What is the recommended treatment regimen for an adult patient with chronic idiopathic constipation using Trulance (plecanatide)?

Trulance (Plecanatide) Treatment Regimen for Chronic Idiopathic Constipation

The recommended treatment regimen for adults with chronic idiopathic constipation is plecanatide 3 mg taken orally once daily, with or without food, after failing over-the-counter laxatives. 1, 2

Dosing and Administration

• Standard dose: 3 mg orally once daily 2
• Timing: Can be taken with or without food 1, 2
• Missed dose: Skip the missed dose and take the next dose at the regular time; never double dose 2
• Tablet administration: Swallow whole, or if swallowing difficulties exist, crush and mix with applesauce or water 2

When to Initiate Plecanatide

Start plecanatide only after inadequate response to over-the-counter agents (polyethylene glycol, fiber, or other OTC laxatives). 1 The 2023 AGA-ACG guidelines provide a strong recommendation for plecanatide as a second-line agent with moderate certainty of evidence. 1

• Can be used as replacement or adjunct to OTC agents 1
• Trial duration before escalation: The clinical trials evaluated 12-week treatment periods, though the FDA label does not specify a maximum duration 1, 2

Mechanism and Expected Benefits

Plecanatide is a guanylate cyclase-C agonist that increases intestinal fluid secretion and accelerates GI transit. 1 Patients can expect:

• Increased complete spontaneous bowel movements (CSBMs): Mean increase of 1.1 CSBMs per week 1
• Increased spontaneous bowel movements (SBMs): Mean increase of 1.66 SBMs per week 1
• Improved stool consistency: Mean improvement of 0.83 points on Bristol Stool Form Scale 1
• Enhanced quality of life scores 1
• Response rate: 88 more responders per 1,000 patients treated compared to placebo 1

Critical Safety Considerations

Diarrhea is the most common adverse effect, occurring in 3.2-5% of patients at the 3 mg dose. 1, 2, 3

• Risk of treatment discontinuation due to diarrhea: 27 more per 1,000 patients compared to placebo, though absolute risk remains small 1
• Management of severe diarrhea: Suspend dosing and rehydrate the patient 2
• Most adverse events are mild to moderate in severity 3, 4

Absolute Contraindications

Never use plecanatide in:

• Patients under 6 years of age (risk of fatal dehydration) 2
• Known or suspected mechanical gastrointestinal obstruction 2

Avoid in patients 6 to less than 18 years of age (safety and effectiveness not established) 2

Special Populations

• Elderly patients (≥65 years): No clear differences in outcomes observed in clinical trials, though sample sizes were limited for formal age-based analysis 1
• Patients with swallowing difficulties: Crush tablet and administer with applesauce or water, or via nasogastric/gastric feeding tube per specific instructions 2

Long-Term Safety Profile

Long-term data from a 72-week open-label study demonstrated:

• Low discontinuation rate: Only 5.3% discontinued due to adverse events, with 3.1% specifically due to diarrhea 4
• High patient satisfaction: Median score of 4.0 (quite satisfied) with desire to continue treatment 4
• Consistent safety profile: Adverse events remained qualitatively and quantitatively similar to short-term trials 4

Clinical Algorithm for Treatment Escalation

1. First-line: Polyethylene glycol 17g daily ± senna 8.6-17.2 mg at bedtime 5, 6
2. If inadequate response after 4-12 weeks: Initiate plecanatide 3 mg daily 1, 6
3. Monitor for diarrhea: If severe, suspend dosing and rehydrate 2
4. Continue indefinitely if effective: No maximum duration specified in FDA label 1, 2

Common Pitfalls to Avoid

• Do not use in pediatric patients: Fatal dehydration risk in children under 6 years 2
• Do not continue escalating OTC laxatives indefinitely: Switch to prescription agents like plecanatide after 4-12 weeks of inadequate response 6
• Do not use with mechanical obstruction: Rule out obstruction before initiating therapy 2
• Do not double dose if missed: Simply resume regular schedule 2