Domaid5 mg/5 ml

Domaid 5 mg/5 ml is a peripherally acting dopamine antagonist and prokinetic agent indicated for the symptomatic relief of a range of upper gastrointestinal motility disorders and nausea and vomiting of various causes.

Dyspeptic Symptom Complex

Domperidone is indicated for the management of functional dyspepsia and dyspeptic symptoms frequently associated with delayed gastric emptying, gastroesophageal reflux (GERD), and esophagitis, including:

• Epigastric sense of fullness — uncomfortable feeling of heaviness or pressure in the upper abdomen after eating
• Feeling of abdominal distension — bloating and abdominal swelling
• Upper abdominal pain — discomfort or pain in the epigastric region
• Eructation (belching) — repeated involuntary belching due to excess gas
• Flatulence — excess gas in the gastrointestinal tract
• Early satiety — feeling of fullness after eating only a small amount of food (a hallmark of gastroparesis)
• Nausea and vomiting associated with dyspepsia
• Heartburn with or without regurgitation of gastric contents into the mouth
• Non-ulcer dyspepsia — functional dyspepsia in the absence of a structural cause

Acute Nausea and Vomiting

Domperidone is indicated for the symptomatic relief of acute nausea and vomiting arising from a wide variety of causes, including:

• Functional origin — nausea related to gastrointestinal dysmotility
• Organic origin — nausea due to systemic or organic disease
• Infectious origin — nausea and vomiting associated with gastroenteritis and other infections
• Dietetic origin — nausea from dietary indiscretion or food intolerance
• Drug-induced nausea and vomiting — including that associated with dopaminergic medications
• Radiotherapy-induced nausea and vomiting
• Migraine-associated nausea and vomiting — Domperidone can also improve the absorption of oral antimigraine medications by accelerating gastric emptying during migraine attacks

Parkinson's Disease

Domperidone is specifically indicated in Parkinson's disease patients for the management of nausea and vomiting induced by dopamine agonists (e.g., levodopa, bromocriptine, ropinirole, pramipexole, apomorphine). Because Domperidone does not cross the blood-brain barrier at therapeutic doses, it effectively counteracts the peripheral gastrointestinal side effects of dopaminergic therapy without blocking the central therapeutic effects of these drugs on motor function.

Radiological Studies

Domperidone can be used to speed barium transit during follow-through radiological studies of the gastrointestinal tract, improving the quality and efficiency of these diagnostic procedures.

Prokinetic Drugs / Motility Stimulants / Dopamine Antagonists (Antiemetics)

Domaid 5 mg/5 ml is a benzimidazole derivative and selective dopamine D2/D3 receptor antagonist with both antiemetic and gastric prokinetic properties. Its unique pharmacological profile — peripheral action with minimal CNS penetration — distinguishes it from other dopamine antagonist antiemetics such as metoclopramide and prochlorperazine.

Mechanism of Action

Domperidone exerts its effects by blocking dopamine D2 and D3 receptors at two key anatomical sites:

1. Chemoreceptor Trigger Zone (CTZ) — Antiemetic Effect

The CTZ is located in the area postrema of the brain, which lies outside the blood-brain barrier. Domperidone reaches the CTZ and blocks dopamine receptors there, preventing the dopamine-mediated stimulation of the vomiting centre. This produces its potent antiemetic (anti-nausea/anti-vomiting) effect — without significantly penetrating the rest of the brain.

2. Gastrointestinal Tract — Gastroprokinetic Effect

Dopamine normally inhibits gastrointestinal motility by acting on D2 receptors in the gut wall. By blocking these peripheral dopamine receptors, Domperidone produces coordinated improvements in upper GI tract motility, specifically:

• Restores normal motility and tone of the upper gastrointestinal tract
• Facilitates and accelerates gastric emptying — reducing the time food spends in the stomach
• Enhances antral and duodenal peristalsis — improving the coordinated muscular contractions that move food from the stomach into the small intestine
• Regulates pyloric contraction — normalizing the coordinated opening and closing of the pyloric sphincter
• Increases esophageal peristalsis — improving clearance of refluxed material from the esophagus
• Increases lower esophageal sphincter (LES) pressure — reducing the backward flow of stomach acid into the esophagus, thereby preventing gastroesophageal reflux and regurgitation

