Dicyclomine Injection: FDA-Approved Dosing and Critical Safety Precautions
Dicyclomine injection is administered intramuscularly at 10-20 mg four times daily in adults, for a maximum of 1-2 days only when oral administration is not possible, and is absolutely contraindicated in infants less than 6 months of age. 1
Dosage Recommendations
Adult Intramuscular Dosing
- Standard dose: 10-20 mg four times daily via intramuscular route only 1
- Duration limitation: Use for only 1-2 days maximum when oral medication cannot be taken 1
- Bioavailability consideration: IM injection is approximately twice as bioavailable as oral formulations, requiring dose adjustment when transitioning between routes 1
Administration Technique
- Route: Intramuscular injection ONLY—do not administer intravenously, subcutaneously, or by any other route 1
- Critical safety step: Aspirate the syringe before injecting to avoid intravascular injection, as thrombosis or thrombophlebitis may occur if inadvertently injected intravascularly 1
- Inspection: Visually inspect for particulate matter and discoloration prior to administration 1
Absolute Contraindications
Dicyclomine injection is contraindicated in the following populations 1:
- Infants less than 6 months of age (absolute contraindication)
- Nursing mothers
- Unstable cardiovascular status in acute hemorrhage
- Myasthenia gravis
- Glaucoma
- Obstructive uropathy
- Obstructive disease of the gastrointestinal tract
- Severe ulcerative colitis
- Reflux esophagitis
Critical Warnings and Precautions
Cardiovascular Risks
- May worsen pre-existing cardiovascular conditions 1
- Intravascular injection can cause thrombosis, thrombophlebitis, and injection site reactions 1
Central and Peripheral Nervous System Effects
- Heat prostration: Can occur due to decreased sweating, potentially leading to fever and heat stroke—discontinue immediately and institute supportive measures 1
- Psychosis and delirium: Reported in anticholinergic-sensitive patients (particularly elderly and those with mental illness); symptoms typically resolve within 12-24 hours after discontinuation 1
Special Population Considerations
- Myasthenia gravis: Overdose may lead to muscular weakness and paralysis; use only to reduce adverse muscarinic effects of anticholinesterase agents 1
- Incomplete intestinal obstruction: Diarrhea may be an early symptom, especially in patients with ileostomy or colostomy—treatment would be inappropriate and possibly fatal 1
- Salmonella dysentery: Risk of toxic megacolon 1
- Ulcerative colitis: Use with caution; large doses may suppress intestinal motility or aggravate toxic megacolon 1
- Prostatic hypertrophy: May lead to urinary retention 1
- Hepatic and renal disease: Use with caution 1
- Geriatric patients: More susceptible to adverse events 1
Common Adverse Reactions
The most common adverse reactions (>5% of patients) include 1:
- Dizziness
- Dry mouth
- Blurred vision
- Nausea
- Somnolence
- Asthenia
- Nervousness
The most serious adverse reactions involve cardiovascular and central nervous system symptoms 1.
Drug Interactions
- Antiglaucoma agents: Anticholinergics antagonize these agents and may increase intraocular pressure 1
- Other anticholinergic agents: May affect gastrointestinal absorption of various drugs and increase anticholinergic actions or side effects 1
- Antacids: Interfere with absorption of anticholinergic agents 1
Pediatric Considerations
Safety and effectiveness have not been established in pediatric patients 1. Research confirms that dicyclomine is not recommended in children younger than six months, with no role demonstrated in conditions like infantile colic 2.