MAXOLON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MAXOLON (MAXOLON).
Metoclopramide, the active ingredient in MAXOLON, is a dopamine D2 receptor antagonist and also enhances the response to acetylcholine at muscarinic receptors in the gastrointestinal tract, leading to increased gastric motility and accelerated gastric emptying. It also has antiemetic effects by blocking dopamine receptors in the chemoreceptor trigger zone (CTZ).
| Metabolism | Metoclopramide is metabolized primarily via the liver by oxidation (CYP2D6, CYP3A4) and conjugation. It has a half-life of approximately 4-6 hours. |
| Excretion | Renal: 85-95% as unchanged drug and metabolites; biliary/fecal: <5%. |
| Half-life | 5-6 hours in adults with normal renal function; prolonged to 15-20 hours in severe renal impairment (CrCl <10 mL/min). |
| Protein binding | 13-30% primarily to albumin. |
| Volume of Distribution | 3-5 L/kg; extensive tissue distribution. |
| Bioavailability | Oral: 60-85%; IM: 75-100%. |
| Onset of Action | Oral: 30-60 minutes; IV: 1-3 minutes; IM: 10-15 minutes. |
| Duration of Action | Oral: 3-4 hours; IV/IM: 1-2 hours; clinical effects on gastric motility may persist longer. |
10 mg orally, intramuscularly, or intravenously three to four times daily. Maximum daily dose: 30 mg or 0.5 mg/kg.
| Dosage form | TABLET |
| Renal impairment | GFR 10-60 mL/min: reduce dose to 50% of normal. GFR <10 mL/min: administer 25% of normal dose. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B or C: use 50% of standard dose with caution. |
| Pediatric use | 0.1-0.2 mg/kg per dose intravenously, intramuscularly, or orally every 6-8 hours. Maximum single dose: 10 mg. |
| Geriatric use | Initiate at 5 mg every 8-12 hours. Titrate cautiously due to increased risk of extrapyramidal symptoms and sedation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MAXOLON (MAXOLON).
| Breastfeeding | Metoclopramide is excreted into human breast milk. The milk-to-plasma ratio (M/P) is approximately 1.0 to 2.6. Relative infant dose is estimated at 6-24% of the maternal weight-adjusted dose. Although considered compatible with breastfeeding by the American Academy of Pediatrics, monitor the infant for potential extrapyramidal symptoms and gastrointestinal disturbances. |
| Teratogenic Risk | Metoclopramide (MAXOLON) is classified as FDA Pregnancy Category B. In the first trimester, data from large cohort studies do not indicate a significant increase in major congenital malformations. However, a slight increase in the risk of fetal neural tube defects has been suggested in some studies, but not confirmed. In the second and third trimesters, chronic use may cause maternal extrapyramidal symptoms and has been associated with fetal methemoglobinemia. Near term, use may cause neonatal extrapyramidal symptoms, including dystonias, if administered shortly before delivery. |
■ FDA Black Box Warning
Tardive dyskinesia (TD) may develop with prolonged or high-dose use, especially in elderly patients. Risk increases with cumulative dose and treatment duration. Avoid use in patients requiring long-term treatment (>12 weeks). Discontinue if signs/symptoms of TD appear.
| Serious Effects |
Hypersensitivity to metoclopramide; history of tardive dyskinesia; history of epilepsy or movement disorders; gastrointestinal hemorrhage, obstruction, or perforation; pheochromocytoma; concurrent use of drugs that may cause EPS; risk of methemoglobinemia (e.g., G6PD deficiency).
| Precautions | May cause extrapyramidal symptoms (EPS), especially in children and young adults; tardive dyskinesia with long-term use; neuroleptic malignant syndrome (rare); depression; hypertension; fluid retention (with high doses); caution in patients with Parkinson's disease, history of seizure, or concurrent use of CNS depressants. |
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| Fetal Monitoring | Maternal monitoring: Assess for extrapyramidal symptoms (dystonia, parkinsonism), tardive dyskinesia, neuroleptic malignant syndrome; monitor blood pressure (may cause hypotension); serum prolactin levels if galactorrhea or menstrual irregularities occur; renal function in dosing adjustments. Fetal monitoring: If used near term, observe neonate for extrapyramidal signs, and for methemoglobinemia (pulse oximetry, co-oximetry if symptoms). |
| Fertility Effects | Metoclopramide can cause hyperprolactinemia due to dopamine D2 receptor antagonism in the pituitary, leading to galactorrhea, menstrual irregularities, and potentially reversible infertility. This effect is dose-dependent and typically resolves upon discontinuation. In men, gynecomastia and erectile dysfunction may occur. No specific effects on gamete quality or long-term reproductive function are established. |