Hyoscyamine
LEVSIN
Pronunciation: hye-oe-SYE-a-meen
“Hi yo, C ya! (Leave soon!)”
mad as a hatter” → BBB-crossing antimuscarinic
What it isAntimuscarinic antispasmodic; IBS cramping, biliary and renal colic.
Why this oneSublingual dosing acts within minutes for acute cramping.
What limits itAnticholinergic burden is hazardous in older adults and in urinary retention or untreated narrow-angle glaucoma.
FDA-approved for
- GI spasm (~1950)
Principal riskAnticholinergic burden
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Anticholinergic/antispasmodic: peptic ulcer adjunct; GI/bladder spasm & hypermotility; IBS & functional GI disorders; neurogenic bladder/bowel; biliary/renal colic (with narcotics); rhinitis drying; Parkinsonism; anticholinesterase poisoning (manufacturer-labeled; unapproved drug) | Adults & peds ≥12 yr | 1–2 tab q4h or PRN | Adjust to conditions & symptom severity | 12 tablets/24 h |
| Same uses (manufacturer-labeled; unapproved drug) | Peds 2–<12 yr | ½–1 tab q4h or PRN | Adjust to conditions & symptom severity | 6 tablets/24 h |
Renal No labeled dose adjustment; use with caution in renal disease (substantially renally excreted; consider monitoring renal function in elderly)
Hepatic Undefined
Manufacturer labeling of an unapproved drug — not FDA-approved dosing
Instructions
- Oral tablet (label: absorbed by oral or sublingual administration)
- Administer before meals; give antacids after meals
Available strengths
- tab 0.125 mg
- ER tab 0.375 mg
- ODT 0.125 mg
- SL tab 0.125 mg
- chew tab 0.125 mg
- drops 0.125 mg/mL
- sol 0.125 mg/5 mL
- inj 0.5 mg/mL
Contraindications
- Glaucoma
- Obstructive uropathy (e.g. bladder neck obstruction from prostatic hypertrophy)
- Obstructive GI disease (achalasia, pyloroduodenal stenosis)
- Paralytic ileus; intestinal atony of elderly or debilitated
- Unstable cardiovascular status in acute hemorrhage
- Severe ulcerative colitis; toxic megacolon
- Myasthenia gravis
Cautions
- Heat prostration (decreased sweating) in high temperatures
- Diarrhea may signal incomplete intestinal obstruction (esp. ileostomy/colostomy)
- Drowsiness, dizziness, blurred vision — avoid driving/hazardous work
- Psychosis/CNS effects in sensitive individuals
- Caution: autonomic neuropathy, hyperthyroidism, CHD, CHF, arrhythmias, hypertension, renal disease, hiatal hernia with reflux esophagitis
- Investigate tachycardia before use
Adverse reactions
- Dry mouth
- Urinary hesitancy/retention
- Blurred vision, mydriasis
- Tachycardia, palpitations
- Headache
- Drowsiness, dizziness
- Nervousness, insomnia
- Nausea, vomiting
- Constipation, bloated feeling
- Confusion/excitement (esp. elderly)
- Decreased sweating
- Allergic reactions/urticaria
Pregnancy No animal reproduction studies; fetal harm unknown; crosses placenta; give only if clearly needed
Lactation Excreted in human milk; use caution in nursing women
Cost
| Strength | #/mo | generic $/mo | CostPlus | |
|---|---|---|---|---|
| 0.125 mg | tab | 90 TID | $13.13 | offered |
Generic entryBy 2023
Open Hyoscyamine in the interactive console ↗
Memory aids: interaction avatars
Open Hyoscyamine in the interactive console ↗
Self-check
- Which hyoscyamine route acts within minutes for cramping?
Sublingual. - Which untreated glaucoma type makes hyoscyamine hazardous?
Narrow-angle glaucoma.