Hyoscyamine
Antispasmodic & Anticholinergic · Anticholinergic
Indications
Spasm and painful conditions of the gastro intestinal, genito-urinary and biliary tracts.
Dosage
DROP: The following dosage may be repeated every 4 hr. Adults: 20-40 drops. Children: 1-10 yr, 10-20 drops. TABLET: Adults: 125-250 mcg may be given three to four times daily. Children: Not recommended.
Adverse Effects
Constipation, transient bradycardia (followed by tachycardia, palpitation and arrhythmias), reduced bronchial secretions, urinary urgency and retention, dilatation of the pupils with loss of accommodation, photophobia, dry mouth, flushing and dryness of the skin. Side-effects that occur occasionally include confusion (particularly in the elderly), nausea, vomiting and giddiness. Very rarely, angle-closure glaucoma may occur.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Contraindicated in pregnancy. Lactation: Caution advised or effect undetermined. Contraindications: Antimuscarinics are contra-indicated in Myasthaenia gravis (but may be used to decrease muscarinic side-effects of anticholinesterases), paralytic ileus, pyloric stenosis, toxic megacolon and prostatic enlargement. Precautions: Antimuscarinics should be used with caution in Down's syndrome, in children and in the elderly; they should also be used with caution in gastro-esophageal reflux disease, diarrhoea, ulcerative colitis, autonomic neuropathy, acute myocardial infarction, hypertension, conditions characterised by tachycardia (including hyperthyroidism, cardiac insufficiency, cardiac surgery), pyrexia and in individuals susceptible to angle-closure glaucoma.
Interactions
Amantadine, atenolol, digoxin, phenothiazines, tricyclic antidepressants.
Advice to Patient
Take 30 to 60 minutes before meals. Swallow whole, do not crush or chew extended release form. Take bedtime dose at least 2 hours after last meal of day. To take sublingual tablet, place it under tongue and allow to dissolve. To take orally-disintegrating tablet, place it on tongue and allow to disintegrate before swallowing, it may be taken with or without food. Contact prescriber if there is blurred vision, headache, flushing, tachycardia, nervousness, constipation, dizziness, insomnia, mental confusion or excitement, dry mouth, altered taste perception, dysphagia, palpitations, bradycardia, urinary hesitancy or retention, impotence, decreased sweating. Void immediately before taking medication. Avoid extreme heat and humidity. Wear dark glasses in bright sunlight to avoid photosensitivity.
Pharmacokinetics
Onset: Tab: 20-30 mins. Sub-lingual/chewable tab: 5-20 mins. Oral soln: 5-20 mins. Extended-release cap: 20-30 mins. Inj: 2-3 mins. Duration: Up to 4 hrs. Extended-release preparation: Up to 12 hrs. Absorption: Oral: Well absorbed. Metabolism: Hepatic. Bioavailability: Extended release cap: Relative bioavailability: 43%. Extended-release tab: Relative bioavailability: 92%. Half-life elimination: Immediate release prep: Normal renal function: 2-3.5 hrs. Renal dysfunction: Prolonged. Extended-release cap: 5-7 hrs. Extended-release tab: 7-9 hrs. Biphasic elimination: Terminal phase: =12.5 hrs. Time to peak, serum: Tab: 30-60 mins. Sub-lingual/chewable tab: 30-60 mins. Oral soln: 30-60 mins. Extended-release cap: 40-90 mins. Inj: 15-30 mins. Excretion: Urine (approx. 30%-50% as unchanged drug and remaining as metabolites).
Brands with this active ingredient
Compiled by Healify Pharmacy from published drug references. How we compile it →
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