What are the side effects of Reglan (metoclopramide)?

Side Effects of Reglan (Metoclopramide)

Metoclopramide (Reglan) can cause serious neurological side effects including potentially irreversible tardive dyskinesia, and should not be used long-term due to these risks.

Common Side Effects

• Neurological effects:

  • Restlessness, drowsiness, fatigue, and lassitude 1
  • Dizziness and anxiety 1
  • Headache 1
  • Confusion 1

• Gastrointestinal effects:

  • Diarrhea 2
  • Nausea 1
  • GI upset 2

• Other common effects:

  • Muscle weakness 2
  • Upper respiratory tract infections 1
  • Trouble sleeping 1

Serious Side Effects

Neurological Adverse Effects

• Extrapyramidal symptoms (EPSEs):

  • Uncontrolled spasms of face, neck, and body muscles (dystonia) - typically occur within the first 2 days of treatment and are more common in children and adults under 30 1
  • Parkinsonism symptoms - slight shaking, body stiffness, trouble moving or keeping balance 1

• Tardive dyskinesia:

  • Potentially irreversible involuntary movements 1, 3
  • Risk is estimated at approximately 0.1% per 1000 patient-years, which is lower than the previously estimated 1-10% 3
  • High-risk groups include elderly females, diabetics, patients with liver or kidney failure, and those on concomitant antipsychotic therapy 3

• Neuroleptic Malignant Syndrome (NMS):

  • Rare but very serious condition that can be fatal 1
  • Symptoms include high fever, stiff muscles, problems thinking, very fast or uneven heartbeat, and increased sweating 1

• Psychiatric effects:

  • Depression, thoughts about suicide 1

Other Serious Side Effects

• Cardiovascular effects:

  • Hypotension 2
  • Tachycardia 2
  • Arrhythmias 2

• Endocrine effects:

  • Elevated prolactin levels leading to galactorrhea, amenorrhea, gynecomastia, and impotence 1

• Fluid retention:

  • Particularly in patients with cirrhosis or congestive heart failure 1

Risk Factors for Adverse Effects

• Duration of use:

  • Side effects increase with longer duration of use 1
  • Not intended for long-term use; oral preparations recommended for 4-12 weeks maximum 4
  • Parenteral use should be limited to 1-2 days 4

• Dose-related risks:

  • Higher doses increase risk of side effects 1
  • Intravenous injections should be administered slowly (over 1-2 minutes for 10 mg) to avoid intense anxiety and restlessness 1

• Patient-specific risk factors:

  • Age: Elderly patients are at higher risk for side effects 2, 3
  • Gender: Females at higher risk for tardive dyskinesia 3
  • Medical conditions: Diabetes, liver or kidney failure increase risk 3
  • Concomitant medications: Antipsychotics increase risk of neurological complications 3

Special Precautions

• Contraindications:

  • Pheochromocytoma 2
  • Seizure disorder 2
  • GI bleeding or obstruction 1
  • History of tardive dyskinesia 2
  • Parkinson's disease (may worsen symptoms) 1

• Drug interactions:

  • Anticholinergic drugs and narcotic analgesics antagonize metoclopramide's effects on GI motility 1
  • Additive sedative effects with alcohol, sedatives, hypnotics, narcotics, or tranquilizers 1
  • Caution with MAO inhibitors 1
  • May affect absorption of other drugs (diminishes absorption from stomach, increases from small bowel) 1

Monitoring and Management

• Monitor for early signs of tardive dyskinesia and discontinue immediately if they appear 1
• For patients requiring long-term therapy, use the lowest effective dose 2
• Avoid in patients with history of depression or other psychiatric disorders when possible 1
• Discontinue if fluid retention occurs 1

Remember that even short-term, low-dose use can occasionally result in severe and long-lasting adverse effects, as documented in case reports 5. The European Medicines Agency's Committee recommends that metoclopramide not be used long-term due to its risk profile 2.