Indications
- Gastric Bezoar
- Gastroesophageal Reflux Disease (GERD) (see Gastroesophageal Reflux Disease, Gastroesophageal Reflux Disease)
- Gastroparesis (see Gastroparesis, Gastroparesis)
- Hiccups (see Hiccups, Hiccups)
- Lactation Stimulant
- Migraines (see Migraines, Migraines)
- Nausea/Vomiting (see Nausea and Vomiting, Nausea and Vomiting)
- Tourette Syndrome (see Tourette Syndrome, Tourette Syndrome)
- Vascular Headaches
Pharmacology
- Dopamine D2 Receptor Antagonist (see Dopamine Receptor Antagonists, Dopamine Receptor Antagonists): at low dose
- Central Dopamine D2 Receptors: located in the central nervous system chemoreceptor trigger zone
- Peripheral Dopamine D2 Receptors
- Mixed Serotonin 5-HT3 Receptor Antagonist and Serotonin 5-HT4 Receptor Agonist (see Serotonin 5-HT3 Receptor Antagonists, Serotonin 5-HT3 Receptor Antagonists): at high dose
- Enhances Acetylcholine Release and Stimulates Cholinergic Receptors on Gastric Smooth Muscle
Physiologic Effects
- Antiemetic Effect
- Mediated by antagonism at dopamine D2 receptors in the chemoreceptor trigger zone of the central nervous system
- May alse be mediated by antagonism at the 5-HT3 receptor when used at higher doses
- Gastroprokinetic Effect: may contribute to the antiemetic effect
- Mediated by muscarinic activity, dopamine D2 receptor antagonist activity, and 5-HT4 receptor agonist activity
- Increased Lower Esophageal Sphincter Tone
Metabolism
- Renal: 85% of oral dose appears in the urine within 72 hrs (50% is present as free or conjugated metoclopramide)
- Half-Life: 5-6 hrs
Administration
- PO: 5-10 mg q6hrs
- Onset: 30-60 min
- Duration: 1-2 hrs
- IV: 5-10 mg q6hrs
- Onset: 1-3 min
- Duration: 1-2 hrs
Dose Adjustment
- Hepatic: none
- Renal: decrease initial dose by 50% in patients with CrCl <40 mL/min
Use in Pregnancy (see Pregnancy, Pregnancy)
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Drug Interactions
- Monoamine Oxidase (MAO) Inhibitors (see Monoamine Oxidase Inhibitors, Monoamine Oxidase Inhibitors)
- Metoclopramide Increases Catecholamines, Potentiating the Hypertensive Effects of MAO Inhibitors
- Serotonin Reuptake Inhibitors (see Selective Serotonin Reuptake Inhibitors, Selective Serotonin Reuptake Inhibitors and Serotonin-Norepinephrine Reuptake Inhibitors, Serotonin-Norepinephrine Reuptake Inhibitors)
- Concomitant Use of Metoclopramide with Serotonin Reuptake Inhibitors May Increase Metoclopramide Levels and the Risk of Adverse Effects
- Metoclopramide Possibly Increases the Risk of Serotonin Syndrome (see Serotonin Syndrome, Serotonin Syndrome)
- Sedatives
- Metoclopramide Potentiates Effects of Other Sedatives
- Succinylcholine (see Succinylcholine, Succinylcholine)
- Metoclopramide Inhibits Plasma Cholinesterase, Prolonging the Effect of Succinylcholine
Adverse Effects
Cardiovascular Adverse Effects
- Atrioventricular Block
- First Degree Atrioventricular Block (see First Degree Atrioventricular Block, First Degree Atrioventricular Block)
- Second Degree Atrioventricular Block-Mobitz Type I (Wenckebach) (see Second Degree Atrioventricular Block-Mobitz Type I, Second Degree Atrioventricular Block-Mobitz Type I)
- Second Degree Atrioventricular Block-Mobitz Type II (see Second Degree Atrioventricular Block-Mobitz Type II, Second Degree Atrioventricular Block-Mobitz Type II)
- Third Degree Atrioventricular Block (see Third Degree Atrioventricular Block, Third Degree Atrioventricular Block)
- Congestive Heart Failure (CHF) (see Congestive Heart Failure, Congestive Heart Failure)
- Physiology: due to increased aldosterone secretion, resulting in fluid retention
- Hypertension (see Hypertension, Hypertension)
- Hypotension (see Hypotension, Hypotension)
- Sinus Bradycardia (see Sinus Bradycardia, Sinus Bradycardia)
Dermatologic Adverse Effects
Endocrine Adverse Effects
- Galactorrhea (see Galactorrhea, Galactorrhea): due to hyperprolactinemia
- Gynecomastia (see Gynecomastia, Gynecomastia)
Gastrointestinal Adverse Effects
Hematologic Adverse Effects
- Leukopenia/Neutropenia (see Leukopenia, Leukopenia and Neutropenia, Neutropenia)
Neurologic Adverse Effects
- Delirium/Confusion (see Delirium, Delirium)
- Depression (see Depression, Depression)
- Drowsiness/Lethargy/Obtundation (see Obtundation-Coma, Obtundation-Coma)
- Extrapyramidal Symptoms (see Extrapyramidal Symptoms, Extrapyramidal Symptoms)
- Akathisia (see Akathisia, Akathisia): motor restlessness
- Dystonia (see Dystonia, Dystonia): continuous spasms and muscle contractions
- Tardive Dyskinesia (see Tardive Dyskinesia, Tardive Dyskinesia): irregular, jerky movements
- Parkinsonism (see Parkinson’s Disease, Parkinsons Disease): cogwheel rigidity, bradykinesia, tremor, mask-like facies
Renal Adverse Effects
- Green Urine (see Urine Discoloration, Urine Discoloration)
Toxicologic Adverse Effects
- Methemoglobinemia (see Methemoglobinemia, Methemoglobinemia)
- Sulfhemoglobinemia (see Sulfhemoglobinemia, Sulfhemoglobinemia)
Other Adverse Effects
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References
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