Black-Draught, Gentlax B, Sen-exon, Senokot, Senolax
Classifications: gastrointestinal agent; stimulant laxative
Prototype: Bisacodyl
Pregnancy Category: C


8.6 mg, 15 mg, 25 mg tablets; 8.6 mg/5 mL, 15 mg/5 mL syrup


Prepared from dried leaflet of Cassia acutifolia or Cassia angustifolia. Similar to cascara sagrada but with more potent action. Senna glycosides are converted in colon to active aglycone, which stimulates peristalsis. Concentrate is purified and standardized for uniform action and is claimed to produce less colic than crude form.

Therapeutic Effects

Peristalsis stimulated by conversion of drug to active chemical.


Acute constipation and preoperative and preradiographic bowel evacuation.


Hypersensitivity; appendicitis, fecal impaction, irritable colon, nausea, vomiting, undiagnosed abdominal pain, intestinal obstruction; pregnancy (category C), lactation.

Cautious Use

Diabetes mellitus; fluid and electrolyte imbalances.

Route & Dosage

Adult: PO Standard Senna Concentrate 1–2 tablets or –1 tsp h.s. (max: 4 tablets or 2 tsp b.i.d.); Syrup, Liquid 10–15 mL at h.s.
Child: PO Standard Senna Concentrate >27 kg, 1 tablet or tsp h.s.; Syrup, Liquid 1 mo–1 y, 1.25–2.5 mL h.s.; 1–5 y, 2.5–5 mL h.s.; 5–15 y, 5–10 mL h.s.



Adverse Effects (1%)

GI: Abdominal cramps, flatulence, nausea, watery diarrhea, excessive loss of water and electrolytes, weight loss, melanotic segmentation of colonic mucosa (reversible).


Onset: 6–10 h; may take up to 24 h. Metabolism: Metabolized in liver. Elimination: Excreted in feces.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug