Laxatives and Antidiarrhoeal drugs Flashcards
Drugs affecting the lower GIT include?
laxatives and antidiarrhoeal medications, and specific drugs used for the treatment of inflammatory bowel disease (e.g. mesalazine) and irritable bowel syndrome (e.g. peppermint oil).
Laxatives are given to what?
Enhance the transit of food through the intestine
Bulk laxatives do what?
absorb water and increase the volume, bulk and moisture of non-absorbable intestinal contents, thereby distending the bowel and initiating reflex bowel activity.
Stool softeners do what?
act as dispersing wetting agents, facilitating mixture of water and fatty substances within the faecal mass, producing soft faeces. The faecal softening agents include docusate, liquid paraffin and poloxamer.
Stimulant laxatives do what?
promote accumulation of water and increase peristalsis in the colon by irritating intramural sensory nerve plexi endings in the mucosa. The principal stimulant laxatives are bisacodyl, sodium picosulfate and preparations of senna.
Osmotic laxatives do what?
Osmotic laxatives are not absorbed and, because they exert an osmotic effect, they increase the volume of fluid in the lumen
What do the opioid antidiarrhoeal drugs, Loperamide, diphenoxylate and codeine do?
activate µ opioid receptors in the gut wall, resulting in a reduction in secretions and inhibition of propulsive movements in the gut.
List medications known to cause constipation
Opioid analgesics (e.g., codeine, morphine)
Antidepressants (e.g., tricyclic antidepressants, selective serotonin reuptake inhibitors)
Antacids containing aluminum or calcium
Anticholinergic medications (e.g., antihistamines, certain antipsychotics)
Calcium channel blockers (e.g., verapamil, diltiazem)
Iron supplements
Diuretics (e.g., thiazide diuretics)
Anticonvulsant medications (e.g., phenytoin, carbamazepine)
Antiparkinsonian medications (e.g., levodopa, dopaminergic agonists)
Nonsteroidal anti-inflammatory drugs (NSAIDs)
List non-pharmacological causes of constipation
Inadequate fiber intake
Insufficient fluid intake
Sedentary lifestyle/lack of physical activity
Ignoring the urge to have a bowel movement (withholding stool)
Delayed or disrupted toilet routine
Stress and psychological factors
Hormonal changes (e.g., during pregnancy)
Aging and decreased gut motility
Certain medical conditions (e.g., hypothyroidism, irritable bowel syndrome)
What nonpharmacologic strategies would you recommend for constipation?
Increase dietary fiber (fruits, vegetables, whole grains, and legumes)
Hydration: Ensure an adequate fluid intake, preferably water, throughout the day to soften stools and prevent dehydration, which can contribute to constipation.
Physical activity: Engage in regular physical activity to stimulate bowel movements and improve overall gut motility.
Establish a regular toilet routine: Create a consistent daily routine
Respond to the urge to defecate: Avoid delaying or ignoring the urge to have a bowel movement.
Reduce stress: Implement stress-reducing techniques such as relaxation exercises, meditation, or engaging in activities that promote mental well-being
Lifestyle modifications: Ensure a healthy lifestyle by maintaining a balanced diet, managing weight, and avoiding excessive alcohol and caffeine intake, as these factors can impact bowel function.
Bulk forming laxatives should be taken with sufficient fluids, what is the reason for this?
Bulk-forming laxatives, such as psyllium husk or methylcellulose, should be taken with sufficient fluids because they work by absorbing water and increasing the bulk of the stool. Additionally, adequate fluid intake is necessary to prevent the bulk-forming laxative from causing an obstruction in the esophagus or gastrointestinal tract.
Bulk forming laxatives are considered the least harmful of the various available laxatives, why is this?
Bulk-forming laxatives are considered the least harmful among laxatives because they work naturally by adding bulk and moisture to the stool, mimicking the effects of dietary fiber. They do not stimulate the bowel or cause dependency, unlike other types of laxatives.
Why is there a risk of electrolyte imbalance in patients using osmotic and saline laxatives long term?
There is a risk of electrolyte imbalance in patients using osmotic and saline laxatives long term because these laxatives work by drawing water into the intestines, leading to increased fluid content in the bowels. Prolonged use can result in excessive fluid loss and electrolyte imbalances, particularly with laxatives that contain magnesium or phosphate.
What is the primary site of action of Stimulant laxatives and what are the resulting adverse effects?
The primary site of action for stimulant laxatives, such as bisacodyl, is the colon. They work by directly irritating the intestinal lining, increasing intestinal motility and promoting bowel movements.
Adverse effects of stimulant laxatives can include abdominal cramps, diarrhea, and excessive bowel movements. Prolonged or excessive use of stimulant laxatives can lead to dependence, electrolyte imbalances, and damage to the intestinal lining.
Why should Bisacodyl not be crushed or chewed?
Bisacodyl should not be crushed or chewed because the enteric coating of the tablets is designed to protect the medication from the stomach’s acidic environment. The enteric coating allows the tablet to pass through the stomach intact and ensures it dissolves and becomes effective in the intestines. Crushing or chewing the tablet can bypass the enteric coating and lead to the medication being released and potentially causing irritation or adverse effects in the stomach.
