What is Domperidone?
Domperidone is a dopamine receptor antagonist that is used to treat gastrointestinal motility disorders and as an anti-emetic in dogs and cats (DrugBank, 2022). It works by blocking dopamine D2 receptors in the chemoreceptor trigger zone, which reduces nausea and vomiting. Domperidone also increases motility in the upper gastrointestinal tract by increasing acetylcholine release and decreasing dopamine levels in the myenteric plexus (Reddymasu et al., 2007).
In veterinary medicine, domperidone is commonly used to treat vomiting, regurgitation, and delayed gastric emptying in dogs and cats. It helps improve gastric motility and the coordination between the stomach and small intestine. Domperidone also stimulates appetite by blocking dopamine’s inhibitory effects on hunger signaling. For this reason, it may be prescribed in cases of inappetence and anorexia. Overall, domperidone is an effective prokinetic agent and anti-emetic in dogs.
Why Use Domperidone for Dogs?
Domperidone may be prescribed for dogs experiencing vomiting, nausea, or lack of appetite due to its prokinetic and antiemetic properties (Travi, 2021). This medication helps regulate gastrointestinal motility and movement. Specifically, domperidone acts as a D2 dopaminergic antagonist, blocking dopamine receptors that inhibit gastric contractions, and causing the stomach to contract more normally (Todays Veterinary Practice, n.d.). This helps with gastric emptying and can reduce nausea and vomiting.
Domperidone’s prokinetic effects make it useful for managing various causes of vomiting in dogs, such as gastric motility disorders, food reactions, motion sickness, vestibular disease, and side effects of medications. By improving gastric emptying and decreasing nausea, domperidone can help resolve vomiting episodes and improve appetite (Vet Depot, n.d.). Domperidone may also be used to manage vomiting and gastroesophageal reflux in some chronic diseases like Leishmaniasis (Travi, 2021).
How Does Domperidone Work?
Domperidone is a peripheral dopamine 2 (D2) receptor antagonist that works by blocking dopamine receptors in the upper gastrointestinal tract, specifically in the chemoreceptor trigger zone, gastric fundus, antrum, and duodenum (Reddymasu, 2007). This increases motility in the upper gastrointestinal tract and improves gastric emptying. Domperidone does not readily cross the blood-brain barrier, so it has minimal effects on the central nervous system dopamine receptors that control nausea and vomiting (Brogden et al., 1982).
The main mechanisms of action of domperidone as an antiemetic and prokinetic agent are:
- Blocking D2 receptors in the chemoreceptor trigger zone – This decreases the stimulation of vomiting by emetogenic neurotransmitters like dopamine.
- Increasing acetylcholine release – Acetylcholine is a neurotransmitter that stimulates gastrointestinal motility.
- Antagonizing D2 receptors in the gastrointestinal tract – This enhances peristalsis and accelerates gastric emptying.
Through these effects, domperidone helps resolve nausea, vomiting, bloating, and other upper GI symptoms by improving gastric motility and emptying.
Domperidone Dosage for Dogs
The typical dosage range for domperidone in dogs is 0.05 to 0.1 mg/kg given 1-2 times daily. This is based on studies examining its efficacy for treating various conditions like vomiting, inappetence, and delayed gastric emptying in dogs.
For treating acute vomiting, the starting dose is often at the higher end around 0.1 mg/kg given 1-2 times daily. For ongoing management of conditions like delayed gastric emptying, the maintenance dosage may be lowered to 0.05-0.07 mg/kg once or twice daily.
According to one study examining domperidone for treating leishmaniasis in dogs, a dose of 0.5 mg/kg once daily for 30 days every 3 months was effective and well-tolerated [1]. However, this dosage is higher than typical recommendations.
Veterinarians may adjust the dosage up or down based on the individual dog’s response and tolerance. Domperidone is available in 10mg, 30mg and 60mg tablets that can be given whole, halved or quartered as needed to achieve the desired dose.
Key Factors in Dosing
There are several important factors to consider when determining the proper domperidone dose for a dog:
Body weight – Domperidone dosage should be calculated based on the dog’s body weight, with heavier dogs requiring higher doses. The typical starting dose is 0.5-1 mg/kg every 12 hours.
Condition being treated – Higher domperidone doses may be needed for certain conditions like gastroparesis or vomiting compared to improving milk production.
Response to treatment – The dose can be adjusted based on the dog’s response. If nausea and vomiting improve at a lower dose, a higher dose may not be necessary.
Breed – Some breeds like Collie dogs are more susceptible to side effects and may need lower doses.
Other medications – Domperidone can interact with some drugs like antibiotics and antifungals. Dosage adjustments may be required.[1]
Kidney and liver function – Impaired kidney or liver function may require lower domperidone doses to avoid toxicity.
Duration of therapy – Long term domperidone therapy requires monitoring and periodic dosage adjustments as needed.
Careful consideration of these factors along with monitoring helps determine the optimal domperidone dose for each dog while minimizing side effects.
