Hyoscyamine
LEVSIN
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)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Antispasmodic (adjust to symptom severity) | Adults & adolescents ≥12 yr | 1–2 tab SL TID–QID (30–60 min before meals & at bedtime) | May increase to q4h PRN | 12 tablets/24 h |
Renal Undefined
Hepatic Undefined
Do not exceed 12 tablets in 24 hours
Instructions
- Sublingual; may be taken with or without water
- Take 30–60 minutes before meals and at bedtime
- Not recommended in children under 12 years
Contraindications
- Glaucoma
- Obstructive uropathy
- Obstructive GI disease / paralytic ileus
- Intestinal atony (elderly or debilitated)
- Unstable cardiovascular status
- Severe ulcerative colitis / toxic megacolon
- Myasthenia gravis
- Myocardial ischemia
Cautions
- Geriatric patients may be more sensitive to usual adult dose
- Anticholinergic effects
Adverse reactions
- Dry mouth
- Urinary hesitancy/retention
- Blurred vision
- Tachycardia/palpitations
- Drowsiness, dizziness
- Constipation
- Confusion/excitement (esp. elderly)
- Decreased sweating
Pregnancy Category C; crosses placenta; use only if clearly needed
Lactation Undefined
NO BOXED WARNINGS
Principal riskAnticholinergic burden
Cost, est. cash$10–$300/month
Generic entryBy 2023
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.
Mechanism of action: Hyoscyamine ballicule
Open Hyoscyamine in the interactive console ↗
Memory aids: mascots and interaction avatars
mad as a hatter” → BBB-crossing antimuscarinic
