Pharmacology Cases Flashcards
How does HIV virus effect the NS?
- Neuropathy
- Affects parasympathetic nerves more than sympathic
- Therefore, symptoms of excess SNS tone will be observed
How does the fact cardiac B adrenoreceptors decrease with age affect the effect of B-blocker drugs?
- Decrease the effectiveness (increased noradrenaline, so competition for the B-receptor is increased)
- Blood pressure also becomes less sensitive to treatments involving heart rate
How would lower plasma proteins with age affect the effect of beta blockers?
- Increased bioavailability
- This is because a smaller proportion of the b-blocker will be bound to the plasma proteins
How would decreased GI blood flow in old age affect the effect of beta blockers?
- Reduced drug absorption, so therefore effectiveness would decrease (this could be solved by administering injections)
- If the drug were lipid soluble then the effect of this would decrease
How does decreased total body water in old age affect the effect of beta blockers?
- Loss of skeletal muscle causes reduced water
- If the drug is water soluble then it will be more effective, as the concentration of the drug in the blood will be increased at the same dose
- If the drug is lipid soluble then it will be less effective as more of the drug will dissolve into the adipose
How will decreased renal blood flow in old age affect the effect of beta blockers?
- Reduced excretion of the drug
- Less beta blockers will reach the kidney
- Increased renin production would increase the effect of the beta blocker
How does ritanovir affect the metabolism of some drugs?
- Acts as a 3A4 cytochrome inhibitor
- This results in decreased metabolism of drugs that are metabolised by this enzyme
Why do you have to eat when taking some tablets?
- These drugs irritate the stomach lining, causing nausea
- The drug will also be absorbed over a longer period of time (as it is released from the stomach in a pulsatile form)
What is normal cholesterol?
Below 5.2mmol/l is desirable
What affects the half life of lipid soluble drugs?
- The amount of fat
- Lipid soluble drugs will deposit in the adipose tissue, and be released slowly
- Look at the patient with the highest % body fat AND consider weight to ensure they have the most fat
When is blood pressure considered high?
When it is over 140/90mmHg
What is the first line treatment for hypertension?
- Younger than 55 Ace inhibitors or angiotensin receptor blockers
- Over 55 or afro-caribbean calcium channel blocker/ thiazide like diuretic
What is the second step in hypertension treatment?
- Ace inhibitor and calcium channel blocker
- Or ace inhibitor and thiazide type diuretic
What is the third step in hypertension treatment?
- Combination of ace inhibitor and angiotensin receptor blocker wit calcium channel blocker and thiazide like diuretic
What is the fourth stage of hypertension treatment (resistant hypertension?)
- Low dose spironolactone
- Alpha blocker or beta blocker
