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31 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What are the common adverse effect of ketoconazole?
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anorexia, nausea and vomiting
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The most frequent adverse effects of ketoconazole are anorexia, nausea, and vomiting, which occur in about 15% to 29% of patients. Allergic rash, headache, and pruritus are seen in 4% to 10% of patients. Mild elevations in liver transaminases occur in 2% to 5% of patients during the course of therapy. However, the most serious adverse effect associated with ketoconazole therapy is fulminant hepatitis. This occurs rarely, in 1 in 15,000 exposed individuals. Arrhythmias and seizures have not been associated with the use of this drug.
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How does ketoconazole work?
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It inhibits the biosynthesis of ergosterol and other membrane lipids that compose the fungal cell membrane resulting in increased permeability and progressive instability of the
fungal cell membrane. |
Ketoconazole is an imidazole antifungal agent that works by inhibiting the biosynthesis of ergosterol and other membrane lipids that compose the fungal cell membrane. Such inhibition results in fungal cellular membranes that lack the sterol components, causing increased permeability and progressive instability.
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What presents as coma, respiratory depression, tachycardia, hypotension, dilated pupils, seizures, dysrhythmias, dry mouth, hyperthermia, urinary retention, flushed skin and agitation.
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Acute tricyclic antidepressant (TCA) overdose.
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The coma, respiratory depression, tachycardia, hypotension, and dilated pupils described for the patient in the vignette are consistent with an acute tricyclic antidepressant (TCA) overdose. Among the additional signs that might be observed are seizures, dysrhythmias, and other anticholinergic features such as dry mouth, hyperthermia, urinary retention, flushed skin, and agitation. Tricyclic antidepressants cause these clinical features by inhibiting a variety of neurotransmitter receptors, including muscarinic acetylcholine, alpha-1-adrenergic, gamma aminobutyric acid (GABA), and histamine receptors as well as cardiac fast sodium channels.
The most serious toxicities from TCA overdose affect the heart and central nervous system (CNS). Because of the TCA effect on fast sodium channels, conduction velocity is decreased. In addition, repolarization duration and absolute refractory periods are prolonged. These effects, coupled with alpha-1-adrenergic antagonism, are responsible for the hypotension and conduction delays that are seen commonly. CNS excitation and seizures or depression may be related to effects on GABA or histamine receptors. |
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How do you treat TCA overdose?
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ABCs then treat seizures with benzodiazepines, treat hypotension with fluids and alpha-adrenergic pressors, and widened QRS with sodium bicarbonate.
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Initial management of a TCA overdose begins with ensuring a patent airway and restoring adequate oxygenation, ventilation, and perfusion. Intubation and mechanical ventilation often are necessary, as is fluid resuscitation with boluses of normal saline. Seizures are treated with benzodiazepines. Alpha-adrenergic pressors (eg, norepinephrine) may be required to treat refractory hypotension. Decontamination should be performed with activated charcoal. Although acetaminophen and aspirin concentrations should be measured, especially in intentional ingestions to evaluate for possible coingestants, measurement of TCA concentrations is not clinically useful.
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What is the single most useful diagnostic and prognostic test in the setting of a TCA overdose?
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EKG
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In a study from 1985, toxicologists found that a QRS duration of greater than 100 msec predicted seizures in 34% and dysrhythmias in 14% of patients who had TCA overdoses. The QRS widening is related to fast sodium channel blockade caused by direct TCA effects and exacerbated by acidemia. These effects can be overcome by the administration of sodium bicarbonate boluses. Sodium bicarbonate should be administered until the QRS duration is less than 100 msec. The exact mechanism for this effect is unknown.
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How do inotropic agents work?
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They increase the contractility of the heart.
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What effect does dopamine have at low doses?
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Coronary and renal perfusions are enhanced.
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What effect does dopamine have at high does?
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alpha-adrenoreceptor stimulation causes vasoconstriction, increased afterload and a decrease in renal blood flow.
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What receptors does dobutamine act on?
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beta1-adrenergic effects which stimulates myocardial contractility.
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What receptors does epinephrine work on?
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alpha and beta adrenoreceptors.
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How does digoxin work?
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By inhibiting the sodium pump (Na+-K ATPase) and subsequently increased Na-Ca2+ which increases inotrope response
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What drugs increase digoxin levels?
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quinidine, verapamil, amiodarone, beta-blockers, tetracycline and erythromycin
BEAT VQ |
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What drugs decrease digoxin levels?
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Cholestyramine
Rifampin Neomycin CRN |
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What toxicity usually presents with nausea, vomiting and diarrhea with potential color-vision changes, confusion, vertigo, paplpitations and arrythmias.
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Digoxin toxicity
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Where do loop diuretics work?
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Ascending limb of the loop of Henle
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What ions accumulate in the tubular lumen and get flushed in urine with use of loop diuretics?
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Na+
K+ H+ Cl- |
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What is the most common side effect of loop diuretics?
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Hypokalemia
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What drugs affect the cortical diluting segment?
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Thiazides and metolazone.
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What ions are affected by thiazide diuretics?
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Increase potassium loss and decrease calcium excretion
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Where do potassium sparing diuretics work?
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The distal tubule
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What is the common and more unusual side effect of spironolactone?
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Hyperkalemia is common
Gynecomastia less common |
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How do ACE inhibitors work?
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They inhibit the maladaptive neurohumoral forces initiated by the renin-angiotensin-aldosterone system.
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Are ACE inhibitors useful in severe, chronic CHF?
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Yes
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Are ACE inhibitors useful in dilated cardiomyopathy?
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Yes
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Are ACE inhibitors useful in restrictive cardiomyopathy?
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No
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Are ACE inhibitors useful in restrictive cardiomyopathy?
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No
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Are ACE inhibitors useful in diastolic dysfunction?
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No
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Are ACE inhibitors useful in left-to-right shunts?
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Yes
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Is ACE inhibitor related cough common in children?
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No - only in adults
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What side effects of ACE inhibitors need to be monitored for?
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Hyperkalemia
Elevated creatinine and Angioedema |
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Are beta-blockers contraindicated in CHF?
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Not anymore - but low dose
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