Domperidone

Introduction Overview

Generic Name

domperidone

Brand Name

Motilium, Nauzelin, Domstal, Euciton, Moperidona, Vometa, Zilium and more

Dosage Form

oral tablet, oral suspension, oral drops, orally disintegrating tablet, suppository

Drug Class

dopamine antagonist, antiemetic, prokinetic agent

Pharmacokinetics

Absorption:
Domperidone is rapidly absorbed following oral administration. The oral bioavailability, however, is limited due to extensive first-pass metabolism in the liver, resulting in approximately 15% systemic availability. When taken orally, peak plasma concentrations typically occur within 30 to 60 minutes. Absorption is influenced by food intake; administration before meals is recommended as food delays absorption and reduces peak plasma concentrations slightly but does not affect the overall bioavailability significantly. The orodispersible and liquid formulations facilitate ease of administration, especially in patients with dysphagia or vomiting.

Distribution:
After absorption, domperidone is widely distributed throughout the body but has minimal penetration into the central nervous system since it does not cross the blood-brain barrier appreciably. It is approximately 91–93% protein-bound, predominantly to albumin, which influences its volume of distribution and free active drug concentration. The drug concentrates primarily in peripheral tissues such as the gastrointestinal tract where its primary site of action is located. Domperidone does not accumulate significantly after multiple doses in patients with normal hepatic and renal function.

Metabolism:
Domperidone undergoes extensive hepatic metabolism mainly via the cytochrome P450 enzyme CYP3A4 isoform. Metabolic pathways include hydroxylation and N-dealkylation of the parent compound, leading to less active or inactive metabolites. The first-pass metabolism accounts for significant reduction in systemic bioavailability, and concomitant administration of CYP3A4 inhibitors can increase plasma domperidone concentrations, thereby heightening the risk of adverse cardiac events. The metabolic rate may be reduced in patients with hepatic impairment, necessitating dose adjustments.

Elimination:
Domperidone is primarily eliminated via fecal excretion of metabolites, with approximately 75% excreted in bile and feces and about 20% excreted in the urine as unchanged drug and metabolites. The plasma elimination half-life ranges from 7 to 12 hours, supporting dosing regimens commonly of three times daily administration. Renal impairment has limited impact on domperidone elimination, but caution is advised in severe impaired patients. The drug’s clearance is influenced by hepatic function, as liver disease may decrease metabolic clearance and prolong half-life. Due to potential for QT interval prolongation, elimination kinetics are crucial in assessment of dose and frequency, especially in at-risk populations.

Dosage Forms

Available Dosage Forms:
Domperidone is available in multiple oral and rectal dosage forms, catering to different patient needs. These include:
- Oral tablets: 10 mg strength
- Oral suspension: 160 mg/5 mL formulation
- Oral drops: liquid formulations suitable for infants and adults
- Orally disintegrating tablets (orodispersible tablets): 10 mg
- Suppositories: 30 mg

Dosages for Adults and Adolescents:
Recommended dosages depend on the indication but generally are within the following ranges:
- Tablets and oral suspension: 10 mg taken up to three times daily, ideally 15 to 30 minutes before meals to optimize absorption; the typical maximum dose is 30 mg per day, though some cases permit up to 40 mg daily under strict medical supervision.
- Suppositories: 30 mg administered twice daily, with a maximum of two suppositories per day.
Treatment duration is usually limited to a maximum of 7 days for gastrointestinal symptoms such as nausea and vomiting, with longer courses requiring careful clinical assessment.

Specific Patient Populations:
- Adolescents and adults weighing 35 kg or more can follow standard dosing regimens.
- Pediatric use (children below 12 years or below 35 kg) is generally not recommended due to safety concerns.
- Hepatic impairment necessitates caution or contraindicates use, depending on severity.
- Renal impairment does not require dose adjustment typically but prolonged treatment should be monitored clinically.
- Elderly patients (>60 years) should be treated with the lowest effective dose due to increased cardiac risk.
- Pregnant and breastfeeding women should only use domperidone with a clear medical indication due to limited safety data and potential side effects in neonates.

