Hyoscyamine

Today's med: Hyoscyamine (hye oh SYE a meen) 

(brand names: Anaspaz, ED-SPAZ, HyoMax (SR, SL, DT, FT), Hyosyne, Levbid, Levsin, NuLev, Oscimin, Symax (DuoTab, FasTab, SL, SR)

Drug Class: Anticholinergic Agent

Indications: 

Oral: Adjunctive therapy for peptic ulcers, irritable bowel, neurogenic bladder/bowel; treatment of infant colic, GI tract disorders caused by spasm; to reduce rigidity, tremors, sialorrhea, and hyperhidrosis associated with parkinsonism; as a drying agent in acute rhinitis

Injection: Preoperative antimuscarinic to reduce secretions and block cardiac vagal inhibitory

reflexes; to improve radiologic visibility of the kidneys; symptomatic relief of biliary and renal

colic; reduce GI motility to facilitate diagnostic procedures (ie, endoscopy, hypotonic

duodenography); reduce pain and hypersecretion in pancreatitis, certain cases of partial heart

block associated with vagal activity; reversal of neuromuscular blockade

Action: Blocks the action of acetylcholine at parasympathetic sites in smooth muscle,

secretory glands, and the CNS; increases cardiac output, dries secretions, antagonizes

histamine and serotonin

Contraindications: Hypersensitivity to belladonna alkaloids or any component of the formulation; glaucoma; obstructive uropathy; myasthenia gravis; obstructive GI tract disease, paralytic ileus, intestinal atony of elderly or debilitated patients, severe ulcerative colitis, toxic megacolon complicating ulcerative colitis; unstable cardiovascular status in acute hemorrhage, myocardial ischemia

Adverse Effects: Cardiovascular: Palpitation, tachycardia

Central nervous system: Ataxia, dizziness, drowsiness, headache, insomnia, mental confusion/excitement, nervousness, speech disorder

Dermatologic: Urticaria

Endocrine & metabolic: Lactation suppression

Gastrointestinal: Bloating, constipation, dry mouth, loss of taste, nausea, vomiting

Genitourinary: Impotence, urinary hesitancy, urinary retention

Neuromuscular & skeletal: Weakness

Ocular: Blurred vision, cycloplegia, increased ocular tension, mydriasis

Miscellaneous: Allergic reactions, sweating decreased

Warning: Concerns related to adverse effect:

• CNS effects: May cause drowsiness and/or blurred vision, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).

• Diarrhea: May be a sign of incomplete intestinal obstruction, treatment should be discontinued if this occurs.

• Heat prostration: May occur in the presence of increased environmental temperature; use caution in hot weather and/or exercise.

• Psychosis: Has been reported in patients with an extreme sensitivity to anticholinergic effects.

Disease-related concerns:

• Cardiovascular disease: Use with caution in patients with coronary artery disease, tachyarrhythmias, heart failure, or hypertension; evaluate tachycardia prior to administration.

• Hiatal hernia: Use with caution in patients with hiatal hernia with reflux esophagitis.

• Hyperthyroidism: Use with caution in patients with hyperthyroidism.

• Neuropathy: Use with caution in patients with autonomic neuropathy.

• Prostatic hyperplasia: Use with caution in patients with prostatic hyperplasia.

• Renal impairment: Use with caution in patients with renal impairment.

Special populations:

• Elderly: Avoid use in this age group due to potent anticholinergic adverse effects and uncertain effectiveness (Beers Criteria).

• Pediatrics: Use with caution in children with spastic paralysis.

Standard Dosing: 

Oral: Children: Gastrointestinal disorders: Dose as listed, based on age and weight (kg) using 0.125 mg/mL drops; repeat dose every 4 hours as needed:

Children <2 years:

3.4 kg: 4 drops; maximum: 24 drops/24 hours

5 kg: 5 drops; maximum: 30 drops/24 hours

7 kg: 6 drops; maximum: 36 drops/24 hours

10 kg: 8 drops; maximum: 48 drops/24 hours

Oral, S.L.:

Children 2-12 years: Gastrointestinal disorders: Dose as listed, based on age and weight (kg); repeat dose every 4 hours as needed:

10 kg: 0.031-0.033 mg; maximum: 0.75 mg/24 hours

20 kg: 0.0625 mg; maximum: 0.75 mg/24 hours

40 kg: 0.0938 mg; maximum: 0.75 mg/24 hours

50 kg: 0.125 mg; maximum: 0.75 mg/24 hours

Children >12 years and Adults: Gastrointestinal disorders: 0.125-0.25 mg every 4 hours or as needed (before meals or food); maximum: 1.5 mg/24 hours

Oral (timed release): Children >12 years and Adults: Gastrointestinal disorders: 0.375-0.75 mg every 12 hours; maximum: 1.5 mg/24 hours

I.M., I.V., SubQ: Children >12 years and Adults: Gastrointestinal disorders: 0.25-0.5 mg; may repeat as needed up to 4 times/day, at 4-hour intervals

I.V.: Children >2 year and Adults: I.V.: Preanesthesia: 5 mcg/kg given 30-60 minutes prior to induction of anesthesia or at the time preoperative narcotics or sedatives are administered

I.V.: Adults: Diagnostic procedures: 0.25-0.5 mg given 5-10 minutes prior to procedure

To reduce drug-induced bradycardia during surgery: 0.125 mg; repeat as needed

To reverse neuromuscular blockade: 0.2 mg for every 1 mg neostigmine (or the physostigmine/pyridostigmine equivalent)

Dosage adjustment in renal impairment: No dosage adjustment provided in manufacturer’s labeling, use with caution.

Dosage adjustment in hepatic impairment: No dosage adjustment provided in manufacturer’s labeling.

Administration: Take before meals. Do not crush or chew extended release form; swallow whole. You may experience dizziness, blurred vision, dry mouth, photosensitivity, decreased ability to sweat, or impotence (temporary). Report excessive and persistent anticholinergic effects (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).

Oral: Tablets should be administered before meals or food.

Levbid®: Tablets are scored and may be broken in half for dose titration; do not crush or chew.

Levsin/SL®: Tablets may be used sublingually, chewed, or swallowed whole.

Symax® SL: Tablets may be used sublingually or swallowed whole.

I.M.: May be administered without dilution.

I.V.: Inject over at least 1 minute. May be administered without dilution.

Dietary Considerations: Should be taken before meals or food

Drug interactions: http://www.drugs.com/drug-interactions/hyoscyamine.html

A total of 576 drugs (4181 brand and generic names) are known to interact with hyoscyamine.

• 20 major drug interactions (122 brand and generic names)
• 472 moderate drug interactions (3421 brand and generic names)
• 84 minor drug interactions (638 brand and generic names)

Show all medications in the database that may interact with hyoscyamine.

Hyoscyamine blocks acetylcholine.