Cholinesterase Inhibitors
Moderate
Database
Pharmacologic antagonism
Reassess combination
Source: Kimi deep-research + Cla
Drug reference
Trospium chloride
Quaternary antimuscarinic (overactive bladder) · Agent for Overactive Bladder
Also known as Flotros, Regurin, Uraplex, Regurin XL
START
20 mg PO twice daily on empty stomach (or ER 60 mg once daily)
TYPICAL MAX
40 mg/day (IR); 60 mg/day (ER)
STOP IF
Urinary retention, angle-closure glaucoma, or heatstroke
WATCH
Anticholinergic AEs, IOP risk, heat exposure (anhidrosis)
CDSCO approvedSchedule HATC G04BD09
KDIGO 2024 + manufacturer label
- ONSET
- 2h · absorption
- PEAK
- 5h · Tmax
- t½
- 20h · t½
- DURATION
- 12h · IR
EXCRETION
Mainly faecal (~85%); minor renal
route + CYP
INTERACTIONS
—
none in our sources
PREGNANCY
Limited data; use only if clearly needed.
FDA category + note
Mechanism
Quaternary amine antimuscarinic that blocks M3 receptors on bladder detrusor muscle, reducing involuntary contractions and urgency; quaternary structure limits CNS penetration → less cognitive AE than tertiary anticholinergics.
Indications
Overactive bladder (urge incontinence, urgency, frequency)
Dosing
- Adult
- 20 mg PO twice daily on empty stomach (≥1 h before meals or bedtime). ER 60 mg PO once daily.
- Pediatric
- Not established.
- Renal adjustment
- CrCl <30: 20 mg PO once daily at bedtime (IR); avoid ER form.
- Hepatic adjustment
- Severe hepatic impairment: not studied — caution.
- Geriatric
- ≥75 y: titrate based on tolerance; cognitive effects less than tertiary anticholinergics.
- Max dose
- 40 mg/day (IR); 60 mg/day (ER)
Pharmacokinetics
Onset
OAB symptom relief over 1–4 weeks
Peak effect
~5 h (Tmax)
Duration
~12 h (IR)
Half-life
~20 h
Bioavailability
<10% (quaternary; food markedly reduces)
Protein binding
~50–85%
Metabolism
Minimal hepatic; ester hydrolysis
Excretion
Mainly faecal (~85%); minor renal (~6%)
Contraindications
- Urinary retention
- Gastric retention / paralytic ileus
- Uncontrolled angle-closure glaucoma
- Myasthenia gravis
- Severe ulcerative colitis / toxic megacolon
Side effects
Common
Dry mouthConstipationHeadacheBlurred visionDyspepsia
Serious
- Urinary retention
- Acute angle-closure glaucoma
- Heatstroke (anhidrosis)
- Anaphylaxis / angioedema (rare)
Pregnancy & lactation
Pregnancy
Limited data; use only if clearly needed.
Lactation
Limited data; caution.
Drug interactions
Drugs Renally Secreted
Moderate
Database
Competition for renal secretion (OCT)
Monitor levels
Source: Kimi deep-research + Cla
Other Anticholinergics
Moderate
Database
Additive antimuscarinic burden
Avoid stacking (esp. elderly)
Source: Kimi deep-research + Cla
Agents Eliminated By Active Tubular Excretion
Mild
Textbook
Potential for pharmacokinetic interaction.
Not explicitly stated, but monitoring for altered drug levels or effects might be considered.
Source: G&G 14e · p216
Alcohol
Mild
Database
Possible dizziness
Counsel
Source: Kimi deep-research + Cla
Topiramate
Mild
Database
Additive risk of heatstroke (anhidrosis)
Caution in heat exposure
Source: Kimi deep-research + Cla
Ask House about Trospium chloride
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: Goodman & Gilman 14e, BNF·Verified: 2026-05-20 · House clinical team·Cockpit curated: 2026-05-20