This comprehensive array of dosage forms and dosing guidelines allows for tailored treatment approaches matching patient age, weight, tolerance, and clinical need.

Mechanism Of Action

Domperidone is primarily a peripheral dopamine D2 and D3 receptor antagonist which exerts its pharmacological effects predominantly outside the blood-brain barrier. It works by blocking dopamine receptors in the gastrointestinal tract, promoting increased motility by enhancing acetylcholine release from enteric neurons. This results in accelerated gastric emptying and improved transit through the upper GI tract, effectively alleviating symptoms caused by delayed gastric emptying such as nausea, vomiting, and bloating.

Additionally, domperidone antagonizes dopamine receptors in the chemoreceptor trigger zone (CTZ) of the brain, located outside the blood-brain barrier, which is implicated in the neural pathways of nausea and vomiting. By blocking dopamine-mediated pathways here, domperidone effectively reduces the stimulation of vomiting reflexes, making it a potent antiemetic agent.

Unlike other dopamine antagonists such as metoclopramide, domperidone does not readily cross the blood-brain barrier, thereby minimizing central nervous system side effects such as extrapyramidal symptoms and sedation. This peripheral selectivity gives it a more favorable safety profile in terms of cognitive and motor side effects.

In lactating women, domperidone increases serum prolactin levels by inhibiting dopamine's suppressive effect on the anterior pituitary lactotrophs, promoting breast milk production. This endocrinological effect is a basis for its off-label use as a galactagogue, although clinical evidence and safety considerations necessitate cautious use.

Clinical studies confirm domperidone’s efficacy in improving gastric motility and treating emesis associated with various causes including migraine, post-operative nausea, and adverse drug reactions. Comparative pharmacodynamic data highlight its advantage over other dopamine antagonists due to its peripheral action and reduced CNS penetration.

Pharmacological Actions

Peripheral dopamine D2 and D3 receptor antagonism leading to increased gastrointestinal motility
Acceleration of gastric emptying and enhanced upper gastrointestinal tract transit
Antiemetic effect via blockade of dopamine receptors in the chemoreceptor trigger zone outside the blood-brain barrier
Augmentation of prolactin secretion via antagonism of pituitary dopamine receptors, enhancing lactation
Reduced central nervous system penetration compared to other dopamine antagonists, minimizing extrapyramidal side effects
Promotion of acetylcholine release in enteric neurons facilitating smooth muscle contractions in the GI tract
Inhibition of dopamine-mediated nausea and vomiting pathways without causing sedation
Use as a prokinetic agent in conditions such as gastroparesis to improve symptomatic control
Potential minor effect on cardiac ion channels contributing to QT interval prolongation risk
Minimal anticholinergic activity, preserving motility without typical anticholinergic side effects
Interaction with CYP3A4 metabolic pathways influencing plasma levels and pharmacodynamics
Dopamine receptor blockade contributing to its efficacy in prevention of drug-induced nausea, especially with Parkinson’s disease medications
Limited psychotropic activity due to peripheral selectivity, distinguishing from centrally acting neuroleptics
Modest influence on gastrointestinal hormones secondary to dopaminergic modulation

Therapeutic Or Clinical Uses

Treatment of nausea and vomiting from various etiologies including migraine, gastrointestinal disorders, and drug-induced causes
Management of gastroparesis and other conditions associated with delayed gastric emptying
Enhancement of gastric motility to relieve symptoms such as bloating, early satiety, and upper abdominal discomfort
Adjunct therapy to prevent nausea and vomiting induced by antiparkinsonian drugs such as levodopa and pergolide
Off-label use to stimulate breast milk production (galactagogue effect) via prolactin elevation
Symptomatic relief in functional dyspepsia with impaired gastric motility
Used in patients intolerant to other dopamine antagonists due to lower CNS side effect profile
Prevention of postoperative and chemotherapy-induced nausea and vomiting in certain jurisdictions
Treatment of gastrointestinal motility disorders where enhanced propulsive activity is required
Supportive therapy in patients with chronic conditions causing upper gastrointestinal hypomotility

