Childrens Medications
Severe
Database
Severe dehydration in young children
Do not use <6 y
Source: Kimi deep-research + Cla
Drug reference
tenapanor
Sodium/hydrogen exchanger isoform 3 (NHE3) inhibitor · Prosecretory agent; Laxative
START
IBS-C: 50 mg PO BID before breakfast/dinner; CKD-HD: 30 mg BID
TYPICAL MAX
100 mg/day (IBS-C)
STOP IF
Severe diarrhoea / dehydration
WATCH
Hydration / electrolytes; phosphate (CKD); contraindicated <6 y
CDSCO approvedATC A06AX08
KDIGO 2024 + manufacturer label
- ONSET
- 1d · stool effect
- PEAK
- 1w · 1-wk benefit
- t½
- 36s · not absorbed
- DURATION
- 12h · BID
EXCRETION
Faecal — essentially unchanged
route + CYP
INTERACTIONS
1 major
SEVERE in our sources
PREGNANCY
Limited data; minimal systemic absorption — likely low risk.
FDA category + note
Top interactionssee all 5 →
- Childrens MedicationsSevereDatabaseKimi deep-research + Cla
Mechanism
Minimally absorbed small molecule that inhibits intestinal NHE3, reducing absorption of sodium (and indirectly phosphate); increases stool fluid (constipation relief in IBS-C) and lowers serum phosphate (CKD/dialysis).
Indications
Constipation-predominant irritable bowel syndrome (IBS-C)Hyperphosphataemia in adults with chronic kidney disease on dialysis
Dosing
- Adult
- IBS-C: 50 mg PO twice daily immediately before breakfast and dinner. Hyperphosphataemia (CKD-HD): 30 mg PO twice daily before meals, titrate to phosphate response.
- Pediatric
- Contraindicated <6 y; ≥6 y not established.
- Renal adjustment
- No adjustment (minimally absorbed).
- Hepatic adjustment
- No adjustment.
- Geriatric
- Standard adult dose.
- Max dose
- 100 mg/day (IBS-C); ~60 mg/day (hyperphosphataemia)
Pharmacokinetics
Onset
Constipation relief within 1 week; phosphate lowering over weeks
Peak effect
Local intestinal effect (sustained while dosing)
Duration
~12 h (twice-daily)
Half-life
Not measurable (minimal systemic exposure)
Bioavailability
<0.5% systemic
Protein binding
Not applicable
Metabolism
Not metabolised systemically
Excretion
Mainly faecal (essentially unchanged)
Contraindications
- Children <6 years (severe dehydration risk; boxed warning)
- Known/suspected bowel obstruction
- Hypersensitivity
Side effects
Common
DiarrhoeaAbdominal pain / distensionFlatulenceHeadache
Serious
- Severe dehydration (especially paediatric — boxed)
- Severe diarrhoea / electrolyte loss
- Severe hypersensitivity
Pregnancy & lactation
Pregnancy
Limited data; minimal systemic absorption — likely low risk.
Lactation
Limited data; minimal systemic absorption.
Drug interactions
Diuretics
Moderate
Database
Additive dehydration/electrolyte loss
Monitor hydration/electrolytes
Source: Kimi deep-research + Cla
Oatp2b1 Substrates
Moderate
Database
Tenapanor inhibits intestinal OATP2B1
Separate dosing by ≥4 h
Source: Kimi deep-research + Cla
Other Laxatives
Moderate
Database
Additive bowel-motility / fluid effect
Avoid stacking
Source: Kimi deep-research + Cla
Phosphate Binders
Moderate
Database
Additive phosphate lowering (intended)
Combination used in resistant cases
Source: Kimi deep-research + Cla
Related guidelines
Irritable bowel syndrome
ISG · Gastroenterology · 2023
Chronic kidney disease — assessment and management
KDIGO · Nephrology · 2024
Acute coronary syndrome in chronic kidney disease
CSI · Cardiology · 2020
Inflammatory bowel disease
OTHER · Gastroenterology · 2015
Empirical antimicrobial use in common syndromes
ICMR · Infectious Diseases · 2019
Ask House about tenapanor
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: Goodman & Gilman 14e·Verified: 2026-05-20 · House clinical team·Cockpit curated: 2026-05-20