Colonoscopy: It's All in the Preparation

Josephine Aranda, PharmD

Disclosures

October 07, 2015

Question

How can pharmacists help in preparing patients for a colonoscopy?

Josephine Aranda, PharmD
Adjunct Clinical Instructor, School of Pharmacy, Northeastern University, Boston, Massachusetts; Pharmacy Resident, Adult Medicine, The Dimock Center, Roxbury, Massachusetts

Colorectal cancer is the third leading cancer and the second most common cause of cancer-related death.[1]

Although there are newer, less invasive colorectal cancer screening methods, such as guaiac and immunochemical-based fecal occult blood testing, colonoscopy allows examination of the entire colon with high sensitivity and specificity and allows for concurrent biopsy or polypectomy, if necessary.[2]

Guidelines recommend colonoscopy every 10 years beginning at age 50 years and continuing through age 75 years; 90% of colorectal cancers occur in people aged 50 years or older.[3,4] A colonoscopy may be recommended sooner or more frequently for patients with a family history of colorectal cancer or for those with inflammatory bowel disease.[2,3,4]

Inadequate bowel preparation for colonoscopy is associated with increased procedure time, complications, and risk for undetected precancerous lesions.[5,6] The common factors for inadequate preparation include failure to complete the full volume of laxative owing to poor tolerability or compliance, diabetes, frequent constipation, and older age.[6,7]

Pharmacists can help by counseling patients about the importance of colorectal cancer screening and what to expect before and during the procedure, and proactively screening for necessary medication changes.

Bowel Preparation

Bowel cleansing requires dietary modifications and laxatives (Table). About 3 days before a colonoscopy, a low-fiber diet is recommended, followed by a clear liquid diet 1 day before and no fluids at least 2 hours before.[8]

When counseling patients on laxative regimens, pharmacists can advise on improving palatability, maintaining adequate hydration, and planning for frequent bowel movements.

Table. Common Bowel Cleansing Agents [8,9,10,11,12]

Agent Dosing Minimum
Total
Recommended
Fluid
Mechanism
of
Action
Side
Effects
Tolerability Clinical
Relevance
Stimulant
Senokot®a (senna) Used adjunctively, and typically as a single dose Stimulates the intestinal mucosa, causing muscle contractions and stool movement Nausea, vomiting, cramping, and electrolyte imbalances May be harsh on the intestinal mucosa When used with PEG or hyperosmotic solutions, can help decrease fluid volume requirements
Dulcolax®a (bisacodyl)
Prepopik® (sodium picosulfate, magnesium oxide, citric acid) 2-day regimen (preferred)
Day before procedure:
5 oz, plus 40 oz clear liquids
Procedure day: 5 oz, plus 24 oz clear liquids


1-day regimen
Day before procedure:
5 oz, plus 40 oz clear liquids in PM or early evening; followed by 5 oz plus 24 oz clear liquids 6 hours later
10 oz, plus 2 L fluid Avoid in patients with renal impairment
Hypoosmotic
MiraLAX®,a
238 g (PEG without electrolytes)
Varied regimens, eg 238 g in 2 L sports drink

Split dose
Day before and procedure day: 1 L

Single dose
Day before procedure: 2 L
2 L fluid Nonabsorbable solution that cleanses the bowel through ingestion of large volumes of mixture with sports drinks Nausea, bloating, cramping, and electrolyte imbalances Less volume than some other PEG-based regimens Avoid in patients with renal impairment, gastric retention, bowel perforation, or gastrointestinal obstruction
Isoosmotic
GoLYTELY®
CoLyte®
Split dose
Day before procedure: 2-3 L Procedure day: 1-2 L

Single dose
Day before procedure: 4 L
4 L Nonabsorbable electrolyte solution that causes bowel cleansing with ingestion of large volumes of fluid Nausea, vomiting, bloating, and abdominal fullness





Lower incidence of electrolyte imbalances
4-L regimens least tolerable of all agents, owing to large volume needed


May add flavor pack, lemon juice or a powdered beverage (eg, Crystal Light®, Kool-Aid®; not red, blue, or purple) to counteract saltiness


Storing in the refrigerator before ingestion or drinking with a straw may improve tolerability
Preferred in patients with renal impairment, heart failure, inflammatory bowel disease, or advanced liver disease with ascites

Avoid in patients with gastric retention, bowel perforation, or gastrointestinal obstruction.


