Continuing Education Activity

Docusate is a medication used in the management and treatment of constipation. It is in the stool softener class of drugs. This activity reviews the indications, action, and contraindications for docusate in the treatment and management for constipation. This activity will highlight the mechanism of action, adverse event profile, and other key factors (e.g., off-label uses, dosing monitoring, relevant interactions) pertinent for members of the interprofessional team in the care of patients with constipation and related conditions.

Objectives:

• Describe the mechanism of action of docusate in patients with constipation.
• Identify the contraindications/precautions to using docusate.
• Outline the indications for docusate use in routine clinical practice.
• Review the role of interprofessional communication between the patient and physician regarding education, prevention, and medication (including docusate) use in case of constipation.

Indications

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] 

Mechanism of Action

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]

Administration

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]

Adverse Effects

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

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]

Monitoring

Excess use of docusate may cause dependence on bowel function. The patients with anorexia nervosa, bulimia, or the elderly that use the laxatives for constipation are at risk for dependency and abuse. Alternating diarrhea with constipation can be a presentation in laxative abuse.  Excessive bowel movements induced by a laxative can lead to fluid and electrolyte losses via the gastrointestinal tract. This condition can manifest with hypokalemia, hypomagnesemia, and non-anion gap metabolic acidosis. Hypovolemia can lead to acute kidney injury. The treatment of laxative abuse is to stop the offending agent. Rebound signs and symptoms like constipation, weight gain, and edema can occur after stopping a laxative. Diuretics can be used cautiously in such cases to treat edema.[6][16][17][18]

Toxicity

Docusate has been in use in the U.S. since the 1950s. It has a well-documented safety and tolerability profile.

Docusate undergoes metabolism in the liver and undergoes extensive first-pass metabolism to both active and inactive metabolites. Despite its hepatic metabolism and high plasma protein binding, there are no drug-drug interactions or reports of clinically apparent hepatoxicity.[19]

Enhancing Healthcare Team Outcomes

Constipation is one of the most common complaints in outpatient clinics and hospitalized patients. The patients may present with symptoms of nausea vomiting, abdominal pain, or urinary retention. The causes of constipation may be due to a myriad of underlying diagnoses, including neurological, metabolic, obstructing lesions of the gastrointestinal tract, including colorectal cancer and endocrine-related problems such as diabetes or hypothyroidism. Psychiatric disorders such as anorexia nervosa can also contribute to constipation.  Inadequate amounts of fluid and fiber intake are risk factors for developing constipation. 

A primary care physician may initially encounter and manage most cases of constipation. However, referral to a  sub-specialist may be required in some cases, depending on the underlying cause, as noted above. The involvement of a surgeon, gastroenterologist, neurologist, psychiatrist, or an endocrinologist can be necessary. A radiologist can provide valuable information through imaging studies about bowel pathology by collaboratively working with a physician or a surgeon. A dietician plays a vital role in modifying dietary risk factors. The pharmacist will ensure that the patient is not on any medication that can worsen constipation and suggest appropriate alternatives. The nurses are critical members of the interprofessional group as they are involved in direct patient care, education, and counseling both in the outpatient and hospital setting.

Overall, interprofessional care coordination by physicians, nurses, pharmacists, and dieticians is vital in improving patient experience and outcomes.