HYDROCODONE BITARTRATE
Chemistry - A phenanthrene-derivative opiate agonist, hydrocodone bitartrate occurs as fine, white crystals or crystalline powder. One gram is soluble in about 16 mls of water; it is slightly soluble in alcohol. This compound may also be known as dihydrocodeinone bitartrate.
Hydrocodone may also be more sedating than codeine, but not more constipating.
There does not appear to be any pharmacokinetic data published in dogs. The antitussive actiongenerally persists for 6-12 hours.
Contraindications/Precautions - Hydrocodone is contraindicated in cases where the patient ishypersensitive to narcotic analgesics and in patients taking monoamine oxidase inhibitors(MAOIs). It is also contraindicated in patients with diarrhea caused by a toxic ingestion until thetoxin is eliminated from the GI tract. All opiates should be used with caution in patients with hypothyroidism, severe renal insufficiency, adrenocortical insufficiency (Addison's), and in geriatricor severely debilitated patients.
Hydrocodone should be used with caution in patients with head injuries or increased intracranialpressure and acute abdominal conditions as it may obscure the diagnosis or clinical course of theseconditions. It should be used with extreme caution in patients suffering from respiratory diseaseswhen respiratory secretions are increased or when liquids are nebulized into the respiratory tract.
Hydrocodone may mask the symptoms (cough) of respiratory disease and should not take theplace of appropriate specific treatments for the underlying cause of coughs.Overdosage - The initial concern with a very large overdose of Hycodan® (or equivalent) would bethe CNS, cardiovascular and respiratory depression secondary to the opiate effects. If the ingestionwas recent, emptying the gut using standard protocols should be performed and treatment withnaloxone instituted as necessary. The homatropine ingredient may give rise to anticholinergiceffects which may complicate the clinical picture, but its relatively low toxicity may not require anytreatment. For further information on handling opiate or anticholinergic overdoses, refer to themeperidine and atropine monographs, respectively.
Storage, Stability, Compatibility
Products should be protected from light.Pharmacology - HYDROCODONE BITARTRATE
While hydrocodone exhibits the characteristics of other opiate agonists (see themonographs on opiates in the CNS section), it tends to have a slightly greater antitussive effect thancodeine (on a weight basis). The mechanism of this effect is thought to be as a result of directsuppression of the cough reflex on the cough center in the medulla. Hydrocodone also tends tohave a drying effect on respiratory mucosa and the viscosity of respiratory secretions may beincreased. The addition of homatropine MBr (in Hycodan® and others) may enhance this effect.Hydrocodone may also be more sedating than codeine, but not more constipating.
Uses, Indications
Used principally in canine medicine as an antitussive for cough secondary toconditions such as collapsing trachea, bronchitis, or canine upper respiratory infection complex (C-URI, "kennel cough", canine infectious tracheobronchitis). Its use is generally reserved for harsh, dry, non-productive coughs.Pharmacokinetics - HYDROCODONE BITARTRATE
In humans, hydrocodone is well absorbed after oral administration, and has aserum half-life of about 3.8 hours. Antitussive effect usually lasts 4-6 hours in adults.There does not appear to be any pharmacokinetic data published in dogs. The antitussive actiongenerally persists for 6-12 hours.
Contraindications/Precautions - Hydrocodone is contraindicated in cases where the patient ishypersensitive to narcotic analgesics and in patients taking monoamine oxidase inhibitors(MAOIs). It is also contraindicated in patients with diarrhea caused by a toxic ingestion until thetoxin is eliminated from the GI tract. All opiates should be used with caution in patients with hypothyroidism, severe renal insufficiency, adrenocortical insufficiency (Addison's), and in geriatricor severely debilitated patients.
Hydrocodone should be used with caution in patients with head injuries or increased intracranialpressure and acute abdominal conditions as it may obscure the diagnosis or clinical course of theseconditions. It should be used with extreme caution in patients suffering from respiratory diseaseswhen respiratory secretions are increased or when liquids are nebulized into the respiratory tract.
Adverse Effects, Warnings
Side effects that may be encountered with hydrocodone therapy indogs include: sedation, constipation (with chronic therapy), vomiting or other GI disturbances.Hydrocodone may mask the symptoms (cough) of respiratory disease and should not take theplace of appropriate specific treatments for the underlying cause of coughs.Overdosage - The initial concern with a very large overdose of Hycodan® (or equivalent) would bethe CNS, cardiovascular and respiratory depression secondary to the opiate effects. If the ingestionwas recent, emptying the gut using standard protocols should be performed and treatment withnaloxone instituted as necessary. The homatropine ingredient may give rise to anticholinergiceffects which may complicate the clinical picture, but its relatively low toxicity may not require anytreatment. For further information on handling opiate or anticholinergic overdoses, refer to themeperidine and atropine monographs, respectively.