Blood-Brain Barrier Selectivity — Key Safety Advantage

Domperidone's most important pharmacological distinction is its very weak penetration across the intact blood-brain barrier. Unlike metoclopramide, which readily crosses into the CNS and blocks striatal D2 receptors, Domperidone remains largely in the peripheral circulation at therapeutic doses. As a result:

• It produces virtually no CNS dopaminergic blockade at therapeutic doses in adults with an intact blood-brain barrier
• It causes no psychotropic (sedation, anxiety, depression) or extrapyramidal side effects (Parkinsonism, akathisia, tardive dyskinesia) in adults under normal conditions
• It does not interfere with the central therapeutic effects of dopaminergic medications used in Parkinson's disease

Important exception: In neonates and young infants (under 1 year), the blood-brain barrier is not fully matured, and in patients with disrupted blood-brain barrier integrity (head injury, meningitis, stroke), neurological effects of Domperidone cannot be entirely excluded.

Prolactin Release

Because the pituitary gland is located outside the blood-brain barrier, Domperidone can access the pituitary lactotroph cells and block dopamine's inhibitory effect on prolactin secretion. This results in elevated prolactin levels (hyperprolactinaemia), which is relevant both as a potential side effect and as a clinical use — Domperidone is sometimes used off-label to promote lactation (galactorrhoea) in breastfeeding mothers with insufficient milk supply.

Pharmacokinetics

• Absorption: Rapidly absorbed from the GI tract after oral administration. Oral bioavailability is approximately 15% due to significant first-pass hepatic metabolism. Taking Domperidone 15–30 minutes before meals significantly enhances bioavailability (peak plasma concentrations approximately 15–30 minutes before meals are 60% higher than when taken after meals).
• Peak plasma concentration (C_max): Reached within approximately 30 minutes after an oral dose.
• Distribution: Widely distributed in body tissues. Low plasma protein binding (approximately 90%). Volume of distribution is large (approximately 5.7 L/kg), indicating extensive tissue binding.
• Metabolism: Extensively metabolized in the liver via CYP3A4 (the major pathway) and also via CYP1A2 and CYP2E1. This extensive first-pass metabolism explains the low oral bioavailability.
• Half-life: Approximately 7 to 8 hours in healthy adults with normal hepatic and renal function. Prolonged to approximately 20.8 hours in patients with severe renal insufficiency.
• Elimination: Excreted primarily via feces (approximately 66% as metabolites) and to a lesser extent in urine (approximately 31%). Only a very small fraction of unchanged drug is excreted in the urine.

Oral Tablets (Standard and Dispersible)

• Take Domperidone tablets 15 to 30 minutes before meals. This pre-meal timing is essential — bioavailability is significantly higher when taken in the fasted state before eating compared to after meals.
• If a bedtime dose is required (for nocturnal reflux or nausea), take it before retiring.
• Swallow standard tablets whole with a full glass of water.
• Dispersible/Meltab tablets: Place on the tongue and allow to dissolve before swallowing with saliva or a sip of water — no chewing required. This formulation is particularly convenient for patients who have difficulty swallowing tablets.
• Do not take antacids or antisecretory drugs (e.g., H2 blockers, PPIs) at exactly the same time as Domperidone, as these reduce Domperidone's oral bioavailability (see Drug Interactions).

Oral Suspension

• Shake the bottle well before each use.
• Measure each dose using the measuring spoon or oral syringe provided. Do not use a regular household teaspoon.
• Administer 15 to 30 minutes before meals.
• The oral suspension is particularly suitable for children who cannot swallow tablets and for adults who prefer liquid formulation.
• Store the opened bottle as directed on the label (typically at room temperature below 30°C) and use within the stated shelf-life after opening.

Paediatric Drops

• Use only the calibrated dropper supplied with the product. Each 1 ml delivers 5 mg of Domperidone.
• Administer the correct weight-based dose 15 to 30 minutes before each meal.
• The drops can be given directly into the infant's mouth or mixed with a small amount of water, milk, or formula.
• Shake well before each use.

