Docusate

Constipation is a common complaint encountered in the clinical practice with a prevalence of 16% in all adults and 33% in adults older than 60 years. There is no universally applicable definition of constipation. Most physicians consider constipation as infrequent bowel movements, typically less than three per week. However, patients report constipation with a broader set of symptoms that may include difficulty in passing stool, harder stool consistency, abdominal cramping, and incomplete stool evacuation.[1]

The non-pharmacological management of chronic constipation starts with patient education and modifying dietary and lifestyle habits. It is essential to clarify to patients that not having a daily bowel movement is not abnormal or necessary. Increased physical activity is associated with lower rates of constipation.[2] The dietary changes must encourage increased consumption of fluid and fiber-rich foods. If all these modulations do not overcome constipation, then the laxative use comes into play.

There are different classes of laxatives used in the treatment of constipation:

• Bulk-forming laxatives (methylcellulose, psyllium)
• Osmotic agents (polyethylene glycol, lactulose, magnesium citrate)
• Stimulant laxatives (Bisacodyl, Senna)
• Surfactants/stool softeners (docusate, liquid paraffin)
• Lubricants (mineral oil)
• Prokinetic agents (tegaserod, cisapride)
• Newer Agents [3][4]:
  • Linaclotide: guanylate cyclase-C agonist, stimulates peristalsis through increased fluid secretion and reduced visceral hypersensitivity.
  • Lubiprostone: chloride channel activator, stimulates intestinal secretion, and improves motility.

Docusate or dioctyl sulfosuccinate is available in two salt preparations for the oral route - docusate sodium and docusate calcium. Docusate carries a "Human Over The Counter" (OTC) drug label and has the marketing status of  "OTC monograph not final" under the U.S National Library of Medicine, DailyMed resource. The FDA has not approved the drug, and the medication is not in the FDA list of approved drugs.

There no FDA approved indications for docusate.

According to the product monograph, indications for docusate include avoiding difficult or painful defecation, when peristaltic stimulants are contraindicated.

Docusate eases the passage of hard stools. This property can be helpful in patients with painful anorectal conditions or cardiac comorbidities. Stool softening occurs within 12 to 72 hours following initiation of therapy.

Docusate sodium is also used off-label as a ceruminolytic.[5] 

Docusate is an emollient stool softener (surfactant laxatives). By lowering the surface tension of the oil-water interface of the stool, it allows the passage of water and lipids into the stool mass. As a result, the stool softens and passes easily through the intestinal tract.[6]

Numerous systematic reviews have investigated the efficacy of docusate and found no significant evidence to support its use.[7][8][9][10] Despite that, docusate remains one of the most prescribed of all laxatives.[11]

Docusate is administered either orally (in the form of a tablet, capsule, liquid, syrup) or rectally (suppositories, enema).[12]

Oral docusate sodium is administered once daily or in divided doses, while docusate calcium dosing is once a day.

Rectal enema dosing can be one to three times daily.

As a ceruminolytic, the liquid docusate is administered intra-aurally via a syringe and can require irrigation with luke-warm saline.[5]

The adverse effects of docusate are generally mild. Anorexia, diarrhea, and vomiting are usually associated with excess doses of medication. Abdominal cramping is a reported adverse effect. A rash can present but is rare.[6] Syrup and liquid formulation can cause throat irritation and bitter taste. Therefore administration with adequate amounts of water is recommended. Mixing with milk or fruit juice may alleviate throat irritation. 

Docusate use is not associated with adverse outcomes in pregnancy, and therefore it is considered safe to use.[13][14]

However, in one case report, chronic docusate sodium intake in pregnancy showed a correlation with symptomatic hypomagnesemia in the neonate.[15]

Contraindications and precautions related to docusate are:

• Hypersensitivity reaction to any of the docusate ingredients.
• Avoid concomitant use of mineral oil. Increased absorption of the oil may result. 
• Nausea or vomiting. Due to the need to drink a lot of fluid with the use of docusate.
• Intestinal obstruction, symptoms of appendicitis, acute abdominal pain, fecal impaction, especially in children. The use of docusate may mask the underlying problem.
• Self-medicating for longer than 7-days  (excessive use of the medication may lead to dependency).[12]