Codeine

What is codeine?

Codeine (brand names: Codeine Contin®, Codeine Phosphate®, Codeine Sulfate®, Codeine 15 or 30) is an opioid medication used to treat mild to moderate pain, cough, and sometimes diarrhea.

In the United States and Canada, codeine is considered a controlled substance, which means there are strict rules regarding how it is prescribed, dispensed, and used.

Codeine combined with other medications is also controlled, but typically combination drugs have different restrictions.

Its use in cats and dogs to treat pain, cough, and diarrhea is off label (extra label). Many drugs are commonly prescribed for off-label use in veterinary medicine. 

“Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is codeine given?

• Codeine is given by mouth in the form of a tablet or liquid solution. It may also be given as an injection in the hospital.
• Measure liquid forms carefully.
• Codeine may be given with or without food.
• If stomach upset occurs when dosed on an empty stomach, give future doses with food.
• Do not give the combination product containing acetaminophen (Tylenol®) to cats or ferrets.

This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then wait the recommended time as prescribed by your veterinarian for the next dose. Do not give the pet two doses at once.

Are there any potential side effects?

Codeine may cause the following side effects:

• Sleepiness
• Constipation
• Lack of appetite
• Vomiting

Serious adverse reactions may occur. If any of the following signs develop, stop giving codeine and contact your veterinarian immediately:

• Collapse
• Severely decreased breathing rate
• Decreased muscle movement

In cats, serious side effects also include:

• Increased excitement
• Tremors
• Seizures

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately.  This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

DO NOT USE any codeine/acetaminophen combination product in cats or ferrets.

DO NOT USE codeine in pets that:

• Are allergic to it or other opioids
• Have inflammatory bowel disease
• Have ingested a toxic substance

USE WITH CAUTION in pets that:

• Have low thyroid levels
• Have severe kidney disease
• Have head injury
• Have breathing problems
• Have heart disease or adrenal gland disease
• Are working, geriatric, or debilitated
• Are pregnant or lactating (appears safe but use cautiously)

Are there any drug interactions I should be aware of?

Several medications should be used with caution when given with codeine, including:

• Anticholinergic drugs
• Antidepressants
• Central nervous system depressants such as anesthetics, barbiturates, or tranquilizers

Certain medications may interact with codeine, so be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any new treatment.

Is any monitoring needed with this medication?

• Your veterinarian will let you know when and how they want to reassess your pet to ensure the medication is working and not causing side effects.
• At home, monitor for any side effects such as those noted above. If any occur, stop using the medication and contact your veterinarian.

How do I store codeine?

• Codeine commercial products should be stored at room temperature and protected from light.
• For specially compounded formulations, follow the specific storage directions on the label.

Codeine is a controlled substance, which means that it has been designated by the Drug Enforcement Administration (DEA) as having a potential for diversion to people other than the patient it was prescribed for. Use of a controlled substance in any person or animal other than that for which it is prescribed is illegal. Therefore, this medication should be stored in a locked cabinet or safe that cannot be easily moved, with access limited to only those that need to administer the medication. Monitor the amount of medication remaining to ensure the expected amount is present.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet’s weight and symptoms.