing considerations : - not to discontinue medications because it can cause rebound hypertension. - avoid using K+ sparing diuretics. ADRENERGIC BLOCKING AGENTS Prototype: Beta blockers (drug names end with “-olol”) - atenolol (Tenormin), metoprolol (Lopressor), propanolol (Inderal), timolol ( Blocadren) Mechanism of actions : - 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 beta-blockers before meals and at a.m. if insomnia occurs. 2. Check client’s apical pulse rate before drug administration, refer if below 60 bpm. 3. Change positions slowly to avoid orthostatic hypotension. 4. Warn clients not to drive or operate dangerous machinery until he/she has adjusted to medications. CALCIUM-CHANNEL BLOCKERS Prototype : - Nifedipine (calcibloc, adalat), Amlodipine (norvasc), Verapramil (Isoptin) Mechanism of action: - decrease cardiac contractility and the workload of the heart, thus decreasing the need for O 2 - it also promotes 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 Thiazides - hydrochlorothiazide - blocks Na and K reabsorption; reabsorb Ca - hypercalcemia Loop diuretics - furosemide (Lasix) - blocks Na, K, and Ca reabsorption - hypocalcemia 6 Potassium sparing diuretics - Spironolactone (Aldactone) - excrete Na and water but it reabsorbs K - hyperkalemia RESPIRATORY MEDICATIONS BRONCHODILATORS Prototype : Symphatomimetic Xanthines - albuterol, salbutamol - aminophylline - isoproterenol, salmeterol - theophylline - terbutaline Mechanism of actions: - sympathomimetic (-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 in hyperthyroidism, cardiac dysrhythmia, or uncontrolled seizure disorder. - Should be used with caution in patients with HPN and narrow-angle glaucoma. GLUCOCORTICOIDS (Corticosteroids) Prototype: - prednisone 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 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 NSAIDs while taking steroids. - Take inhaled bronchodilators first before taking inhaled steroids, and rinse mouth after using. ANTI-HISTAMINES (H-1 blockers) Prototype: - Loratidine (Claritin) - Brompheniramine (Dimetapp) - Diphenhydramine (Benadryl) 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. 7 Nursing Considerations : - Administer with food and drink. - Precautions in handling machinery and driving while taking these drugs. - Ice chips or candy for dry mouth DECONGESTANTS - pseudoephedrine (Sudafed) – adrenergic (sympathomimetic) agent Caution : do not use with clients with HPN DRUGS AFFECTING GASTROINTESTINAL SYSTEM ANTI-ULCER DRUGS 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 (END WITH –IDINE) 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 develop with chronic use of cimetidine. PROTON – PUMP INHIBITORS (PPI) (END WITH –AZOLE) 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). 8 Mechanism of action: - coats the mucosa to prevent ulcerations. Nursing consideration: - Given before meals. - Misoprostol is contraindicated for pregnants. - Sucralfate cause constipation. ANTII-EMETICS (ANTI-VOMITING) - Dimenhydrinate (Gravol) – an anticholinergic; used also for motion sickness Diphenhydramine (Benadryl) – an antihistamie Metoclopramide (Reglan) – dopamine antagonist o Not available in Canada; EPS side effects 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. Osmotic : lactulose (Duphalac), Na biphosphate (Fleet enema) & magnesium salt (Milk of Magnesia) - retain fluid and distend intestine b. Fecal softeners : ducosate (Dialose) - emulsify fecal fat and water c. Stimulant : bisacodyl (Dulcolax) & senna (X-prep) - irritates intestinal mucosa and stimulates intestinal smooth muscles d. bulk-forming laxative (Metamucil) - increase fecal bulk and water content e. Emollient/Lubricant : mineral oil - lubricates & prevent colon absorption DRUGS AFFECTING THE ENDOCRINE SYSTEM THYROID AGENTS Prototype:  Synthroid (levothyroxine) Mechanism of action: - function as natural or synthetic hormones. Nursing considerations: - Taken in the morning. - Caution with coronary artery disease. - Monitor for signs of hyperthyroidism and refer for decreasing the dose. ANTIDIABETICS ORAL HYPOGLYCEMIC AGENTS (OHA) 1. Sulfonylureas 9    stimulate insulin secretions and increase tissue sensitivity to insulin. First Generation: Chlorpropamide (Diabenase) - disulfiram precautions Second Generation: Glypizide, Glymepiride 2. Biguanides  facilitates insulin action on the peripheral receptor site  Metformin and Glucophage (Glucovance) - side effect is lactic acidosis 3. Alpha-glucosidase inhibitors  delay carbohydrate absorption in the intestinal system  Acarbose (Precose) – side effect is diarrhea 4. Thiazolinidine  increase tissue sensitivity of insulin; e.g Rosiglitazone (Avandia) – already discontinued Nursing considerations: - Effective only for type II DM - Contraindicated to pregnant & breastfeeding. - Given before meals - Monitor for signs of hypoglycemia. Insulin Type of Insulin & Brand Names Rapid-Acting Humalog or lispro Novolog or aspart Apidra or glulisine Onset Peak 15-30 min. 30-90 min 3-5 hours 10-20 min. 40-50 min. 3-5 hours 20-30 min. 30-90 min. 1-2½ hours 2-5 hours 5-8 hours 2-3 hours 2-3 hours 4-12 hours 18-24 hours 3-10 hours 18-24 hours Short-Acting Regular (R) humulin or 30 min. -1 hour novolin Velosulin (for use in the 30 min.