Medication Tutorial
 

Module Description 

This module is designed as a tutorial to assist nursing students with preparation for the National Council Licensure Examination for Registered Nurses (NCLEX-RN) Computer Adaptive Testing (CAT). Students will review pertinent information related to medications that require therapeutic drug monitoring. 

After completing this module, the learner will be able to: 

1. Identify the medications that require therapeutic drug monitoring to manage drug therapy for clients. 
2. List the therapeutic levels for selected medications that require therapeutic drug monitoring.
3. Identify the side effects of toxic levels for selected medications that require therapeutic drug monitoring. 

Online Tutorial 

According to Fischback (A Manual of Laboratory and Diagnostic Tests), therapeutic drug monitoring is a reliable approach to managing drug therapy for clients. Monitoring drug therapy is especially important when the potential for drug toxicity is significant and can lead to serious complications or when inadequate levels of drugs can lead to ineffective therapy. 

Some drugs like Digoxin require routine monitoring and others like Antibiotics require monitoring in certain situations. The plasma level of drugs needed to control symptoms is called the STEADY-STATE CONCENTRATION, and is usually maintained by a combination of drug dosage and dosage interval. When drugs are monitored at intervals, this lessens the chance of developing complications related to the side effects associated with toxicity. 

Drug	Therapeutic and Toxic Levels
Acetaminophen (Tylenol)	Therapeutic: 1-30 mcg/ml Toxic: >200 mcg/ml Contraindicated in: Liver disease Side Effects of Toxicity: Hepatic Necrosis
Alcohol (Ethanol)	Therapeutic Level: 100 mcg/ml Toxic: >400 mcg/ml
Amitriptyline (Elavil)	Therapeutic: 120-250 mcg/ml Toxic: >500 mcg/ml Contraindicated in: Narrow-angle glaucoma and potential fatal reactions when used with MAO inhibitors Side Effects of Toxicity: Drowsiness, sedation, lethary, fatigue, dry mouth and eyes, blurred vision, hypotension, and tachycardia.  Caution patients to use a sun screen. Therapeutic effects within 2 to 6 weeks of initiating therapy.
Carbamazepine (Tegretol)	Therapeutic: 8-12 mcg/ml Toxic: >15 mcg/ml Contraindicated in: Bone marrow depression Side Effects of Toxicity: Drowsiness, dizziness, and ataxia. Caution patients to use a sun screen and to carry a medical alert card.
Chlordiazepoxide (Librium)	Therapeutic: 700-1000 mcg/ml Toxic: >5000 mcg/ml Contraindicated in:  Comatose patients with CNS depression, narrow-angle glaucoma Side Effects of Toxicity: Drowsiness and dizziness. Alcohol Withdrawal Treatment: Assess patients for signs and symptoms of delirium tremors (DTs).
Desopyramide (Norpace)	Therapeutic: Variable Toxic: >7 mcg/ml Contraindicated in:  Cardiogenic shock, 2nd and 3rd degree heart blocks, sick sinus syndrome Side Effects of Toxicity: Signs and symptoms of congestive heart failure.
Diazepam (Valium)	Therapeutic: 100-1000 mcg/ml Toxic: >5000 mcg/ml Contraindicated in:  Comatose patients with CNS depression, narrow-angle glaucoma Side Effects of Toxicity: Sedation with ataxia, dizziness, and slurred speech. Therapeutic effects within 1 to 2 weeks of initiating therapy.
Digitoxin	Therapeutic: 20-35 ng/ml Toxic: >45 ng/ml Contraindicated in:  Uncontrolled ventricular arrhythmias, AV block Side Effects of Toxicity: Abdominal pain, anorexia, nausea, vomiting, visual disturbances, bradycardia, and other arrhythmias.
Digoxin	Therapeutic: 0.8-1.5 mcg/ml Toxic: >2 mcg/ml Contraindicated in:  Uncontrolled ventricular arrhythmias, AV block Side Effects of Toxicity: Abdominal pain, anorexia, nausea, vomiting, visual disturbances, bradycardia, and other arrhythmias.
Doxepin	Therapeutic: 30-150 mcg/ml Toxic: >500 mcg/ml Contraindicated in:  Narrow-angle glaucoma Side Effects of Toxicity: Sedation, fatigue, blurred vision, hypotension, dry mouth, and constipation. Caution patients to use a sun screen. May cause hypotension, tachycardia, and potentially fatal reactions when used with MAO inhibitors Therapeutic effects within 2 to 6 weeks of initiating therapy.
Glucocorticoids	Contraindicated in:  Serious infections Signs of adrenal insufficiency: Hypotension, weight loss, weakness, nausea, vomiting, anorexia, lethargy, confusion, restlessness. Side Effects:  Depression or euphoria, personality changes, hypertension, decreased wound healing, petechiae, ecchymoses, hyperglycemia, hypokalemia, hypernatremia, fluid retention, aseptic necrosis of joints, osteoporosis, cushingoid appearance (moon face, and buffalo hump) Monitor blood sugars, BUN, creatinine. Advise patients that medication should NOT be abruptly discontinued by tapered off over 2 to 4 weeks.