Side Or Adverse Effects

Dry mouth, a common anticholinergic-like side effect
Uncontrolled extrapyramidal movements including irregular eye and tongue movements, dystonia, particularly in children
Headaches and dizziness
Lowered libido and sexual dysfunction in men
Anxiety, agitation, irritability, and nervousness
Diarrhea and other mild gastrointestinal disturbances
Skin reactions such as itching, rash, urticaria, and hypersensitivity reactions
Unusual breast milk production or galactorrhea, including breast tenderness and enlargement in men and women
Menstrual irregularities or amenorrhea in women
Cardiovascular side effects including arrhythmias, palpitations, and prolonged QT interval with risk of severe cardiac dysrhythmias or sudden cardiac arrest especially at doses above 30 mg/day or in elderly patients
Rare seizures or convulsions
Fatigue and a general feeling of weakness
Abnormal liver function tests indicative of hepatic effect
Signs of allergic reaction including swelling of the face, lips, throat, and difficulty breathing
Hypersensitivity reactions and angioedema requiring immediate medical attention

Precautions

Use with caution in patients over 60 years due to increased risk of cardiac arrhythmias
Avoid use in patients with known prolonged QT interval or significant cardiac conduction abnormalities
Do not use in patients with moderate or severe hepatic impairment
Monitor electrolyte levels, especially potassium and magnesium, before and during therapy as imbalances increase cardiac risk
Avoid concomitant use with potent CYP3A4 inhibitors (e.g., ketoconazole, erythromycin) that increase domperidone plasma levels
Caution in patients with renal impairment during prolonged use; dosage adjustment may be needed
Not recommended during pregnancy unless the benefits outweigh potential risks; limited safety data available
Should be used during breastfeeding only if clearly necessary due to potential effects on breastfed infants
Patients should be monitored for signs of extrapyramidal symptoms, especially pediatric populations
Avoid use in patients with prolactin-secreting pituitary tumors (prolactinoma)
Use contraindicated in cases of intestinal obstruction, perforation, or gastrointestinal hemorrhage
Careful assessment required for patients on drugs that prolong QT interval
Stop treatment and seek urgent medical advice if cardiac symptoms such as palpitations or syncope occur
Short-term use recommended, generally not exceeding 7 days for nausea and vomiting unless supervised by a physician
Advise patients to report allergic reactions or neurological symptoms promptly

Warnings

Increased risk of serious cardiac events including QT interval prolongation, torsades de pointes, and sudden cardiac death, especially with doses >30 mg/day or in elderly
Do not use in patients with known hypersensitivity to domperidone or any excipients
Contraindicated in pituitary tumors that secrete prolactin (prolactinoma) as domperidone increases prolactin levels
Avoid use during pregnancy and breastfeeding unless specifically advised by a healthcare professional
Concomitant use with medications that prolong QT interval or inhibit CYP3A4 may increase risk of cardiac adverse events
Risk of extrapyramidal reactions especially in children and at higher doses
Use with caution in patients with electrolyte disturbances (hypokalemia, hypomagnesemia) as they exacerbate cardiac risk
Do not exceed recommended doses or duration of therapy; overdosing increases risk of CNS and cardiac toxicity
Treatment should be discontinued if cardiac symptoms, seizures, or severe allergic reactions develop
Patients with severe liver disease should not be treated with domperidone
Use caution in patients with heart failure or existing cardiac conduction abnormalities
Use only under medical supervision with appropriate cardiac monitoring in high-risk patients
Patients should be instructed to seek emergency care if they experience signs of angioedema or difficulty breathing
Avoid use in patients with gastrointestinal bleeding, obstruction, or perforation
Monitoring of liver function tests is advisable during prolonged therapy

