Hyoscine Butylbromide

Hyoscine Butylbromide is an antispasmodic used to treat abdominal pain and bladder spasms by relaxing smooth muscles. It works by blocking acetylcholine, reducing muscle contractions. Hyoscine Butylbromide was first approved in the 1950s in Europe and later in the 1960s in the U.S. by the FDA under the brand name Buscopan. It was recognized by the WHO as an essential medicine due to its effectiveness in treating smooth muscle spasms, particularly in the gastrointestinal and urogenital systems. Over time, it became available as a generic drug worldwide.

BRAND NAME

Buscopan: Buscopan 20mg Injection is an anticholinergic that relaxes stomach and intestinal muscles, relieving cramps, pain, bloating, and discomfort by stopping sudden muscle spasms.

MECHANISM OF ACTION

Hyoscine Butylbromide functions as an anticholinergic by blocking acetylcholine from binding to muscarinic receptors in smooth muscle cells. Normally, acetylcholine stimulates these receptors, causing muscle contractions in the stomach and intestines. By preventing this binding, Buscopan inhibits muscle spasms, leading to relaxation of the smooth muscles. This action helps alleviate abdominal cramps, bloating, and pain associated with gastrointestinal disorders, such as irritable bowel syndrome (IBS). Essentially, Buscopan relaxes muscles by stopping the neurotransmitter from triggering contractions

PHARMACOKINETICS

Absorption:

Hyoscine Butylbromide is rapidly absorbed after oral administration. It is also available in injectable and rectal forms. The drug undergoes minimal absorption when taken orally because it is poorly absorbed through the gastrointestinal tract due to its quaternary ammonium structure.

Distribution:

Once absorbed, it is distributed widely throughout the body, but its penetration into the central nervous system is minimal due to its quaternary structure, which prevents it from crossing the blood-brain barrier. It primarily acts on smooth muscle, where it binds to muscarinic receptors to exert its antispasmodic effects.

Metabolism:

The metabolism of Hyoscine Butylbromide occurs in the liver, where it undergoes hydrolysis and other processes to form inactive metabolites.

Excretion:

The drug is mainly excreted unchanged in the urine. A small portion of the drug is excreted through the feces. The elimination half-life of Hyoscine Butylbromide is typically around 1-2 hours, which is relatively short.

DOSAGE AND ADMINISTRATION

Oral Tablets:

Adults: 10-20 mg 3 to 5 times a day, depending on the severity of symptoms.
Maximum Dose: 100 mg per day.
Pediatric: Not recommended for children under 6 years old. For children aged 6-12, the usual dose is 0.3-0.6 mg/kg/day, divided into multiple doses.

Injectable (Intramuscular or Intravenous):

Adults: 20-40 mg, up to 3 times a day, as needed.
Pediatric: Not recommended for children under 6 years.

Suppositories:

Adults: Typically 10-20 mg 1-2 times daily.

DRUG INTERACTIONS

Anticholinergic Drugs: Increased anticholinergic effects (e.g., dry mouth, constipation).
Antihistamines: Enhanced sedation and dry mouth.
CNS Depressants: Increased sedation when combined with sedatives or alcohol.
MAO Inhibitors: Enhanced side effects.
Other Muscarinic Antagonists: Increased anticholinergic effects.
Gastrointestinal Motility Drugs: Reduced effectiveness of pro-kinetic agents.
Tricyclic Antidepressants: Intensified anticholinergic effects.

CONTRAINDIACTIONS

Glaucoma: Increases intraocular pressure, worsening glaucoma.
Myasthenia Gravis: May exacerbate muscle weakness.
Tachycardia: Can worsen conditions involving rapid heart rate.
Urinary Retention: Can aggravate symptoms in patients with urinary retention or obstructive uropathy.
Severe Liver or Kidney Impairment: May not be metabolized or excreted effectively.
Hypersensitivity: Known allergy or hypersensitivity to Hyoscine Butylbromide or any of its components.

SIDE EFFECTS

Common Side Effects: