Citrate of Magnesia, Citroma, Citro-Nesia
Classifications: saline cathartic;
Therapeutic: laxative

Prototype: Magnesium hydroxide
Pregnancy Category: B


1.75 g/30 mL solution


Hyperosmotic laxative. Promotes bowel evacuation by causing osmotic retention of fluid, which distends colon and stimulates peristaltic activity.

Therapeutic Effect

Evacuates bowels.


To evacuate bowel prior to certain surgical and diagnostic procedures and to help eliminate parasites and toxic materials after treatment with a vermifuge.


Severe renal impairment, renal failure; nausea, vomiting, diarrhea, abdominal pain, acute surgical abdomen; intestinal impaction, obstruction or perforation; rectal bleeding; use of solutions containing sodium bicarbonate in patients on sodium-restricted diets; children <2 y.

Cautious Use

Mild or moderate renal impairment; cardiac disease; older adults; pregnancy (category B).

Route & Dosage

Bowel Evacuation
Adult: PO 240 mL once
Child: PO 2–6 y, 4–12 mL; 6–12 y, 50–100 mL


  • Give on an empty stomach with a full (240 mL) glass of water. Time dosing so that it does not interfere with sleep. Drug produces a watery or semifluid evacuation in 2–6 h.
  • Chill solution by pouring it over ice or refrigerate it until ready to use to increase palatability.
  • Be aware that once container is opened, effervescence will decrease. This does not effect the quality of preparation.
  • Store at 2°–30° C (36°–86° F) in tightly covered containers.

Adverse Effects (≥1%)

GI: Abdominal cramps, nausea, fluid and electrolyte imbalance, hypermagnesemia (prolonged use).


Drug: May decrease effectiveness of digoxin, oral anticoagulants, phenothiazines; will decrease absorption of ciprofloxacin, tetracyclines; sodium polystyrene sulfonate will bind magnesium, decreasing its effectiveness.


Onset: 0.5–2 h.

Nursing Implications

Assessment & Drug Effects

  • Monitor for dehydration, hypokalemia, and hyponatremia (see Appendix F) since drug may cause intense bowel evacuation.

Patient & Family Education

  • Do not use for routine treatment of constipation (especially in older adult).
  • Expect some degree of abdominal cramping.

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

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