Therapeutic Drug Levels Flashcards
Digoxin
LEVELS:
0.8 - 2 Micrograms per litre (mcg/L)
Drug CLASSES:
antiarrhythmic; cardiac glycoside; inotropic agent
MECHANISM:
1. inhibits the “sodium pump,” also called the sodium-potassium ATPase pump, in your heart.
2. (+) inotropic: Increases the force of myocardial contraction ( contractility)
4. (-) chronotropic: decreases heart rate - Prolongs refractory period of the AV node
3. (-) dromotropic: Decreases conduction through the SA and AV nodes
= increased CO
INDICATIONS:
1. Heart Failure
2. A-Fib
3. Paroxysmal atrial tachycardia.
CONSIDERATIONS:
1. Store in a place that is not exposed to direct sunlight.
2. monitor for toxicity
* HOLD DOSE and notify MD*
3. CHECK APICAL PULSE - 1 full min
*** HOLD DOSE if < 60 BPM (adult), 70 BPM ( CHILD) before admin
CAUTIONS:
1. Hypokalemia (↑ risk of digoxin toxicity);
2. Hypercalcemia (↑ risk of toxicity, especially with mild hypokalemia);
3. Hypomagnesemia (↑ risk of digoxin toxicity);
4. Diuretic use (may cause electrolyte abnormalities including hypokalemia and hypomagnesemia)
SIDE EFFECTS (* common)
CV: *bradycardia, ARRHYTHMIAS!, ECG changes, heart block
EENT: blurred vision, yellow or green vision
GI: *anorexia, *nausea, *vomiting, diarrhea
Hemat: thrombocytopenia
Neuro: fatigue, headache, weakness
SINGS OF TOXICITY:
Confusion, loss of appetite, nausea, vomiting, diarrhea, or vision problems ( yellow/green halo)
Lithium
0.8 - 1.2 millimoles per litre (mmol/L)
NAME:
Antimanic drug
Carbolith Canadian Trade name
Lithane Canadian Trade name
Lithmax Canadian Trade name
Lithobid
USE:
Treatment of manic episodes of manic-depressive illness; maintenance therapy to prevent or diminish frequency and intensity of subsequent manic episodes
RESPONSIBILITIES:
Monitor for toxicity
Mild symptoms:
Diarrhea, vomiting, lethargy, tremor, and fatigue
Moderate intoxication:
confusion, agitation, delirium, tachycardia, and hypertonia
COMMON SIDE EFFECTS:
nausea, polyuria, polydipsia, fine hand tremors
CONTRAINDICATIONS:
Severe renal and cardiac disease; severe dehydration, sodium depletion
Theophylline
10 -20 Micrograms per litre (mcg/L)
CLASS:
Bronchodilator
ACTION:
Theophylline competitively blocks phosphodiesterase which increases cAMP tissue concentrations causing bronchodilatation, diuresis, CNS and cardiac stimulation, and gastric acid secretion.
INDICATION:
Symptomatic relief or prevention of bronchial asthma and reversible bronchospasm associated with chronic bronchitis and emphysema
ADVERSE EFFECTS:
Nausea, vomiting, abdominal pain, diarrhea, headache, insomnia, dizziness, anxiety, restlessness, tremor, palpitations.
Potentially Fatal: Convulsions, cardiac arrhythmias, hypotension and sudden death after too rapid IV injection
TEACHING:
1. If a timed-release product is prescribed, take it on an empty stomach, 1 hour before or 2 hours after meals
2. avoid caffein - may increase side effects
3. Smoking cigarettes or other tobacco products may markedly influence the effects of theophylline.
TOXICITY:
Gastrointestinal signs and symptoms are common in acute theophylline toxicity. Nausea and vomiting are generally present and occasionally are associated with hematemesis. Diarrhea has been observed.
Phenytoin
10 - 20 milligrams per liter (mg/L)
CLASS:
(dilantin)
Antiepileptic, Antiarrhythmic, group 1b, Hydantoin
INDICATIONS:
Control of grand mal (tonic-clonic) and psychomotor seizures
Prevention and treatment of seizures occurring during or following neurosurgery
Potentially Fatal:
1. Toxic epidermal necrolysis (TEN),
> severe form of SJS, when 30% of the skin surface is affected
2. Stevens-Johnson syndrome (SJS)
>starts with flu-like symptoms, followed by a painful rash that spreads and blisters. Then the top layer of affected skin dies, sheds and begins to heal after several days.
CONTRAINDICATIONS:
Pregnancy. IV admin in sinus bradycardia, heart block, or Stokes-Adams syndrome.
CONSIDERATIONS:
1. Do not use solutions that have haziness or a precipitate
2. WARNING: Administer IV slowly to prevent severe hypotension; the margin of safety between full therapeutic and toxic doses is small. Continually monitor patient’s cardiac rhythm and check BP frequently and regularly during IV infusion
3. Monitor injection sites carefully; drug solutions are very alkaline and irritating.
4. Do not discontinue this drug abruptly or change dosage, except on the advice of your health care provider
Symptoms of a phenytoin overdose may include:
Coma
Confusion
Seizures (occasionally)
Dizziness
Fever
Low blood pressure
Muscle rigidity or spasms
Sleepiness
Side-to-side eye movement (nystagmus)
Slurred speech
Swollen gums
Tremor (unintentional trembling)
Unsteadiness
Vancomycin
10 to 15 mg/L
A peak is drawn 1-2 hours after a dose is complete.
a trough is drawn right before the next dose is administered.
