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Stimulant Laxative Pregnancy: CONTRAINDICATED in pregnancy and lactation (§4.3 and §4.6). §4.6 verbatim: 'The use during pregnancy is contraindicated because of experimental data concerning a genotoxic risk of several anthranoids, e.g. emodin and aloe emodin.' 'The use during lactation is contraindicated because after administration of anthranoids, active metabolites, such as rhein, were excreted in [b]reast milk in small amounts.' Fertility: 'There are no data on the effects of the product on fertility.'

Senna

Brand names: Senokot, Manevac

Senna is a stimulant laxative for the short-term treatment of constipation.

Adult dose

Dose: Short-term relief of constipation: one to two tablets of Senokot 7.5 mg at night. 'The correct individual dose is the smallest required to produce a comfortable soft-formed motion.'
Route: Oral — 'For oral administration.'
Frequency: At night. 'New users should start with the lowest dose and increase it to the maximum dose if necessary. Once regularity has been regained dosage should be reduced and can usually be stopped.'
Max: Maximum two tablets (2 × Senokot 7.5 mg) at night. Duration ceiling: 'Not to be used for more than 1 week.'
VERBATIM UK SPC §4.2: 'For oral administration. The correct individual dose is the smallest required to produce a comfortable soft-formed motion. Adults, the elderly and children over 12 years: Swallow one to two tablets at night. Should not be used in children or adolescents under the age of 12 years (see section 4.3). New users should start with the lowest dose and increase it to the maximum dose if necessary. Once regularity has been regained dosage should be reduced and can usually be stopped. If no bowel action has occurred after three days of progressively increased dosage, a medical examination should be considered. Duration of use: Not to be used for more than 1 week. Usually it is sufficient to take this medicinal product up to two to three times during that week.' Some sections of the product information we used were incomplete — check the full SPC. ⚠ SCOPE — STRENGTH IS PRODUCT-SPECIFIC: the dose above is expressed in TABLETS of the fetched product, Senokot 7.5 mg Tablets 12 Years Plus. Do not restate it as a milligram figure for another presentation. NOT COVERED BY THIS BUNDLE: Manevac (this page's other listed brand) is a senna-with-ispaghula granule preparation dosed quite differently, and Senokot syrup and other senna presentations were not fetched — none of their regimens are in this source. §4.2 gives no dose for the elderly separate from adults. The label also states: 'This product should only be used if a therapeutic effect cannot be achieved by a change of diet or the administration of bulk forming agents' (§4.4).

Paediatric dose

Route: Oral
Frequency: At night; not to be used for more than 1 week
Max: Maximum two tablets (2 × Senokot 7.5 mg) at night, in children over 12 years only
dosePerKg is null deliberately: this product is NOT weight-based — children over 12 take the same fixed adult tablet dose, and there is no per-kg figure anywhere in the label. AGE LIMIT, VERBATIM §4.2: 'Adults, the elderly and children over 12 years: Swallow one to two tablets at night. Should not be used in children or adolescents under the age of 12 years (see section 4.3).' §4.3 lists 'Children under 12 years of age' as an outright CONTRAINDICATION for this product. This is a 12-years-plus presentation; any senna dosing for a younger child must come from a product licensed for that age and must be verified against a children's formulary.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Directions take preferably at bedtime or as directed by a doctor adults and children 12 years of age or older - starting dosage: 2 tablets once a day, maximum dosage: 4 tablets twice a day children 6 to under 12 years - starting dosage: 1 tablet once a day, maximum dosage: 2 tablets twice a day children 2 to under 6 years - starting dosage: 1/2 tablet once a day, maximum dosage: 1 tablet twice a day children under 2 years - starting dosage: ask a doctor, maximum dosage: ask a doctor

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2023-10-21. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients
  • Not to be used at the same time as other laxative agents
  • Intestinal obstruction and stenosis; atony
  • Appendicitis
  • Inflammatory bowel disease (e.g. Crohn's disease, ulcerative colitis)
  • Abdominal pain of unknown origin
  • Severe dehydration state with water and electrolyte depletion
  • Children under 12 years of age
  • Pregnancy and lactation
  • §4.4 adds: should not be taken by patients with faecal impaction, or with undiagnosed, acute or persistent gastro-intestinal complaints (e.g. abdominal pain, nausea and vomiting) unless advised by a doctor, as these can signal intestinal blockage (ileus)

Side effects

  • Frequency of all listed reactions is 'not known' (cannot be estimated from the available data)
  • Abdominal pain and abdominal spasm — in particular in patients with irritable colon; may also reflect individual overdosage, in which case dose reduction is necessary
  • Diarrhoea
  • Hypokalaemia — 'prolonged use of laxatives resulting in diarrhoea and subsequently hypokalaemia'
  • Gastrointestinal tract mucosal pigmentation — 'chronic use may cause pigmentation of the intestinal mucosa (pseudomelanosis coli), which usually recedes when the patient stops taking the preparation'
  • Chromaturia — 'yellow or red-brown (pH dependent) discolouration of urine by metabolites, which is not clinically significant'
  • Hypersensitivity, urticaria, asthma, hypogammaglobulinaemia
  • Pruritus, local or generalised exanthema
  • Finger clubbing, tetany and hypertrophic osteoarthropathy
  • Cachexia
  • 'Chronic use may lead to disorders in water equilibrium and electrolyte metabolism and may result in albuminuria and haematuria'

Monitoring

  • §4.2: 'If no bowel action has occurred after three days of progressively increased dosage, a medical examination should be considered.'
  • §4.4: 'If laxatives are needed every day, or abdominal pain persists, a doctor should be consulted. If laxatives are needed every day the cause of the constipation should be investigated.'
  • §4.4: 'Long-term use of stimulant laxatives should be avoided, as use for more than a brief period of treatment may lead to impaired function of the intestine and dependence on laxatives.' 'Prolonged use may precipitate the onset of an atonic, non-functioning colon.'
  • Electrolytes — §4.4: 'Prolonged excessive use may lead to fluid and electrolyte imbalance and hypokalaemia. Patients with kidney disorders should be aware of possible electrolyte imbalance.'
  • Hydration — §4.4: 'Intestinal loss of fluids may promote dehydration. Symptoms may include thirst and oliguria. In patients suffering from fluid loss where dehydration may be harmful (e.g. renal insufficiency, elderly patients) Senokot should be discontinued and only be restarted under medical supervision.'
  • §4.4: 'Patients taking cardiac glycosides, antiarrhythmic medicinal products, medicinal products inducing QT-prolongation, diuretics, adrenocorticosteroids or liquorice root, have to consult a doctor before taking senna leaf preparations concomitantly.'
  • Excipient — one tablet contains 15.82 mg lactose monohydrate; not for patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption
  • §4.4 (and patient leaflet): stimulant laxatives do not help with weight loss and do not reduce absorption of calories or nutrients; overuse can cause electrolyte and mineral disturbance

Clinical monograph

How it works

Its anthraquinone components stimulate colonic motility and secretion, usually producing a bowel movement within about 8-12 hours.

Prescribing in practice

  • Avoid in intestinal obstruction.
  • Use it short-term — prolonged use can lead to dependence and electrolyte disturbance.
  • Address underlying causes, fluid and fibre intake.

Monitoring

Review bowel habit; no routine monitoring.

Counselling the patient

  • It usually works overnight.
  • Drink plenty of fluids.
  • It is not for regular long-term daily use without advice.

Evidence & guidelines

A first-line stimulant laxative for constipation per NICE CKS guidance.

Reference: NICE NG31 Palliative Care — Constipation; SPC Senokot; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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