Management of Constipation

Classification and Initial Assessment

Constipation can be classified into three main categories: normal transit constipation, slow transit constipation, and defecatory disorders 2
Secondary causes of constipation include medications, metabolic disorders, neurological conditions, and structural abnormalities 2, 3
Opioid-induced constipation affects approximately 50% of patients with advanced cancer and most patients treated with opioids 4
Assessment should include questions about stool frequency, consistency, straining, sensation of incomplete evacuation, and need for manual maneuvers 3, 5
Physical examination should include abdominal examination, perineal inspection, and digital rectal examination 3, 5

Lifestyle modifications and fiber supplementation should be the first-line approach for most patients with chronic idiopathic constipation 1, 2, 3
Key lifestyle factors include ensuring privacy and comfort during defecation, proper positioning, increased fluid intake, and increased physical activity within patient limits 3, 5
Fiber supplementation with psyllium has the strongest evidence, targeting 20-30g of total dietary fiber daily 1, 2
Adequate hydration should be encouraged with fiber use, and flatulence is a common side effect 1

Osmotic laxatives, such as polyethylene glycol (PEG), are recommended when fiber is insufficient 3, 5
Stimulant laxatives, such as senna and bisacodyl, are also effective and should be prescribed prophylactically for opioid-induced constipation 3, 4, 5
Suppositories and enemas are preferred first-line therapy when digital rectal examination identifies a full rectum or fecal impaction 3, 5

Management involves digital fragmentation and extraction of stool, administration of glycerin suppositories or enemas, and implementation of a maintenance bowel regimen 7
Contraindications for enemas include neutropenia, thrombocytopenia, intestinal obstruction, recent colorectal surgery, severe colitis, and recent pelvic radiotherapy 5

Secretagogues, such as lubiprostone and linaclotide, enhance intestinal fluid secretion and are effective for chronic idiopathic constipation 4
Peripherally acting μ-opioid receptor antagonists (PAMORAs), such as methylnaltrexone and naloxegol, are recommended for opioid-induced constipation 4, 5

Elderly patients have a higher prevalence of constipation and require special attention, including ensuring access to toilets, providing dietetic support, and optimizing toileting 3, 5
Individualizing laxative therapy based on comorbidities and potential drug interactions is crucial, and PEG offers an efficacious and tolerable solution with a good safety profile 5