-1 hour insulin pump) Intermediate-Acting NPH (N) 1-2 hours Lente (L) 1-2½ hours Duration Role in Blood Sugar Management Rapid-acting insulin covers insulin needs for meals eaten at the same time as the injection. This type of insulin is used with longer-acting insulin. Short-acting insulin covers insulin needs for meals eaten within 30-60 minutes Intermediate-acting insulin covers insulin needs for about half the day or overnight. This type of insulin is often combined with rapid- or short-acting insulin. 10 Long-Acting 30 min.-3 hours 10-20 hours 20-36 hours Lantus (Glargine) 1-1½ hour No peak time; insulin is delivered at a steady level 20-24 hours Levemir or detemir 1-2 hours 6-8 hours Up to 24 hours Ultralente (U) Long-acting insulin covers insulin needs for about one full day. This type of insulin is often combined, when needed, with rapid- or short-acting insulin. * Cannot mix these with other insulins in the same vial. Have to give two separate injections. Pre-Mixed* Humulin 70/30 30 min. 2-4 hours 14-24 hours These products are Novolin 70/30 30 min. 2-12 hours Up to 24 hours generally taken twice Novolog 70/30 10-20 min. 1-4 hours Up to 24 hours a day before mealtime. Humulin 50/50 30 min. 2-5 hours 18-24 hours Humalog mix 30 min.-2½ 15 min. 16-20 hours 75/25 hours *Premixed insulins are a combination of specific proportions of intermediate-acting and shortacting insulin in one bottle or insulin pen (the numbers following the brand name indicate the percentage of each type of insulin). Nursing considerations: - Usually given before meals. - Roll the bottle in palm of hands, don’t shake. - Inject amount of air that is equal to each dose into the bottle- short acting last (clear). - Aspirate short acting first, then long or intermediate (cloudy). - Alcohol is recommended for cleansing bottle but not with skin. - Pinch skin, avoid I.M, don’t aspirate. - Rotate the injection site an inch a part. - Prefilled syringes are stored vertically, needle-up. - May increase dose during illnesses. - Used bottles stored in room temperature, unused bottle stored in refrigerator. - Monitor for acute hypoglycemia; treat with: a. 3-4 commercially prepared glucose tablet b. 4-6 ounce of fruit juice or regular soda c. 2-3 teaspoons of honey d. Glucagon 1 gm SQ or IM e. D50-50 IV. DRUGS FOR TREATING INFECTION ANTIBACTERIAL AGENTS 1. Cell wall inhibitors a. penicillins - pen G, amoxicillin, cloxacillin b. cephalosphorins - cephalexin, cefaclor c. glycopeptide – vancomycin 2. Protein synthesis inhibitors a. aminoglycosides - amikacin, gentamycin b. macrolide – erythromycin 11 c. tetracycline’s 3. Antimetabolites - blocks folic acid synthesis a. Sulfonamides – cotrimoxazole 4. DNA synthesis inhibitors a. quinolones - ciprofloxacin, norfloxacin b. metronidazole (Flagyl) Adverse effects : 1. Aminoglycoside - nephrotoxicity & ototoxicity 2. Sulfonamides - Steven-Johnson’s syndrome, photosensitivity Quinolones - insomnia 3. Tetracyclines - bone problems 4. Erythromycin - hepatitis Nursing considerations: 1. Collect appropriate specimen for C & S before starting antibiotics. 2. Check client’s history of allergies. 3. Monitor adverse effects: ALL antibiotics can cause nausea, vomiting & diarrhea DRUGS with MULTIPLE USES CHOLINERGIC BLOCKING AGENTS (Parasympatholytics, Anticholinergics) Prototype: atropine 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 (insecticide) Adverse effects: - dry mouth , dilatation of pupils, tachycardia - urinary retention, ileus, heat stroke Nursing considerations: 1. Keep clients 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 bedtime. ADRENERGIC AGENTS (Sympathomimetics) Prototype: - epinephrine, 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 12 Nursing considerations: 1. Contraindicated in clients w/ hyperthyroidism, pheochromocytoma & cardiovascular disease. 2. Monitor vital signs and advice precautions MISCELLANEOUS DRUGS ANTI-GOUT - Acute attacks : phenylbutazone (an NSAID), colchicine Maintenance : allopurinol 13 *These lists are not extensive but should help Drugs and their Antidotes 1. 2. 3. 4. 5. 6. 7. 8. Digoxin – Digibind Heparin/Lovenox - Protamine Sulfate Morphine sulfate - Naloxone Hydrochloride Warfarin/Coumadin- Vitamin K Acetaminophen - Acetylcycteine Benzodiazepine - Flumazenil Penicillin – Epinephrine Anticholinergic poisoning - Physostigmine Drug Classification (Drugs “Endings” and their Classification) -caine Local Anesthetics -dine H2 Blockers (Anti-Ulcers) -ide Oral Hypoglycemics -micin Antibiotics -mide Diuretics -zide Diuretics -olol Beta Blockers -pam Anti-Anxiety Agents -sone Steroids -vir Antivirals -cillin Antibiotics -done Opioid Analgesics -lam Anti-Anxiety Agents -mycin Antibiotics -nium Neuromuscular Blocking Agents -oxacin Antibiotics -pril ACE Inhibitors -statin Anti-hyperlipidemics