Imipramine (Tofranil)	Therapeutic: 125-250 mcg/ml Toxic: >500 mcg/ml Contraindicated in:  Narrow-angle glaucoma Side Effects of Toxicity: Disturbed concentration, confusion, restlessness, agitation, convulsions, drowsiness, mydriasis, arrhythmias, fever, hallucinations, vomiting, and dyspnea.  Caution patients to use a sun screen. Therapeutic effects within 2 to 6 weeks of initiating therapy.
Lithium	Therapeutic: 0.6-1.2 mcg/ml Toxic: >2 mcg/ml Serum levels should be monitored twice weekly during initiation of therapy and every 2 to 3 months durgin chronic therapy.  Contraindicated in:  Severe cardiovascular or renal disease, dehydrated or debilitated patients Side Effects of Toxicity: Vomiting, diarrhea, slurred speech, decreased coordination, drowsiness, muscle weakness, and twitching. Therapeutic effects within 1 to 3 weeks of initiating therapy.
Lidocaine (Xylocaine)	Therapeutic: 1.5-6 mcg/ml Toxic: >6-8 mcg/ml Contraindicated in:  Advanced AV block Side Effects of Toxicity: Confusion, excitation, blurred or double vision, nausea, vomiting, ringing in ears, tremors, twitching, convulsion, difficulty breathing, severe dizziness or fainting, and slow heart rate.
Magnesium sulfate	Contraindicated in:  Hypermagnesemia, hypocalcemia, anuria, and heart block Side Effects of Toxicity: Decreased respiratory rate, bradycardia, arrhythmias, hypotension, drowsiness, flushing, sweating, and hypothermia. Monitor neurologic status before and throughout therapy. Institute seizure precautions.
Methotrexate	Therapeutic: Variable Toxic: >454 mcg/ml (48 hours after high dose) Contraindicated in:  Pregnancy and lactation (teratogenic effects) Side Effects of Toxicity: Hyperuricemia, abdominal pain, diarrhea, stomatitis, hepatotoxicity, pulcomary toxicity, nephrotoxicity, anemia, leukopenia, thrombocytopenia, and folic acid deficiency Caution patients to use a sun screen. Rescue Drug to Prevent Fatal Toxicity: Leucovorin (folinic acid)
Phenobarbital	Therapeutic: 15-40 mcg/ml Toxic: Varies 35-80 mcg/ml Contraindicated in:  Comatose patients with CNS depression Side Effects of Toxicity: Confusion, drowsiness, dyspnea, slurred speech, and staggering.
Phenytoin (Dilantin)	Therapeutic: 10-20 mcg/ml Toxic: Varies with symptoms Contraindicated in: Sinus bradycardia and heart block Side Effects of Toxicity: Nystagmus, ataxia, confusion, nausea, slurred speech, and dizziness.  Caution patients to carry a medical alert card.
Procainamide (Promestyl)	Therapeutic: 5-12 mcg/ml Toxic: >15 mcg/ml Contraindicated in: AV block and myasthenia gravis Side Effects of Toxicity: Confusion, dizziness, drownsiness, decreased urination, nausea, vomiting, and tachyarrhythmias.
Primidone (Mysoline)	Therapeutic: 5-10 mcg/ml Toxic: >15 mcg/ml Contraindicated in: Porphyria Side Effects of Toxicity: Ataxia, lethargy, changes in vision, confusion, and dyspnea.  Caution patients to carry a medical alert card.
Propranolol (Inderal)	Therapeutic: Varies Toxic: Vaires Contraindicated in: Uncompensated congestive heart failure, pulmonary edema, cardiogenic shock, bradycardia, and heart block Side Effects of Toxicity: Bradycardia, severe dizziness or fainting, severe drowsiness, dyspnea, bluish fingernails or palms, and seizures. Caution diabetic patients to monitor blood sugar.
Quinidine	Therapeutic: 2-6 mcg/ml Toxic: >8 mcg/ml Contraindicated in: Conduction defects and digitalis glycoside toxicity Side Effects of Toxicity: Tinnitus, hearing loss, visual disturbances, headache, nausea, and dizziness.  Cardiotoxicity signs include QRS widening, cardiac asystole, ventricular ectopic beats, idioventricular rhythms, paradoxical tachycardia, and arterial embolism.
Salicylate	Therapeutic: Varies Toxic: Varies Contraindicated in: Hypersensitivity to aspirin or other salicylates, bleeding disorders or thrombocytopenia Side Effects of Toxicity: Tinnitus, headache, hyperventilation, agitation, mental confusion, lethargy, diarrhea, and sweating. May take 2 to 3 weeks for maximum effectiveness.
Theophylline	Therapeutic: 10-20 mcg/ml Toxic: >20 mcg/ml Contraindicated in: Uncontrolled arrhythmias and hyperthyroidism Side Effects of Toxicity: Anorexia, nausea, vomiting, stomach cramps, diarrhea, confusion, headache, restlessness, flushing, increased urination, insomnia, tachycardia, arrhythmias, and seizures. Tachycardia, ventricular arrhythmias, or seizures may be the first sign of toxicity.
Valproic Acid (Depakene)	Therapeutic: 50-100 mcg/ml Toxic: >100 mcg/ml Contraindicated in: Hepatic impairment Side Effects of Toxicity: Anorexia, severe nausea an dvomiting, yellow skin or eyes, fever, sore throat, malaise, weakness, facial edema, lethargy, unusual bleeding or bruising, or seizures.