Contraindication

Hypersensitivity to domperidone or any formulation excipients
Presence of prolactinoma (pituitary gland tumors secreting prolactin)
Known or suspected gastrointestinal obstruction, perforation, or hemorrhage
Moderate to severe hepatic impairment or liver failure
Patients with cardiac conditions that prolong QT interval or known arrhythmias
Heart failure or severe cardiac insufficiency
Electrolyte imbalances including hypokalemia, hypomagnesemia, or hyperkalemia predisposing to arrhythmias
Concomitant use with potent CYP3A4 inhibitors such as ketoconazole, clarithromycin, erythromycin, and protease inhibitors
Concomitant use with other QT-prolonging drugs such as amiodarone, sotalol, haloperidol, cisapride, or citalopram
Past history of cardiac arrest or known risk factors for sudden cardiac death
Children under 12 years and adolescents weighing less than 35 kg (lack of safety and efficacy data)
Pregnancy unless justified by therapeutic need and risk-benefit assessment
Breastfeeding women unless benefits outweigh risks as determined by clinician

Drug Interactions

Potent CYP3A4 inhibitors (e.g., ketoconazole, fluconazole, itraconazole, erythromycin, clarithromycin) increase domperidone plasma concentrations and risk of cardiac arrhythmias
Antiarrhythmic agents (amiodarone, sotalol, quinidine, disopyramide) may potentiate QT prolongation when co-administered
Certain antipsychotics (haloperidol, pimozide, sertindole) may have additive effects on QT interval and dopaminergic pathways
Selective serotonin reuptake inhibitors such as citalopram and escitalopram can predispose to QT prolongation when combined
Gastrointestinal prokinetics and antiemetics like cisapride, dolasetron, prucalopride have overlapping toxicities and cardiac risks
Protease inhibitors used in AIDS/HIV (e.g., ritonavir, indinavir) inhibit CYP3A4 and increase domperidone levels
Some antibiotics including telithromycin, moxifloxacin, pentamidine increase cardiac risk when combined
Medications used in malaria treatment such as halofantrine contraindicated due to arrhythmogenic potential
Certain antihistamines (mequitazine, mizolastine) may affect QT interval when coadministered
Apomorphine administration requires prior tolerance testing when used with domperidone due to additive pharmacodynamic effects
Oral contraceptives and other drugs affecting prolactin secretion may interact with domperidone's endocrine effects
Drug combinations that cause electrolyte disturbances increase risks associated with domperidone
Consult healthcare provider prior to co-administration of any new medications, including over-the-counter and herbal supplements
Domperidone may interfere with absorption or efficacy of other GI motility agents
Serious cardiac adverse events reported with interacting drugs necessitate ECG monitoring during combination therapy

Preparations Of The Drug

Motilium tablets containing 10 mg domperidone – formulated with lactose, maize starch, microcrystalline cellulose, pregelatinized potato starch, povidone, magnesium stearate, hydrogenated cottonseed oil, sodium lauryl sulfate, hypromellose
Motilium oral suspension (Zentiva brand) including sorbitol, microcrystalline cellulose, carmellose sodium, methyl-p-hydroxybenzoate, propylhydroxybenzoate, sodium saccharin, polysorbate 20, sodium hydroxide, purified water
Motilium suppositories containing 30 mg domperidone – formulated with tartaric acid, macrogol 4000, macrogol 1000, macrogol 400, butyl hydroxyanisol as a preservative
Domstal baby drops suitable for pediatric use with adjusted concentrations and appropriate excipients for tolerability
Orally disintegrating tablets (orodispersible) that dissolve rapidly in the mouth for patients with swallowing difficulties
Generic versions manufactured by multiple pharmaceutical companies including Janssen-Cilag, Zentiva Pharma, and others
Available in multiple country-specific branded and generic formulations tailored for regional regulatory approvals
Dosage forms designed to optimize administration routes including rectal suppositories for patients unable to take oral medications
Specialized suspension and drop formulations facilitating accurate dosing in infants and children
Packaging often includes dosing aids such as measuring cups and droppers to ensure precise dose administration
Stable at room temperature within 20-25°C, protected from light, with specific storage conditions for suppositories to prevent melting
Excipients carefully selected to improve drug stability, palatability, and patient compliance
Product labeling advises on contraindications, dosage adjustments, and monitoring requirements per formulation