| name | movicol-prescribing-guide |
| description | Complete bedside prescribing reference for Movicol (macrogol 3350 + electrolytes) covering dosing for chronic constipation and faecal impaction, special population adjustments, contraindications, warnings, and drug interactions. Trigger when a clinician asks how to dose Movicol, how many sachets to prescribe, how to use Movicol for faecal impaction, whether Movicol is safe in pregnancy or renal failure, or what the contraindications to Movicol are. |
Movicol® (Macrogol 3350) — Prescribing Guide
Formulation: Each sachet (13.8 g powder) dissolved in 125 ml water
Class: Osmotic laxative (macrogol 3350 + balanced electrolytes)
Electrolytes per sachet: Na 65 mmol/L · K 5.4 mmol/L · Cl 53 mmol/L · HCO₃ 17 mmol/L
STEP 1 — Identify the Indication
| Indication | Definition |
|---|
| Chronic constipation | Infrequent or difficult bowel movements; ongoing need |
| Faecal impaction | Refractory constipation with faecal loading of rectum/colon — confirm by physical or radiological examination |
STEP 2 — Check Contraindications First
Do NOT use Movicol if:
- Intestinal perforation or obstruction (structural or functional)
- Ileus
- Severe inflammatory bowel disease: active Crohn's disease, ulcerative colitis, toxic megacolon
- Hypersensitivity to macrogol 3350 or any excipient
STEP 3 — Dose by Indication and Patient
🟦 Chronic Constipation
| Population | Dose | Duration |
|---|
| Adults, adolescents, elderly | 1–3 sachets daily in divided doses | Max 2 weeks per course; can repeat |
| Extended use (MS, Parkinson's, opioid/antimuscarinic-induced) | Adjust down to 1–2 sachets daily | Extended use permitted in these groups |
| Children <12 years | ❌ Not recommended — use Movicol Paediatric products | — |
Clinical studies show many patients respond to 1–2 sachets/day; dose typically reduces over time as stool consistency normalises.
🟥 Faecal Impaction
| Population | Dose | Duration |
|---|
| Adults, adolescents, elderly | 8 sachets daily, all consumed within a 6-hour period | Max 3 days |
| Impaired cardiovascular function | Max 2 sachets per hour (divide the 8 sachets over the day) | Max 3 days |
| Renal insufficiency | No dose adjustment needed | — |
| Children <12 years | ❌ Not recommended — use Movicol Paediatric products | — |
Preparation tip: For faecal impaction, all 8 sachets may be dissolved together in 1 litre of water.
STEP 4 — Administration Instructions
- Standard: Dissolve each sachet in 125 ml water
- Faecal impaction: Dissolve 8 sachets in 1 litre water
- Reconstituted solution must be used within 6 hours (store at 2–8°C if not used immediately)
- Sachets: store below 25°C
STEP 5 — Special Populations
| Population | Guidance |
|---|
| Renal insufficiency | No dose adjustment needed for either indication |
| Cardiovascular disease | For faecal impaction: max 2 sachets/hour (fluid load concern) |
| Pregnancy | Limited human data; animal studies show reproductive toxicity — use with caution, weigh risk/benefit |
| Breastfeeding | Safe — systemic absorption of macrogol 3350 is negligible |
| Driving / machinery | No effect |
STEP 6 — Warnings to Monitor
| Warning | Action |
|---|
| Fluid/electrolyte shifts (oedema, dyspnoea, fatigue, cardiac failure) | Stop immediately + check electrolytes |
| Diarrhoea | Reduce dose — usually resolves |
| Hyperkalaemia or hypokalaemia | Electrolyte monitoring if prolonged use or high-dose |
Drug Interactions
- Macrogol raises solubility of alcohol-soluble, water-insoluble drugs → altered absorption possible
- Transit rate increase may transiently reduce absorption of co-administered drugs
- Anti-epileptics: isolated reports of reduced efficacy — monitor levels
- General rule: space other oral medications away from Movicol doses where possible
Overdose
- Severe pain or distension → nasogastric aspiration
- Extensive fluid/electrolyte loss → correct electrolyte disturbances
Key Adverse Effects
| System | Effect |
|---|
| GI (most common) | Abdominal pain, diarrhoea, nausea, vomiting, bloating, flatulence, anal discomfort |
| Electrolytes | Hyperkalaemia, hypokalaemia |
| Immune | Allergic reactions (rare): anaphylaxis, angioedema, rash, urticaria |
| General | Peripheral oedema, headache |
Mild diarrhoea usually responds to dose reduction.
Clinical Guardrails
- Always confirm faecal impaction by physical or radiological exam before using the high-dose regimen
- Cardiovascular patients on impaction dose: must limit to 2 sachets/hour — rapid fluid load risk
- Do not use in IBD flares or obstruction — can cause perforation
- Extended use is acceptable for opioid/antimuscarinic-induced constipation and neurological disease (MS, Parkinson's) — adjust dose to minimum effective
- Pregnancy: caution warranted despite minimal absorption — animal reproductive toxicity data exist
Source: Movicol® 13.8 g Sachet — Summary of Product Characteristics (SPC). Norgine Limited, UK. Last revised 05/05/2011. PL 00322/0070.
