dicyclomine (Bentyl)

Introduction

Tradename: Bentyl.

Indications

irritable bowel syndrome

Dosage

• adults: 10-40 mg PO/IM QID
• children: 10 mg PO TID-QID

Tabs: 10 & 20 mg.

Syrup: 10 mg/5 mL, 10 mg/mL

Pharmacokinetics

• rapidly absorbed from GI tract
• peak levels in 1-1.5 hours after oral administration
• absorbed slightly faster after IM administration
• elimination
  • 1/2life is 9-10 hours
  • 80% of drug eliminated in the urine
  • 20% of drug eliminated in the feces

elimination via liver

elimination via kidney

Adverse effects

• common (> 10%)
• constipation
• decreased sweating
• dry mouth, nose, throat or skin
• reactions at injection site
• less common (1-10%)
  • diminished flow of breast milk, difficulty swallowing, blurred vision, photosensitivity
• uncommon (< 1%)
  • skin rash, confusion, increased intraocular pain, orthostatic hypotension, bloating, difficulty urinating, drowsiness, headache, lightheadedness, loss of memory, nausea/vomiting, weakness, tiredness, tachycardia, palpitations, seizures, asphyxia, coma, nervousness, excitement, confusion, insomnia, muscular hypotonia, urinary retention, respiratory distress
• other:
  • sedation

• drug adverse effects of parasympatholytics

Mechanism of action

• antispasmodic tertiary amine
• may act act non-selective smooth muscle relaxant
• little to no anti-muscarinic activity
• decreases abdominal pain by decreasing intestinal contractions

More general terms

• smooth muscle relaxant
• antiulcer agent
• parasympatholytic (anticholinergic, antimuscarinic agent)

Database

• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=3042
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=441344
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=6218
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=657341