Constipation Flashcards
name four groups of people at risk of constipation?
Elderly- reduced colonic motility
reduced mobility
reduced fluid intake
possible polypharmacy which may lead to increased side effects e.g opioids/ channel blockers, diuretics|)
people using opioids- reducing peristalsis due to opioids binding to opioid receptor
increasing water absorption- harder stool
people using opioids may be street homeless- avoiding the call to stool.
pregnant women. gut transit time is reduced due to progesterone levels relaxing the smooth muscle in the gut. Pressure from growing uterus on stomach/ intestines.
Neurological conditions can inpair the utonomic nervous system control over bowel movements leading to reduced colonic mobility and weaker defacation reflexes . also for example in stroke patients reduce mobility and an altered diet can increase risk of constipation.
Can you identify 3 different classes of laxative and provide an example of each?
Stimulants – Senna, Bisacodyl
Bulk-forming agents – Bran, spatula husk
Osmotic laxatives – Lactulose
Stool Softeners – Glycerine suppositories
Name four groups of people at risk of nausea and Vomiting and give rationale.
Patients receiving chemotherapy and radiotherapy.
chemoreceptors trigger zone in the brain activated and gut mucosa damaged causing irritation stimulating serotonin and vomiting.
post-operative patients. general anaesthetics and opioids depress the central nervous system and trigger the chemoreceptor trigger zone leading to postoperative nausea.
people with migraine- Dopamine and serotonin deregulation can trigger the chemoreceptor trigger zone and lead to vomiting. Hypersensitivity to light, sound and smell further worsens the sensation.
Can you identify 3 classes of antiemetics and give an example of each?
Dopamine D2 Antagonist - metoclopramide
(blocks d2 receptor in cuz reducing D and V)
5-H23 Serotonin Antagonist- Ondansetron
(blocks HT3 Receptor in gut)
H1 Antihistamine - Cyclizine
Describe the Mechanism of Action of aminoglycoside antibiotics
- Binds to bacterial ribosomes
works because of differences between ribosome size in human and bacterial cells
30S / 50S ribosomal subunit
inhibiting protein synthesis
This results in a decrease in bacterial cellfunction
E.G Gentamicin
Describe the action of Sulphonamide antibiotics
inhibit the bacterial folic acid synthesis
blocking dihydropteroate
prevents the production folic acid
necessary for dan/RNA synthesis.
they compete as Paba analogs for enzyme binding sites leading to bacteriostatic effects,
e.g Trimethropin
Describe the action of the B-lactum group of antibiotics?
Attaches to penicillin-binding protein on cell wall
inhibits the formation of bacterial proteins on the cell wall
this makes cell walls weak
Primarily work during cell replication
Are bactericidal meaning they kill bacteria
e.g Ampicillin