Avoid MoviPrep in patients with glucose-6-phosphate dehydrogenase deficiency
NuLYTELY®
TriLyte® (sugar-free)
4 L
HalfLytely
(PEG/bisacodyl)
MoviPrep
(PEG/ascorbic acid)®
Split dose
Day before and procedure day: 1 L

Single dose
Day before procedure: 2 L
2 L
Hyperosmotic
Magnesium citrate,a Split dose.
Day before and procedure day: 10-15 oz with 2 L fluid
20-30 oz plus 2 L fluid Hyperosmotic effects cause fluid retention in the bowel, resulting in peristalsis and bowel cleansing. Nausea, vomiting, headache, bloating, abdominal pain, and electrolyte imbalances Less volume and more tolerable than some PEG-based regimens


Refrigerate to improve palatability
Not routinely recommended


Avoid in patients with renal impairment, heart failure, advanced liver disease, electrolyte imbalances, and gastrointestinal obstruction


Use caution in elderly patients
Visicol® OsmoPrep®, 32 tablets (sodium phosphate) with 3.4 L fluid Split dose
Day before procedure: 20 tablets with 1 L fluid
Procedure day: 12 tablets with 1 L fluid
2 L Less volume and more tolerable than some PEG-based regimens Not routinely recommended


Avoid in patients with renal impairment or those with increased risk for acute phosphate nephropathy
SuPrep®, 12 oz (sodium, potassium, magnesium sulfate) with 2 L fluid Split dose
Before and day of procedure: 6 oz with 10 oz water plus 32 oz fluid
12 oz
plus 2.5 L fluid
Hyperosmotic effects cause fluid retention in the bowel, resulting in peristalsis and bowel cleansing;
Suclear also contains PEG
Nausea, vomiting, headache, bloating, abdominal pain, and electrolyte imbalances May add flavor pack, lemon juice, or a powdered beverage (eg, Crystal Light, Kool-Aid; not red, blue, or purple) to counteract saltiness

Storing in the refrigerator before ingestion or drinking with a straw may improve tolerability
Avoid in patients with gastric retention, bowel perforation, or gastrointestinal obstruction
Suclear®,6 oz (sodium, potassium, magnesium sulfates, PEG) Split dose
Day before procedure: 6 oz sulfates with 10 oz water, plus 32 oz fluid Procedure day: 2 L PEG

Single dose
Evening before procedure: 6 oz sulfates with 10 oz water, plus 16 oz fluid; 2 hours later, 2 L PEG plus 16 oz fluid
6 oz plus 2 L PEG, plus 1.25 L fluid

PEG = polyethylene glycol
aAvailable over-the-counter.

Medication Management

Most prescription and over-the-counter medications may be safely continued before colonoscopy; however, recommendations to withhold medications may vary among gastroenterologists.

  • Iron supplements should be stopped 7 days before colonoscopy. Iron can turn stool dark and tarry, which can impair visualization during the procedure.[13,14]

  • Patients taking insulin and sulfonylureas are at increased risk for hypoglycemia and may need closer monitoring or medication adjustments.[13,14]

  • Recommendations to hold antiplatelets or anticoagulants are based on the risk of the procedure (eg, with or without polypectomy) and clinical indication (eg, ischemic heart disease with or without coronary artery stents).[15]

  • Some gastroenterologists may advise against nonsteroidal anti-inflammatory drugs (eg, ibuprofen) and aspirin, although continuation is generally safe.[16]

The Pharmacist's Role

Although colonoscopy can be life-saving, with its improved rates of early colorectal cancer detection and treatment, preparation is often unpleasant and daunting.

Pharmacists can counsel patients on diet and laxative regimens for bowel preparation and emphasize the importance of adherence. Furthermore, pharmacists can screen for high-risk medications or conditions that may necessitate temporary medication changes or selection of an alternative laxative.

Acknowledgment: The author wishes to acknowledge the assistance of Sana Ahmed, PharmD Candidate 2016; Dayna LeSueur, PharmD Candidate 2016; and Debra Reid, PharmD, BC-ADM, CDE, BCACP, at Northeastern University, School of Pharmacy, in collaboration with The Dimock Center, Boston, Massachusetts.

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....