Hyoscine butylbromide


Hyoscine butylbromide, also known as scopolamine butylbromide and sold under the brandname Buscopan among others, is a medication used to treat crampy abdominal pain, esophageal spasms, renal colic, and bladder spasms. It is also used to improve respiratory secretions at the end of life. Hyoscine butylbromide can be taken by mouth, injection into a muscle, or into a vein.
Side effects may include sleepiness, vision changes, dry mouth, rapid heart rate, triggering of glaucoma, and severe allergies. Sleepiness is uncommon. It is unclear if it is safe in pregnancy. It appears safe in breastfeeding. Greater care is recommended in those with heart problems. It is an anticholinergic agent, which does not have much effect on the brain.
Hyoscine butylbromide was patented in 1950, and approved for medical use in 1951. It is on the World Health Organization's List of Essential Medicines. It is not available in the United States, and a similar compound methscopolamine may be used instead. It is manufactured from hyoscine which occurs naturally in the plant deadly nightshade.

Medical uses

Hyoscine butylbromide is effective in treating crampy abdominal pain.
Hyoscine butylbromide is effective in reducing the duration of the first stage of labour, and it is not associated with any obvious adverse outcomes in mother or neonate.
It is also used during abdominal or pelvic MRI or CT scans to improve the quality of pictures.

Side effects

As little of the medication crosses the blood brain barrier it has less effect on the brain and therefore has reduced occurrence of the centrally mediated effects which hinder the usefulness of some other anticholinergic drugs. Hyoscine butylbromide is still capable of impacting the chemoreceptor trigger zone due to the lack of a well-developed blood-brain-barrier in the medulla oblongata, which potentiates the antiemetic effects that it produces via local action on the smooth muscle of the gastrointestinal tract.

Pharmacology

Hyoscine butylbromide reduces the stimulation of smooth muscle contraction and the production of respiratory secretions. These are normally stimulated by the parasympathetic nervous system, via the neurotransmitter acetylcholine. As an antimuscarinic, hyoscine butylbromide binds to muscarinic acetylcholine receptors, blocking their effect.
It is a quaternary ammonium compound and a semisynthetic derivative of hyoscine hydrobromide. The attachment of the butyl-bromide moiety effectively prevents the movement of this drug across the blood–brain barrier, effectively minimising undesirable central nervous system side effects associated with scopolamine/hyoscine.

Abuse

Hyoscine butylbromide is not centrally active and has a low incidence of abuse. In 2015, it was reported that prisoners at Wandsworth Prison and other UK prisons were smoking prescribed hyoscine butylbromide, releasing the potent hallucinogen scopolamine. There have also been reports of abuse in Mashhad Central Prison in Iran.