Mock Exam Questions Flashcards
(5 cards)
Delilah calls back a few weeks later and reports the tablets worked well (travacalm). Her neighbour wants to go fishing out on a boot soon. Her neighbour said she takes avomine(promethazine theoclate 25,g) instead of kwells (hyoscine hydrobromide 300mcg) and delilah is wondering if she should try avomine next time. Compare and contrast the mechanism of actions of hyoscine hydrobromide and promethazine and provide a recommendation considering delilahs medical history
- delilah has a history of seizure
MOA of hyoscine hydrobromide: tertiary amine anticholinergic that blocks muscarinic actions of acetylcholine in the vestibular area (area of brain and ear). Other effects include reduction of secretions including saliva, urine; inhibition of gastric motility; increased bladder capacity, tachycardia, bronchodilation.
MOA of promethazine: sedating antihistamine binding to H1 receptors and inactivating them including in the vestibular system. Reduces smooth muscle contraction, vasodilation, stimulation of sensory nerves (causes itch). Also, a dopamine antagonist in the CTZ reducing nausea and vomiting. Crosses the BBB and exhibits anticholinergic effects.
Recommendation: Both medications can be used for motion sickness however promethazine lowers the seizure threshold so hyoscine hydrobromide would be the preferred ooption for delilah with a history of seizure.
Discuss the MOA of sedating antihistamines (promethazine and pheniramine), common adverse effects and their use in children.
MOA of sedating antihistamines: Act on histamine H1 receptors to block effects of histamine, results in reducing smooth muscle contraction, vasodilation, and stimulation of sensory nerves. Sedating antihistamines also exhibit anticholinergic activity thereby reducing secretions including saliva, bronchial secretions, and fecal secretion. They cross the BBB.
Adverse effects of sedating antihistamines: Crosses the BBB so can cause drowsiness and central nervous system depression, as well as CNS adverse effects such as delirium, confusion. They can cause constipation, urinary retention, tachycardia, and dry mouth
Summary and recommendation for use in a 20-month-old child: Not safe for use in children under 2 years old due to risk of CNS depression and higher chance of adverse ffects including derilium, confusion and hallucinations
Compare and contrast the pharmocological actions of aspirin vs paracetamol and codeine combination in migraines and provide a recommendation
Already know aspirin and paracetamol
Codeine: an opiate analgesic acting on mu-opioid receptors in the brain and spinal cord, resulting in opening potassium channels and inhibiting the opening of voltage-gated calcium channels, leading to decreased neuronal excitability and reduced transmitter release and neurotransmission of pain messages to the CNS
Recommendation: Paracetamol and aspirin are first-line agents in migraine. Both provide analgesic relief. Codeine is not recommended as first line management in headaches such as migraine due to risk of medication overuse headache, and increased risk of nausea and vomiting and reducing absorption of other medications used in migraine. codeine-containing analgesics, not available OTC, need to be referred to a doctor
Compare and contrast the MOA of sumatriptan and metoclopramide, their adverse effects and summarise their use in migraine
MOA of sumatriptan: Vascular 5HT1 receptor agonist, found mostly in the cranial and trigeminal nerve. Actions mediate vasoconstriction of large arteries and inhibit trigeminal nerve transmission.
Adverse effects of sumatriptan: Transient burning or irritation in nose/throat, taste disturbance, rebound headache
MOA of metoclopramide: dopamine D2 receptor antagonist in the chemoreceptor trigger zone in the central nervous system. Acts as 5HT-4 receptor agonist in the enteric nervous system to increase gastric motility and therefore gastric emptying. It crosses the BBB so can experience CNS adverse effects
Adverse effects of metoclopramide: Drowsiness, dizziness, headache
Summary of use in migraine: Metoclopramide is used for nausea associated with migraine whereas sumatriptan is used as a second-line agent to act on the early mechanisms to manage the migraine. sumatriptan is only available on prescription and usually considered by a doctor if the patient is not responding to first line treatment on three consecutive occasions
Compare and contrast the mechanism of action of lactulose vs docusate and senna and considerations in pregnancy
MOA of lactulose: Osmotic laxative draws fluid and increases pressure in the lumen of the bowel to stimulate peristalsis and evacuation of the bowel. Metabolized in the colon to low molecular weight acids, decreasing pH of bowel contents enhancing its laxative properties.
MOA of docusate and senna: Docusate is a surfactant stool softening laxative working to soften stools by facilitating the mixing of water with fecal matter. Work to increase the secretion of intestinal fluids. Senna is a stimulant laxative that increases GI motility by stimulating the colonic nerve ending.
Recommendation: Lactulose is safe to use in pregnancy. Although senna is category A, stimulant laxatives should be avoided in pregnancy
