Hyoscine

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Hyoscine is a tropane alkaloid that is also known as scopolamine. It is found with hyoscyamine in another alkaloidal extract, duboisine. It may be extracted from indigenous Philippine plants of the nightshade family such as lubi-lubi, tarambulo and malatalong.

Contents

Chemical nature

Hyoscine is a competitively reverses the effects of muscarine in the body which may include sweating, blurred vision, wheezing, vomiting, diarrhea, and urinary and fecal incontinence. In fact, it is classified pharmacologically as an anti-cholinergic, anti-muscarinic medication. It works by interfering with the transmission of nerve impulses of acetylcholine to the parasympathetic nervous system. This relaxes the involuntary muscles commonly found in the gut and the urinary tract.

Hyoscine was isolated in 1880 by Albert Ladenberg from solanaceous plants. From its structure, (–)-(S)-3-hydroxy-2-phenylpropionic acid(1R,2R,4S,7S,9S)-9-methyl-3-oxa-9-azatricyclo[3.3.1.02,4]non-7-yl ester, drugs such as diphenhydramine and pethidine are derived. It is available in various salts which include hydrochloride, hydrobromide, hydroiodide, and sulfate. Regardless of the salt or the formulation, this drug will take effect within 15 to 30 minutes.

Uses and common dosages

Hyoscine, aside from being one of the ancient drugs that are still being used in modern times, have a variety of uses. It is preferred over atropine since it is long acting. It is also used as anesthetic pre-medication and for urinary incontinence. It can address motion sickness, relieve spasms and cramps of the gastrointestinal tract, dilate pupils, and paralyze the ciliary muscle of the eyes. Some doctors may also prescribe this drug to prevent the production of excessive lung secretions for terminally ill patients.

Oral

  • Genito-urinary or gastro-intestinal tract spasm - A dose of 20 milligrams of butylbromide salt may be given every 6 hours.
  • Motion sickness - A 300 microgram hydrobromide salt may be given 30 minutes before travel. If needed, another dose of 300 micrograms may be given every 6 hours. This must not exceed 3 doses within a day.

Parenteral (through the veins)

  • Genito-urinary or gastro-intestinal tract spasm - A butylbromide salt will be given at 20 milligrams and repeated after 30 minutes, if needed. This must not exceed 100 milligrams within 24 hours.
  • Anesthetic pre-medication - A hydrobromide salt of 0.2 to 0.6 milligrams may be given 30 to 60 minutes before anesthesia is given through subcutaneous or intramuscular injection.
  • Prevention of nausea and vomiting - The hydrobromide salt may be given at 0.3 to 0.6 milligrams subcutaneously.
  • Pre-operative sedation. The hydrobromide salt will be given subcutaneously at 0.6 milligrams 3 to 4 times a day.

Ophthalmic

  • Mydriasis and cycloplegia for refraction - About 1 to 2 drops of 0.25% solution of the hydrobromide salt may be instilled on the eye 1 hour before the procedure.
  • Iridocyclitis - A 0.25% hydrobromide salt solution may be instilled 1 to 2 drops up to 4 times daily.

Transdermal

  • Prevention of motion sickness - A patch may deliver 1 milligram if hyoscine over 3 days. This patch must be applied behind the ears at least 4 hours before the journey.

Side effects

Common side effects might appear during treatment with hyoscine. These develop as the body adjusts to the medication.

  • Drowsiness, dizziness, and blurred vision
  • Dry mouth
  • Increased heart rate
  • Hallucinations
  • Photophobia
  • Small blisters on the hands or feet

Some conditions that might develop will have the doctor stop the medication. These include:

Precautions and contraindications

Hyoscine should be used with caution with the following condition listed below. Dose adjustment or shifting to another form of medication may be done by the healthcare provider.

Hyoscine must NOT be used in patients with:

  • Increased pressure in the eye
  • Allergies to belladonna alkaloids
  • Lack of bowel movements
  • Blockade of the gut
  • Abnormal enlargement of the colon
  • Muscle weakness disease
  • Enlarged prostrate
  • Narrow opening from the stomach to the intestines

Special patients such as the elderly, children, and pregnant and lactating women are also prohibited to use hyoscine.

Because of its dehydrating effects, hyoscine might interfere with gastric secretion tests. Patients taking this medication must also avoid engaging in activities that require increased alertness such as operating heavy machinery or driving. Dentists and surgeons must be informed if currently taking this medication.

It may also interact adversely with some drugs. The physician must be informed of the medications that might be taken with hyoscine.

  • Cocaine - Avoid this combination as it may lead to heart failure.
  • Marijuana - It may produce drowsiness and dry mouth.
  • Vitamin C - Decreased effect of hyoscine in very large doses.
  • Ketoconazole - Hyoscine dereases the effect of this drug.
  • Sertraline, guanfancine, and fluoxetine - Increased depressive effects.
  • Sedatives - Increased sedation from both drugs.
  • Phenothiazine, orphenadrine, meperidine, MAO inhibitors, and quinidine - Increased effect of hyoscine.
  • Potassium supplements - Possible intestinal ulcers.
  • Pilocarpine - Loss of effect of pilocarpine for glaucoma.
  • Nizatidine and ethinamate - Hyoscine increases the effect of this drug.
  • Nitrates and haloperidol - Increased internal eye pressure.
  • Nabilone - Potentiated depression of the central nervous system.
  • Encainide - Dangerous effects on the heart muscle.

Availability

Hyoscine is available as ampules, vials, and tablets in Philippine pharmacies. The ampule or vial is available in 10 or 20 milligrams per milliliter. Each tablet may contain 10 milligram of hyoscine. Transdermal preparations and eye drops may not be readily available. Popular brands include Buscopan ® and Busopin ®.

References