Suppositories (Rectal Administration)

• Suppositories are indicated when oral administration is not possible — for example, in patients with severe vomiting who cannot retain oral medication.
• Wash hands thoroughly before and after insertion.
• If the suppository is too soft at room temperature, refrigerate briefly (10–15 minutes) before use.
• Remove the foil wrapper and insert the suppository, pointed end first, gently into the rectum.
• The patient should remain still for a few minutes after insertion to allow adequate absorption.
• Store suppositories below 25°C — heat may cause them to soften or melt.

Anticholinergic Drugs (Reduced Efficacy)

Anticholinergic drugs (e.g., atropine, hyoscine, dicycloverine) may antagonize the antidyspeptic and gastroprokinetic effects of Domperidone. Acetylcholine is a key neurotransmitter in promoting gastrointestinal motility; anticholinergics reduce GI motility and oppose Domperidone's prokinetic action. Concurrent use should be avoided when the gastroprokinetic effect of Domperidone is the primary treatment goal.

Antacids and Antisecretory Drugs (Reduced Absorption)

Antacids (aluminum/magnesium hydroxide) and antisecretory agents (H2-receptor antagonists such as ranitidine; proton pump inhibitors such as omeprazole) should not be given simultaneously with Domperidone. These agents raise the intragastric pH, which reduces the oral bioavailability of Domperidone (Domperidone dissolves better in acidic conditions). To ensure adequate Domperidone absorption, take Domperidone before meals and separate antacids/antisecretory drugs by at least 2 hours.

CYP3A4 Inhibitors — Clinically Important Interaction

Domperidone is primarily metabolized by the CYP3A4 hepatic enzyme. Drugs that significantly inhibit CYP3A4 reduce Domperidone metabolism, leading to substantially elevated Domperidone plasma concentrations. This is clinically important because elevated Domperidone levels increase the risk of QT interval prolongation and cardiac arrhythmia. CYP3A4 inhibitors that should be used with caution or avoided include:

• Azole antifungals: ketoconazole, itraconazole, fluconazole, voriconazole
• Macrolide antibiotics: erythromycin, clarithromycin
• HIV protease inhibitors: ritonavir, lopinavir, indinavir, saquinavir
• Nefazodone (antidepressant)
• Other potent CYP3A4 inhibitors: amiodarone, aprepitant

Concomitant use of Domperidone with potent CYP3A4 inhibitors that also prolong the QT interval is contraindicated.

QT-Prolonging Drugs

Domperidone itself can prolong the cardiac QTc interval — particularly at higher doses or elevated plasma concentrations. Concomitant use with other drugs that prolong the QT interval (antiarrhythmics, certain antipsychotics, some macrolide antibiotics, fluoroquinolone antibiotics, antimalarials) increases the risk of serious ventricular arrhythmias including torsades de pointes. Avoid combination with other QT-prolonging drugs; if unavoidable, ECG monitoring is essential.

Dopaminergic Agonists (Useful Combination)

Domperidone is specifically recommended in combination with dopamine agonists (e.g., bromocriptine, levodopa, ropinirole, pramipexole, apomorphine) used in Parkinson's disease. Domperidone effectively suppresses the troublesome peripheral side effects of these drugs — particularly nausea, vomiting, and GI discomfort — without counteracting their central motor therapeutic properties. This is because Domperidone does not cross the intact blood-brain barrier and therefore does not antagonize dopamine in the basal ganglia.

Neuroleptics (Antipsychotics)

Domperidone does not potentiate the central effects of neuroleptic drugs (e.g., haloperidol, chlorpromazine). It should not be confused with central dopamine antagonists that exacerbate or add to the antipsychotic or extrapyramidal effects of neuroleptics.

Digoxin and Paracetamol

In patients already stabilized on digoxin or paracetamol (acetaminophen), concomitant administration of Domperidone did not significantly influence the blood levels of these drugs. Clinically significant pharmacokinetic interactions with these drugs are not expected at standard Domperidone doses.

