Metoclopramide

(metoclopramide hydrochloride monohydrate)

Brand

Reglan

Availability

Tablets: 5 mg, 10 mg
Suspension: 0.4 mg/ml to 10 mg/ml

Pharmacology

Metoclopramide, a derivative of para-aminobenzoic acid, is a promotility agent. It sensitizes the smooth muscles of the gastrointestinal tract including the muscles of the lower esophageal sphincter, stomach, and small intestine by interacting with receptors for acetylcholine and dopamine on gastrointestinal muscles and nerves.

Metoclopramide relieves gastric stasis by reducing the emptying time of the stomach, and is believed to decrease regurgitation into the esophagus. It reduces nausea, and in those animals (excluding rats) that have the ability to vomit it acts as an antiemetic. It does not stimulate gastric, pancreatic or biliary secretions.

Metoclopramide increases peristalsis of the small intestine, possibly speeding small intestine transit times, but has little effect on the motility of the colon.

Metoclopramide is well-absorbed orally, and distributed throughout the body. It penetrates the central nervous system (CNS) antagonizing dopamine at the receptor sites which explains its sedative, antiemetic, and prolactin secretion stimulation effects.

Metoclopramide crosses the placenta and is concentrated in milk at twice the level found in plasma. The majority of the drug is excreted primarily in the urine with only about 5% being excreted in feces.

Indications

Used as an upper GI motility stimulant for idiopathic and postsurgical causes of gastric stasis to improve gastric emptying. May also be helpful in some cases of esophageal regurgitation.

Drug Interactions or Contraindications

Do not use in animals with GI obstruction, perforation or hemorrhage.
Avoid use in animals with a history of seizures, as it may lower the seizure threshold.
Do not use in animals with pheochromocytoma as it may result in hypertension.
Metoclopramide may increase the rate and extent of GI absorption with tetracyclines.
Atropine may antagonize (oppose the effects) the GI motility effect of metoclopramide.
Metoclopramide may potentiate the effects anesthetics, antihistamines, barbiturates and tranquilizers. Avoid using together.

Adverse Reactions

CNS: The oral LD₅₀ in rats is 760mg/kg. Signs of overdose include extrapyramidal effects (EPS): sedation, ataxia, agitation, twitching (involuntary, irregular muscle movements), torticollis. Diphenhydramine (Benadryl) may be given as a supportive measure, to reduce hyperactive effects, related to overdose as deemed by veterinarian assessment.

GI: diarrhea, constipation (very dry feces)

GU: may increase urination

Dosage Recommendations

0.2 mg/kg to 1.0 mg/kg, PO, SC, IM, q12hr ¹^, ²⁶^, ²⁷^, ³⁴^, ³⁵^, ⁴¹^, ⁴⁴

Considerations

Contact veterinarian in the event the rat exhibits any abnormal changes in body posturing or behavior while on this medication.
Store tablets and syrup in tight, light resistance containers, at room temperature.

References

Plumb, D. C. (2008). Metoclopramide HCl. Plumb’s veterinary drug handbook (6th ed., pp. 606-608). Stockholm, Wis.: PharmaVet;.
REGLAN (metoclopramide hydrochloride) tablet [STAT RX USA LLC]. (2010, August 1). DailyMed. Retrieved September 17, 2013, from dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=55f1ee88-a455-44ba-b51a-2fcefe8eda65