Drugs	Troughs	Peaks
Amikacin	5 mcg/ml	35 mcg/ml
Gentamicin	2 mcg/ml	10 mcg/ml
Kanamycin	5 mcg/ml	35 mcg/ml
Neomycin	2 mcg/ml	16 mcg/ml
Streptomycin	Varies	25 mcg/ml
Tobramycin	2 mcg/ml	20 mcg/ml
Vancomycin	5-10 mcg/ml	25 mcg/ml

Aminoglycosides must be monitored carefully for side effects including ototoxicity (vestibular and cochlear), nephrotoxicity, neurotoxicity, and hypersensitivity reactions. Monitor patients for tinnitus, vertigo, hearing loss, rash, dizziness, or difficulty urinating. 

Renal lab tests that must be monitored include urinalysis, specific gravity, BUN, creatinine, and creatinine clearance. 

Liver lab tests that must be monitored include , AST (SGOT), ALT (SGPT), serum alkaline phosphatase, bilirubin, creatinien, and LDH concentrations.

Trough# levels are referred to as the minimum drug concentration that proceeds the administration of a single dose of medication. Trough levels should be drawn just prior to the next dose.

Peak* levels are referred to as the maximum drug concentration that follows the administration of a single dose of medication. Peak levels should be drawn 1 hour after IM injections and 30 minutes after a 30-minute IV infusion is completed. 

Drug	Antidote
Acetaminophen	Acetylcysteine
Anticholinesterases (Cholinergics)	Atropine, Pralidoxime
Antidepressants (MAO inhibitors and tryamine-containing foods may lead to hypertensive crisis including symptoms of chest pain, severe headache, nuchal rigidity, nausea and vomiting, photosensitivity, and enlarged pupils)	Phentolamine
Benzodiazepines	Flumazenil
Cyanide	Amyl nitrite, sodium nitrite, sodium thiosulfate
Digoxin, digitoxin	Digoxin immune Fasb (Digibind)
Fluorouracil (5FU)	Leucovorin calcium
Heparin	Portamine sulfate
Ifosfamide (Adverse effects cause hemorrhagic cystitis)	Mesna
Iron	Deferoxamine
Lead	Edetate calcium disodium, dimeraprol, succimer
Methotrexate (Adverse effects cause folic acid deficiency)	Leucovorin calcium
Opioid analgesics, heroin	Nalmefene, Naloxone
Thrombolytic agents	Aminocaproic acid (Amicar)
Tricyclic antidepressants	Physostigmine
Warfarin (Coumadin)	Phytonadione (Vitamin K)

Insulin	Onset	Peak	Duration
Regular IV	10-30 min	15-30 min	30-60 min
Regular SC	30 min-1hr	2-4 hr	5-7 hr
NPH	1-4 hr	6-12 hr	18-28 hr
Lente	1-3 hr	8-12 hr	18-28 hr
Ultralente	4-6 hr	18-24 hr	36 hr

Monitor patients for onset of HYPOGLYCEMIA reaction that typically occurs during the Peak Phase following administration of insulin. Signs and symptoms of HYPOGLYCEMIA include mental confusion, hallucinations, convulsions, pale, cool, clammy skin, tachycardia, and anxiety. Treatment includes the administration of oral glucose. Severe hypoglycemia is life-threatening and requires treatment with IV glucose, glucagon, or epinephrine. 

Signs and symptoms of HYPERGLYCEMIA include polyuria, polydipsia, and polyphagia, hot, red, and dry skin. Treatment includes insulin administration. Severe hyperglycemia is usually caused by missing, miscalculating or mistiming doses of insulin or oral medication or by overeating or drinking. Severe hyperglycemia is life-threatening and requires treatment with IV replacement and IV insulin.