Anti-Spasmodic Agents

- Smooth muscle relaxants are important in patients who do not tolerate bowel insufflation.

Hyoscine Butylbromide

Pharmacology:
- Acts at parasympathetic ganglia in walls of viscera
- Half life: 2-3 minutes
- Large portion eliminated unchanged

Contra indications:
- Glaucoma
- Prostatic hypertrophy
- GI stenotic lesions
- Tachycardia, angina, cardiac failure
- Megacolon

Dose:
- 10-20 mg IV, IM or SC

Glucagon

Pharmacology:
- Single chain polypeptide (29 amino acids)
- Crystalline, white powder, insoluble in water
- Dissolves at pH between 3-9.5
- Stable in lyophilized form at room temperature
- Half life: 3-6 minutes

Mode of Action:
- Acts only on liver glycogen converting it into glucose.
- Relaxes smooth muscle of stomach, duodenum, small & large bowel

Contraindications:
- Hypersensitivity
- Pheochromocytoma

Dosage:
- 2.0 mg IM (10 minutes prior to study) or 1.0 mg IV
- IM has longer duration of effect than IV

Vial Constituents:
- 1 mg of Glucagon with 49.0 mg of lactose
- 1 ml of diluent solution (containing 1.2% of glycerine)

GI Motility Enhancers

Metoclopramide (Reglan, Maxeran)

Pharmacology:
- Stimulates tone, amplitude of gastric contractions
- Relaxes pyloric sphincter, duodenal cap
- Increases peristalsis of small bowel
- Half life: 2-3 hours

Contraindications:
- Gastric outlet obstruction, perforation
- GI hemorrhage
- Pheochromocytoma

Dose:
- 10 mg IV

References:

Bova JG, Bhattacharjee N, Jurdi R, Bennett WF. Comparison of no medication, placebo, and hyoscyamine for reducing pain during a barium enema. AJR 1999; 172:1285-1287.

Yee J, Hung RK, Akerkar GA, Wall SD. The usefulness of glucagon hydrochloride for colonic distention in CT colonography. AJR Am J Roentgenol. 1999;173(1):169-72.

Eli Lilly. Glucagon product brochure with vial.