Starting Doses
When first starting domperidone treatment for dogs with vomiting, typical starting doses are:
- Under 10 lbs: 1-2 mg per dog 2-3 times daily
- 10-20 lbs: 2-5 mg per dog 2-3 times daily
- 20-35 lbs: 5-10 mg per dog 2-3 times daily
- Over 35 lbs: 10 mg per dog 2-3 times daily[1]
For example, a 15 lb dog would start with an initial dose of 2-5 mg 2-3 times per day. Doses are typically given about 15-30 minutes before meals.
Veterinarians may start with lower doses and gradually increase over the first few days based on response and tolerability. It’s important to follow your vet’s specific dosing instructions. Starting with too high of a dose can increase the risk of side effects.
Maintenance Doses
After the starting dose, most dogs are maintained on 0.1-0.5 mg/kg of domperidone given 2-3 times daily according to this veterinary medication guide. The Merck Veterinary Manual recommends a maintenance dose of 0.1-0.5 mg/kg given orally for dogs as well (see their dosing table).
The maintenance dose can be adjusted up or down within the recommended ranges based on the dog’s response and tolerance. Smaller dogs may do well on doses at the lower end of the range, while larger dogs often require higher maintenance doses. The goal is to find the lowest effective dose that provides relief of vomiting and gastrointestinal issues.
If vomiting persists on the starting dose, veterinarians may slowly increase the maintenance dose incrementally up to the maximum recommended amount. However, higher doses increase the risk of side effects. Thus, the dose should be titrated carefully based on the individual dog’s needs.
The total daily dose can be divided into 2 or 3 doses spaced evenly throughout the day. For example, a 15 kg dog receiving 0.3 mg/kg could get 0.1 mg/kg (1.5 mg) every 8 hours. Giving the dose with meals may improve absorption. Most dogs do well on maintenance doses given 2-3 times daily long-term.
Dosing Frequency
Domperidone is typically dosed 2-3 times per day in dogs. Most commonly, it is given every 8-12 hours. However, the frequency may vary depending on the specific condition being treated.
For treating vomiting and nausea, domperidone is often given 2-3 times daily, as the effects last around 8-12 hours. Giving it every 8-12 hours helps maintain adequate drug levels to control vomiting and improve motility.
For increasing milk production in lactating dogs, some vets recommend dosing 3 times a day, such as every 8 hours. Frequent dosing helps maximize prolactin levels to stimulate milk production.
When used long-term to manage conditions like leishmaniasis, domperidone may be given just once or twice daily for maintenance. But the initial frequent dosing is important to get the condition under control.
Veterinarians may adjust the dosing frequency based on the individual dog’s response and the severity of symptoms. More frequent dosing up to 3 times daily may be needed initially in acute vomiting cases. Whereas less frequent dosing may suffice for maintenance therapy.
Administering Domperidone
Domperidone is available as an oral solution, tablet, or suspension for dogs. The oral solution or suspension is often easiest to administer. Give domperidone about 15-30 minutes before meals for maximum effectiveness.
When giving the oral solution, use the dropper or syringe provided to measure the dose. Administer the medication directly into the dog’s mouth or mix it into a small amount of wet food that the dog will consume immediately. Make sure the dog swallows the entire dose.
For tablet form, disguise the tablet in a highly palatable treat or food item if your dog is reluctant to take it. Tablets can also be crushed and mixed into wet food. Ensure the dog eats the entire portion with the crushed tablet.
If using a domperidone suspension, shake the bottle well before drawing up the proper dose amount into an oral syringe. Give the suspension directly into the dog’s mouth or mix it into a small amount of wet food. Make sure the dog consumes all of the food/suspension mixture.
Do not mix domperidone into dry kibble as it can reduce the medication’s absorption. Always administer doses consistently with food to optimize absorption and efficacy. Monitor the dog for several minutes after dosing to ensure the medication is swallowed and retained.
If administering the medication is difficult, speak to your veterinarian about compounding domperidone into a highly palatable transmucosal gel or other dog-friendly dosage form.
Monitoring and Precautions
It’s important to monitor your dog closely while they are on domperidone treatment. Look for side effects such as increased thirst, appetite changes, diarrhea, vomiting, restlessness, and abnormal involuntary movements. Contact your veterinarian if any of these persist or worsen.
Domperidone may increase the risk of arrhythmias, particularly in dogs with pre-existing cardiac issues. Your vet may recommend periodic ECG monitoring to watch for any heart rhythm abnormalities. Domperidone can also increase prolactin levels, so female dogs may start lactating. This side effect is generally not dangerous.
Do not combine domperidone with certain medications like ketoconazole, macrolides, and QT-prolonging drugs as they increase the risk of toxicity. Use caution when giving domperidone along with other prokinetics like metoclopramide or cisapride. Only give domperidone as prescribed and directed by your veterinarian.
Since domperidone is excreted in breast milk, caution should be exercised when administering domperidone to nursing dogs. Puppies ingesting domperidone through the milk should be monitored for side effects as well.
Overall, domperidone is fairly safe when used at recommended dosages, but monitoring your dog and having awareness of potential side effects can help avoid complications. Let your vet know if you have any concerns while your dog is on this medication.