lower GI- constipation Flashcards
(34 cards)
normal BM frequency
=< 3 a week
causes of constipation
low activity, low fiber, low carbs, low fluid intake, meds, cheese, putting off urge
most constipating antacids
Al, then Ca
Mg loosens stools, Al/Mg usually balance each other out
notable constipating meds
opioids, Al/Ca antacids, anti-cholinergics
bulk laxatives onset
12-72 hours
stimulant laxatives onset
6-12 hours
saline laxatives
30 min-3 hours
surfactant laxatives
24-72 hours
lubricant laxatives
6-8 hours
hyperosmotic laxatives
15 min-1 hour
bulk laxatives MOA
- Nonabsorbable; expand and take up water; stimulate distension reflex and intestinal motility
- good first choice, safest to use
bulk laxatives contraindications
GI obstruction
bulk laxatives caution in:
- diabetics (has a lot of sugar)
- GI obstruction
bulk laxatives types
polycarbophil, psyllium, methylcellulose
stimulant laxatives MOA
- local irritation of intestinal tract, increase peristalsis, increase fluid secretion (usually the colon is an absorptive organ, this makes it secrete fluid instead)
- Generally, not laxative of first choice
stimulant laxatives warnings
- casual use discouraged
- overuse damages physiologic neurologic colon function, becomes dependent on it
- “cathartic colon”
stimulant laxatives types
senna, sennasides, castor oil, bisacodyl
saline laxatives MOA
- High concentration of electrolytes - hypertonic state - osmotic gradient - draws water into colon - increased colonic pressure - stimulates movement
- Single dose or short term use
saline laxatives warnings
CHF, HTN, renal failure
saline laxatives types
- Phillips Milk of Magnesia
- Fleet Phospho-Soda
- Magnesium Citrate
surfactant laxatives are actually
surfactants/emollients
surfactant laxatives MOA
- Mild - increase fluid secretion, “wetting” agents; lowers surface tension, allowing water into fecal mass.
- Prevention rather than treatment
surfactant laxative types
docusate
docusate dose
100 mg is a placebo, use 250 mg