Drugs with Sustained-Release or Enteric-Coated Formulations

Theoretically, since Domperidone accelerates gastric emptying, it could influence the GI absorption rate of co-administered oral drugs — particularly those with sustained-release (extended-release) or enteric-coated formulations. Faster gastric transit may alter the absorption profile of such drugs. Clinical significance varies depending on the specific drug; prescribers should be aware of this potential interaction when initiating Domperidone in patients on sustained-release formulations.

Domperidone is generally well tolerated at recommended doses for short treatment courses. Most adverse effects are rare and dose-dependent. The following adverse effects have been reported:

Gastrointestinal Effects (Rare)

• Transient intestinal cramps — occasionally reported; usually mild and self-limiting
• Dry mouth — reported infrequently
• Diarrhea — rare
• Thirst

Neurological / Extrapyramidal Effects (Rare in Adults, Uncommon in Children)

Because Domperidone has weak blood-brain barrier penetration at therapeutic doses in adults, classical dopamine antagonist-related extrapyramidal reactions are rare. However:

• Extrapyramidal phenomena (acute dystonia, akathisia, pseudo-Parkinsonism) — rare in young children and exceptional in adults with intact blood-brain barriers. These reactions reverse spontaneously and completely as soon as treatment is stopped — no permanent neurological sequelae have been reported.
• In infants under 1 year (in whom the blood-brain barrier is immature) and in patients with blood-brain barrier compromise, neurological side effects cannot be totally excluded and warrant particular caution.
• Headache and dizziness — reported infrequently
• Somnolence (drowsiness) — rare at standard doses

Endocrine / Neuroendocrine Effects

• Hyperprolactinaemia (elevated prolactin levels) — because the pituitary gland lies outside the blood-brain barrier, Domperidone can raise prolactin levels in all patients. In most cases, this is clinically asymptomatic. In rare cases, the following prolactin-mediated effects may occur:
  • Galactorrhoea — spontaneous milk secretion from the breasts (in women and rarely men)
  • Gynaecomastia — breast enlargement in males
  • Breast tenderness or engorgement in women
  • Menstrual irregularities (e.g., amenorrhoea, oligomenorrhoea) with prolonged use
• These effects are generally reversible upon discontinuation of Domperidone.

Cardiac Effects — QT Prolongation (Important Warning)

• QTc interval prolongation — Domperidone has the potential to prolong cardiac repolarization (QTc interval), which can increase the risk of ventricular arrhythmias including torsades de pointes. The risk is greater at higher doses, in patients with existing QT prolongation or cardiac disease, with CYP3A4 inhibitors, and with other QT-prolonging drugs.
• Post-marketing surveillance has identified rare cases of serious ventricular arrhythmias and sudden cardiac death, primarily in patients receiving higher than recommended doses or taking concomitant QT-prolonging drugs. This is the primary reason regulatory authorities have restricted Domperidone to the lowest effective dose for the shortest duration necessary.

Hypersensitivity / Allergic Reactions (Rare)

• Skin rash and urticaria (hives)
• Pruritus (itching)
• Angioedema — rare but reported
• Anaphylaxis — very rare

Pregnancy

Animal studies in which Domperidone was administered at doses up to 160 mg/kg/day — many times the maximum human therapeutic dose — did not produce teratogenic effects or fetal malformations. Human post-marketing data to date have not demonstrated any increase in the risk of birth defects or adverse fetal outcomes at recommended doses.

However, as with most medicinal products, Domperidone should be used during pregnancy only when the anticipated therapeutic benefit clearly justifies the potential risk. Use during the first trimester requires particularly careful justification, as fetal organogenesis occurs during this period. Pregnant women should always consult their physician before taking Domperidone.

Lactation

Domperidone is excreted in human breast milk. Breast milk concentrations are approximately 4 times lower than corresponding maternal plasma concentrations, resulting in low estimated infant exposure. The daily dose received by a breastfed infant is estimated to be well below established thresholds for pharmacological effect in infants.

Nursing is not recommended for mothers taking Domperidone, unless the expected therapeutic benefits to the mother clearly outweigh any potential risk to the nursing infant. If Domperidone is considered essential, breastfeeding may be continued under medical supervision with monitoring of the infant for any adverse effects (particularly extrapyramidal reactions in neonates).

