EPHEDRINE SULFATE
Chemistry - A sympathomimetic alkaloid, ephedrine sulfate occurs as fine, odorless, white crystalsor powder. Approximately 770 mg are soluble in one ml of water. The commercially availableinjection has a pH of 4.5-7.
Pharmacologic effects of ephedrine include increased vasoconstriction, heart rate, coronary bloodflow, blood pressure, mild CNS stimulation, and decreased bronchoconstriction, nasal congestionand appetite. Ephedrine can also increase urethral sphincter tone and produce closure of the bladderneck; its principle veterinary indications are as a result of these effects.
Uses, Indications - Ephedrine is used chiefly for the treatment of urethral sphincter hypotonus andresulting incontinence in dogs and cats. It has also been used in an attempt to treat nasal congestionand/or bronchoconstriction in small animals. It potentially could be used parenterally as a pressoragent in the treatment of shock, but veterinary use is very limited for this indication.
Although not confirmed, ephedrine is thought to cross both the blood-brain barrier and the placenta.
Ephedrine is metabolized in the liver and excreted unchanged in the urine. Urine pH maysignificantly alter excretion characteristics. In humans: at urine pH of 5, half life is about 3 hours; aturine pH of 6.3, half life is about 6 hours.
Overdosage - Symptoms of overdosage may consist of an exacerbation of the adverse effects listedabove or, if a very large overdose, severe cardiovascular (hypertension to rebound hypotension, bradycardias to tachycardias, and cardiovascular collapse) or CNS effects (stimulation to coma) canbe seen.
If the overdose was recent, empty the stomach using the usual precautions and administer charcoaland a cathartic. Treat symptoms supportively as they occur.
Ephedrine should not be given within two weeks of a patient receiving monoamine oxidaseinhibitors.
An increased chance of hypertension developing can result if ephedrine is given concomitantlywith indomethacin (or other NSAIDs, including aspirin), reserpine, tricyclic antidepressants, or ganglionic blocking agents.
An increased risk of arrhythmias developing can occur if ephedrine is administered to patients who have received cyclopropane or a halogenated hydrocarbon anesthetic agent. Propranolol may be administered should these occur.
Urinary alkalinizers (e.g., sodium bicarbonate, citrates, carbonic anhydrase inhibitors) may reduce the urinary excretion of ephedrine and prolong its duration of activity. Dosage adjustments may be required to avoid toxic symptoms.
Concomitant use of ephedrine with beta blockers may diminish the effects of both drugs.
An increased risk of arrhythmias may occur if ephedrine is used concurrently with digitalis glycosides.
Laboratory Considerations - beta adrenergic agonists may decrease serum potassium concentrations. Clinical relevance is uncommon.
Storage, Stability, Compatibility
Store ephedrine sulfate products in tight, light resistant containers at room temperature unless otherwise directed.Pharmacology - EPHEDRINE SULFATE
While the exact mechanism of ephedrine's actions are undetermined, it is believedthat it indirectly stimulates both alpha-, beta1, beta2-adrenergic receptors by causing the release ofnorepinephrine. Prolonged use or excessive dosing frequency can deplete norepinephrine from itsstorage sites and tachyphylaxis (decreased response) may ensue. Tachyphylaxis has not beendocumented in dogs or cats, however, when used for urethral sphincter hypotonus.Pharmacologic effects of ephedrine include increased vasoconstriction, heart rate, coronary bloodflow, blood pressure, mild CNS stimulation, and decreased bronchoconstriction, nasal congestionand appetite. Ephedrine can also increase urethral sphincter tone and produce closure of the bladderneck; its principle veterinary indications are as a result of these effects.
Uses, Indications - Ephedrine is used chiefly for the treatment of urethral sphincter hypotonus andresulting incontinence in dogs and cats. It has also been used in an attempt to treat nasal congestionand/or bronchoconstriction in small animals. It potentially could be used parenterally as a pressoragent in the treatment of shock, but veterinary use is very limited for this indication.
Pharmacokinetics - EPHEDRINE SULFATE
Ephedrine is rapidly absorbed after oral or parenteral administration.Although not confirmed, ephedrine is thought to cross both the blood-brain barrier and the placenta.
Ephedrine is metabolized in the liver and excreted unchanged in the urine. Urine pH maysignificantly alter excretion characteristics. In humans: at urine pH of 5, half life is about 3 hours; aturine pH of 6.3, half life is about 6 hours.
Contraindications, Precautions, Reproductive Safety
Ephedrine is contraindicated in patientswith severe cardiovascular disease, particularly with arrhythmias. Ephedrine should be used withcaution in patients with glaucoma, prostatic hypertrophy, hyperthyroidism, diabetes mellitus, cardiovascular disorders or hypertension. Ephedrine's effects on fertility, pregnancy or fetal safetyare not known. Use with caution during pregnancy. The drug is excreted in milk and may havedeleterious effects on nursing animals.Adverse Effects, Warnings
Most likely side effects include restlessness, irritability, tachycardia, hypertension. Anorexia may be a problem in some animals.Overdosage - Symptoms of overdosage may consist of an exacerbation of the adverse effects listedabove or, if a very large overdose, severe cardiovascular (hypertension to rebound hypotension, bradycardias to tachycardias, and cardiovascular collapse) or CNS effects (stimulation to coma) canbe seen.
If the overdose was recent, empty the stomach using the usual precautions and administer charcoaland a cathartic. Treat symptoms supportively as they occur.
Drug Interactions
Ephedrine should not be administered with other sympathomimetic agents(e.g., phenylpropanolamine) as increased toxicity may result.Ephedrine should not be given within two weeks of a patient receiving monoamine oxidaseinhibitors.
An increased chance of hypertension developing can result if ephedrine is given concomitantlywith indomethacin (or other NSAIDs, including aspirin), reserpine, tricyclic antidepressants, or ganglionic blocking agents.
An increased risk of arrhythmias developing can occur if ephedrine is administered to patients who have received cyclopropane or a halogenated hydrocarbon anesthetic agent. Propranolol may be administered should these occur.
Urinary alkalinizers (e.g., sodium bicarbonate, citrates, carbonic anhydrase inhibitors) may reduce the urinary excretion of ephedrine and prolong its duration of activity. Dosage adjustments may be required to avoid toxic symptoms.
Concomitant use of ephedrine with beta blockers may diminish the effects of both drugs.
An increased risk of arrhythmias may occur if ephedrine is used concurrently with digitalis glycosides.
Laboratory Considerations - beta adrenergic agonists may decrease serum potassium concentrations. Clinical relevance is uncommon.