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THE PET PHARMACY
By Wendy C. Brooks, DVM, DipABVP
Educational Director, VeterinaryPartner.com

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Hydrocodone Bitartrate (Hycodan, Tussigon, Mycodone)

Brand Name: Hycodan, Tussigon, Mycodone or Hydroment

Available in 5 mg tablets and oral syrup

Background

Despite their reputation for recreational euphoria, narcotics have numerous therapeutic effects which are of interest in the clinical setting. Such effects include: pain relief, anti-diarrheal effects, cardiovascular effects, and cough suppression.  Hydrocodone is a narcotic developed to accentuate its cough suppression effect though it still retains fair analgesic effects as well. It is somewhat more effective than codeine (another famous narcotic used in cough suppression) but possibly not as widely used in human medicine.

Hydrocodone suppresses cough directly by acting on the cough centers of the brain but it is also helpful in drying the respiratory secretions so that there is less material to cough up. This drying effect is further enhanced by the addition of homatropine, a second compounded added to most hydrocodone products. While homatropine may enhance the drying of secretions, it is mainly added to reduce abuse potential of the hydrocodone. In the event of gross over-consumption, the homatropine will lead to unpleasant side effects, thus limiting the amount of hydrocodone that can be consumed.

How this Medication is Used

Some typical situations in which cough suppression with hydrocodone would be helpful include:

  • Kennel cough (a usually minor infection leading to bronchitis).
  • Collapsing trachea (where the windpipe becomes flimsy).
  • "Old dog" bronchitis (a natural part of aging in dogs involves excess mucus production in the lungs).
  • Heart enlargement (where the right chambers of the heart become so large that as the heart beats they pinch off the main airways).

These are all conditions where minor secretions or actual tissues are pressing on the lung's airways and stimulating cough.  Coughs that benefit from suppression are typically dry and hacking, often described as sounding as though something is stuck in the throat.

In dogs, a dose of hydrocodone is believed to last approximately 6 to 12 hours. Hydrocodone is typically dosed four times a day or less, as needed.

Side Effects

The chief side effects of hydrocodone use include:

  • Drowsiness or tranquilization
  • Drying of respiratory secretions
  • Constipation (if hydrocodone is given chronically)
  • Upset stomach

Notify your veterinarian if any of these side effects appear to be causing discomfort.

Interactions with other Drugs

Serious side effects have been reported involving interactions between Anipryl/L-Deprenyl (treatment for senility in dogs as well as for Cushing's disease in dogs) and mepiridine (more commonly known as Demerol®, another narcotic). Based on this, the recommendation to avoid the use of Anipryl/L-deprenyl with any narcotics has been proposed; a different cough suppressant should be sought in such cases.

Mixing hydrocodone with other tranquilizers or with antihistamines increases the sedative side effects. (Note, there is a human product, brand name Tussionex®, which combines hydrocodone and the antihistamine chlorpheniramine. Clearly there are many human respiratory infections for which an antihistamine and cough suppressant combination might be beneficial, but the sedation effects will be increased.)

Combination of hydrocodone and acepromazine, a tranquilizer, can not only lead to extreme sedation but can also lead to a serious drop in blood pressure.

If hydrocodone is combined with an antidepressant, excessive sedation can result from this combination.

Concerns and Cautions

  • Cough suppression is not appropriate in the event of pneumonia. In pneumonia, there is excessive pus and mucus accumulation in the lung and this material must be coughed up.  Suppressing the cough and drying the secretions will hinder the body's removal of this septic material.
  • Narcotic cough suppressants should be avoided in cases involving obstructive diarrheas or toxic diarrheas (such as canine parvovirus infection). The narcotic will improve the intestinal tone, which will assist in absorbing water from the bowel and will improve stool consistency; however, it will also facilitate toxic absorption as well. In such situations, other forms of diarrhea treatment would be more appropriate.
  • There are human formulations of hydrocodone that include acetaminophen. Acetaminophen has a narrow therapeutic range in dogs (meaning dosing must be very exact) and is not safe at any dose in cats. It is best not to attempt to use a hydrocodone preparation if it was not directly prescribed by your veterinarian for a specific patient.
  • Opiates should be used with caution in patients with hypothyroidism, hypoadrenocorticism (Addison's disease), or debilitation from other diseases.

Hydrocodone bitartrate is a controlled substance and specific paperwork is necessary for its prescription.

It is our policy not to give dosing information over the Internet.

 

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