Note: Domperidone is sometimes used off-label at low doses to stimulate or increase breast milk production (galactorrhoea effect via prolactin elevation) in mothers with insufficient lactation. This use is outside the approved indication and should only be undertaken under physician supervision, weighing the limited evidence of efficacy against the cardiac risks.

Effects on Driving and Use of Machinery

Domperidone does not significantly affect mental alertness at therapeutic doses in adults with an intact blood-brain barrier. Patients may drive and operate machinery normally. However, dizziness and drowsiness have been reported rarely — patients should assess their individual response before driving.

Cardiac Risk — QT Prolongation (Critical Warning)

Domperidone may prolong the cardiac QTc interval and increase the risk of ventricular arrhythmias, including potentially fatal torsades de pointes. This risk is amplified by:

• Doses exceeding the recommended maximum (80 mg/day oral)
• Concurrent use of CYP3A4 inhibitors (which increase Domperidone plasma levels)
• Concurrent use of other QT-prolonging drugs
• Pre-existing cardiac disease, congenital QT prolongation, or cardiac arrhythmia
• Electrolyte imbalances (hypokalemia, hypomagnesemia)

Use the lowest effective dose for the shortest necessary duration. Do not exceed 10 mg three times daily (30 mg/day) in adults per current UK/European regulatory guidelines — this is a more conservative recommendation than the MedEx-listed maximum of 80 mg/day, reflecting updated regulatory guidance. Always follow the most current national prescribing guidelines. A baseline ECG should be considered in patients at risk for QT prolongation before initiating Domperidone.

Use in Children — Increased Risk of Extrapyramidal Reactions

Domperidone should be used with absolute caution in children because of an increased risk of extrapyramidal reactions due to an incompletely developed blood-brain barrier. Young children are more susceptible to neurological side effects than adults. Use in children should only be under careful medical supervision, using weight-based dosing and the lowest effective dose.

Use in Infants (Under 1 Year)

In infants under 1 year of age, metabolic and blood-brain barrier functions are not fully developed. Any drug should only be given to infants with great caution and under close medical supervision. The neurological safety advantage of Domperidone over other dopamine antagonists cannot be guaranteed in this age group. Additionally, the risk of cardiac arrhythmias may be greater in very young children. Domperidone is absolutely contraindicated in neonates.

Hepatic Impairment

Since Domperidone undergoes extensive first-pass and systemic metabolism in the liver (primarily via CYP3A4), it should be used with caution in patients with hepatic impairment. Impaired liver function significantly reduces drug clearance, leading to accumulation of Domperidone at higher-than-expected plasma levels, increasing the risk of cardiac and neurological adverse effects. Dose reduction and careful monitoring are required. Domperidone is contraindicated in severe hepatic impairment.

Renal Impairment

In patients with severe renal insufficiency (serum creatinine >6 mg/100 ml, i.e., >0.6 mmol/L), the elimination half-life of Domperidone increases from approximately 7.4 hours to 20.8 hours. Although plasma drug levels may paradoxically be lower (due to altered distribution), the prolonged half-life means accumulation can occur with repeated dosing. For repeated (multiple-dose) administration in patients with severe renal impairment, the dosing frequency should be reduced to once or twice daily, depending on the severity. Regular review of patients on prolonged therapy is recommended.

Duration of Treatment

Domperidone should be used for the shortest effective duration. Prolonged or high-dose use increases the risk of cardiac arrhythmias, hyperprolactinaemia-related side effects, and — in susceptible patients — extrapyramidal reactions. Do not continue treatment beyond 12 weeks for nausea and vomiting without medical reassessment.

Avoid Concurrent QT-Prolonging Drugs

A thorough review of all concurrent medications should be conducted before prescribing Domperidone. Particular attention should be paid to drugs that prolong the QT interval or inhibit CYP3A4. Combination of Domperidone with potent CYP3A4 inhibitors that also prolong the QT interval is contraindicated.

