Constipation Flashcards
Evaluation of constipation
- Check rx meds (opioids, anticholinergics, TCAs, CCBs, Parkinson’s drugs, antipsychotics)
- Check OTC meds (antacids, calcium, iron, etc)
- Check Red Flags
Treatment options for “acute/subacute” constipation
- Bulk Laxatives (OTC, soluble fiber)
- Stool Softeners (OTC)
- Saline Laxatives (OTC)
- Stimulant Laxatives (OTC)
- Hyperosmolar Laxatives
- Lubricant Laxatives
- Suppositories
- Enemas
- Perineal self-acupressure
Bulk Laxatives
- Wheat dextrin, psyllium, methylcellulose, polycarbophil
- Speed up colonic transit
- Titrate up, mild to mod constipation** –> make take 3 days to work
- Take w 8 oz water**
- NOT helpful in OIC
- Avoid if obstructive sx, dysphagia, frail/bedbound**
Stool Softeners
- Docusate
- increase peristalsis
- Not effective when used alone**
Saline Laxatives
- Magnesium hydroxide
- Hyperosmolar agent that results in increased peristalsis
- Hypermag may occur in CKD
Stimulant Laxatives
- Bisacodyl*, Senna, Castor Oil
- Alter lyte transport and stimulant myenteric plexus to increase motility
Hyperosmolar Laxatives
Lactulose
- Hepatic Encephalopathy**: alters ammonia concentration
- Constipation: produced osmotic effect in colon –> distention and peristalsis–> poorly tolerated
Polyethylene Glycol (PEG 3350)
- Crystalline powder
- MOA: induced catharsis by strong lyte and osmotic effects (inc intraluminal fluid)
Lubricant Laxatives
- Mineral oil
- MOA: eases passage of stool by inhibiting reabsorption of water
- Malabsorption of fat-soluble vitamins possible with prolonged use**
Suppositories
- Glycerin and Bisacodyl
- Induce evacuation by local rectal stimulation
Enemas
- Mineral oil, tap water, sodium phosphate, soap suds
- Evacuation induced by distended colon and mechanical lavage
Which constipation treatments should you avoid in neutropenic or thrombocytopenic patients?***
suppositories and enemas
Perineal self-acupressure
-2 fingaaaas to areas between anus and scrotum/vagina when the perceive urge to defecate
Chronic Idiopathic Constipation (CIC)
- More common in elderly and women
- Infrequent BMs (<3x/wk)
- Straining
- Lumpy/hard stool
- Sensation of anal blockage or incomplete evac
- Need for manual maneuvers to aid in defecation
Lubiprostone
- MOA: PG metabolite that acts locally in GI to open Cl channels on luminal surface of GI–> dec transit time
- Indications: CIC, IBS-C, OIC for non-cancer
- CI: pts with known or suspected mechanical obs and mod/severe gastroparesis**
- ADRs: dose-dependent nausea and diarrhea
Linaclotide, Plecanatide
- MOA: guanylate cyclase-C receptor agonist
- Indications: CIC, IBS-C
- Pearls: mildly effective**, BBW < 18 (death), CI with obstruction
- ADRs: GI intolerance
Prucalopride
- MOA: selective serotonin agonist–> stimulate secretions and transit
- Indications: CIC (modestly effective)
- CI: perf, obstruction, ileus, IBD
- ADRs: HA, N/D, abd pain
Constipation Rec for “Regular Outpatient”
- Step 1: dietary/supplemental fiber PLUS water AND exercise in most pts (not OID, frail, bed ridden, kids)
- Step 2: Add stimulants or PEG** if above measures don’t work
- **OTC products under very similar names may have different active ingredients
Constipation Rec for “Hospitalized/Opiate”
- Historic rec: Stool softener PLUS stimulant for OIC
- Newer rec: PEG–> start when opiate is started, prevention is key!
Methylnaltrexone
- MOA: selective mu-opioids receptor antagonist
- Indications: OIC in pts w advanced illness* receiving palliative care*; OIC in pts taking opioids for chronic noncancer pain**
- ADRs: N/D, abd pain, CI in obstrcution
Naloxegol
- MOA: pegylated version of naloxone, pegylation minimizes naloxegol crossing BBB
- Indications: OIC in NON-CANCER pts
- Interactions: 3A4 sub
- ADRs: N/V, abd pain, withdrawal sx possble, CI in obs
Naldemedine
- MOA: Naltrexone derivative–> blocks opioid stimulation of mu receptor in GI tract
- Indications: OIC in NON-CANCER pts
- Interactions: 3A4 sub
- ADRs: N/V, abd pain, withdrawal sx possible, CI in obs
Constipation in Pregnancy
- 1st line = fluids, fiber, exercise–> add bulk laxatives slowly if conservative tx fails
- PEG- C
- Lactulose- B
- Magnesium hydroxide- no data
- Bisacodyl»_space; Senna- C
- Docusate- C (contained in some prenatal vitamins*)
- Mineral Oil- C
- Castor Oil- X
Constipation in children
1) Disimpaction manually or pharm (more common)
2) Maintenance- dietary recs, same meds as adults
Constipation in children step-wise
1) Disimpaction w oral PEG»_space; enema or digital disimpaction
2) Fluids and fiber
3) Maintenance: PEG»_space; MOM, lactulose –> tx for at least 6 months