Domperidone has a relatively wide therapeutic margin, but overdose can produce clinically important effects, particularly in children. The following symptoms may occur in the event of Domperidone overdose:

• Drowsiness and sedation
• Disorientation and confusion
• Extrapyramidal reactions — including acute dystonia (sustained or repetitive involuntary muscle contractions, particularly of the neck and face), akathisia (severe restlessness), and pseudo-Parkinsonism (tremor, rigidity, bradykinesia). These are especially likely in children due to their less mature blood-brain barrier, and also in patients with high plasma Domperidone concentrations. These reactions reverse spontaneously once the drug is cleared.
• QT interval prolongation and cardiac arrhythmias — including torsades de pointes; may be life-threatening in severe overdose

Management of Overdose

There is no specific antidote for Domperidone overdose. Treatment is symptomatic and supportive:

• Activated charcoal — administration is recommended as soon as possible after overdose in a patient who can protect their airway, to reduce further drug absorption
• Close clinical observation — monitor vital signs, cardiac rhythm (ECG for QT prolongation), and neurological status
• Extrapyramidal reactions: Can be controlled with anticholinergic drugs (e.g., biperiden, benztropine), antiparkinson drugs, or antihistamines with anticholinergic properties (e.g., promethazine, diphenhydramine). These agents help counteract the dopamine-blocking effects on motor pathways.
• Cardiac monitoring: Continuous ECG monitoring is advisable in significant overdose cases. Hypokalemia and hypomagnesemia (which worsen QT prolongation) should be corrected promptly with electrolyte replacement.

In the event of suspected Domperidone overdose, contact a poison control center or seek emergency medical care immediately.

• Store tablets, suspension, and paediatric drops below 30°C, protected from light and moisture.
• Keep all formulations out of the reach of children.
• Do not use any formulation after the expiry date printed on the label or packaging.
• Oral suspension (after opening): Store at room temperature below 30°C, protected from light. Use within the period stated on the label after first opening (typically 30 days). Shake well before each use.
• Suppositories: Store below 25°C. High ambient temperatures may cause suppositories to soften — store in a cool location or refrigerate briefly before use if softening occurs. Do not freeze.
• Store in original packaging to protect from light and humidity.
• Effervescent granule sachets: Store in a cool, dry place in their sealed sachets. Do not store opened sachets. Prepare and consume immediately after dissolving in water.

Infants (Under 1 Year)

Domperidone is contraindicated in neonates. In infants under 1 year of age, the metabolic and blood-brain barrier functions are not fully developed. Since the neurological safety profile of Domperidone in adults depends on poor blood-brain barrier penetration, this advantage cannot be fully relied upon in very young infants. The possible occurrence of extrapyramidal and other neurological effects cannot be totally excluded in this age group. Any use in infants under 1 year should only be considered under strict medical supervision when the benefit clearly outweighs the risk, using weight-based dosing and the lowest effective dose.

Pediatric Patients (Over 1 Year)

Domperidone may be used in children over 1 year of age with weight-based dosing (0.2–0.4 mg/kg per dose, every 6–8 hours). Extra caution is required because younger children have a less fully developed blood-brain barrier and are more susceptible to extrapyramidal reactions than adults. Use should be under medical supervision at the lowest effective dose.

Elderly Patients

No specific dose adjustment is required for elderly patients based on age alone. However, elderly patients are more likely to have underlying cardiac disease, reduced renal or hepatic function, electrolyte imbalances, and polypharmacy — all of which increase the risk of QT prolongation and arrhythmias. Careful assessment of cardiac risk factors before prescribing and use of the lowest effective dose is particularly important in elderly patients.

Patients with Hepatic Impairment

Since Domperidone is highly metabolized in the liver, it should be used with caution in patients with mild to moderate hepatic impairment. Domperidone is contraindicated in patients with severe hepatic impairment. In mild to moderate impairment, dose reduction should be considered and liver function monitored during therapy.

Patients with Renal Impairment

For single acute administration, dose adjustment is unlikely to be necessary in patients with renal insufficiency. For repeated multiple-dose administration, the dosing frequency should be reduced based on severity:

• Mild renal impairment: Normal dosing may be maintained with monitoring
• Moderate renal impairment: Reduce dosing frequency to once or twice daily
• Severe renal impairment (creatinine >6 mg/100 ml): Dose once daily only, under close monitoring

Patients on prolonged Domperidone therapy — particularly those with renal impairment — should be reviewed regularly by their physician.