Drug Of The Day Flashcards
What is the drug class of amlodipine?
Dihydropyridine calcium channel blocker. Dihydropyridines are selective for peripheral vasculature smooth muscle and have little effect of the heart.
Common indications for amlodipine?
For reducing hypertension as cause peripheral vasodilation. Primary choice anti-hypertensive in low renin patients (African-Caribbean)
What is the mechanism of action of amlodipine?
CCBs target calcium initiated smooth muscle contraction. Interacts with alpha-1 subunit of VOCC in the membrane of vascular smooth muscle cells. Has little action of VOCC of cardiac myocytes.
Important adverse drug effects of amlodipine?
Ankle swelling, flushing, headaches due to vasodilation
May get palpitations (compensatory tachycardia - this is more likely in CCBs that have a greater chronotropic affect.
Important drug-drug interactions of amlodipine?
Amlodipine interacts with simvastatin, reducing the metabolism of the statin and maintaining its levels in the body. Need to reduce dose of simvastatin if taken together.
What is the drug class of losartan?
Losartan is an angiotensin II receptor blocker (ARB/AT1 - receptor blocker)
What are common indications for losartan?
To reduce blood pressure in hypertension, less effective in low renin patients (African/Caribbean)
Most effective drug at treating hypertension due to excessive activation of RAAS.
What is the mechanism of action of losartan?
Act as antagonists of angiotensin 2 at AT1 receptors, stopping vasoconstriction. Also stops the stimulation of aldosterone release from the adrenal glands and therefore reduces circulating fluid volume, water reabsorption through the effects of ADH and feelings of thirst. Only act by decreasing the effect of AT2 - no effect on bradykinin.
Important adverse drug effects of losartan?
Hypotension, hyperkalaemia due to decreased aldosterone, cause of worsen renal failure
important drug-drug interactions of losartan?
Drugs that increase potassium (spirolactone)
NSAIDS
What class of drug is indapamide?
Thiazide like diuretic
What are common indications for indapamide?
Hypertension
Hyperkalaemia
Hypocalcaemia
-useful over CCB in oedema
What is the mechanism of action of indapamide?
Inhibit the ;a/Cl co-transporter in the DCT. Decrease sodium and water reabsorption but RAAS compensates over time. Long term affects on sensitivity of vascular smooth muscles to vasoconstrictors (calcium/noradrenaline).
Important adverse drug reactions of indapamide?
Hypokalaemia Hyponatraemia Hyperuricaemia (gout) Arrhythmia Increased glucose Increased cholesterol and triglycerides
Important drug-drug interactions of indapamide?
NSAIDS
Potassium lowering drugs such as loop diuretics.
When used with beta blockers glucose reabsorption increased.
Why is it recommended to take indapamide first thing in the morning and not before bed?
As thiazide like diuretics act within one or two hours, rapid diuresis often occurs in the first few doses but is less noticeable with continued treatment. Taken in the morning to minimise nocturia.
What drug class is Atorvastatin?
A statin
What are the common indications for atorvastatin?
CVD prevention
- Primary prevention- 20mg of atorvastatin once daily if there is a 10 year CVD risk of greater than 10% using QRISK
- secondary prevention - 80mg atorvastatin once daily
LDL cholesterol lowering
What is the mechanism of action for atorvastatin?
Statins have competitive inhibition of HMG-CoA reductase (rate controlling enzyme in the HMG-CoA to mevalonate pathway.)
Contributes to the upregulation of hepatic LDL receptors, increasing the clearance of LDL.
What are the adverse drug reactions of atorvastatin?
GI disruption, nausea, headache
Myalgia
Rhabdomyolysis
Increased liver enzymes
What are the important drug-drug interactions of atorvastatin?
CYP 3A4 important – amiodarone, diltiazem, macrolides - increases [plasma] statin
Amlodipine (CCB) also increases [plasma] statin
What is the difference between high dose and low dose atorvastatin offered to patients?
Low dose is used in primary prevention of CVD = 20mg of atorvastatin daily
High dose is used in secondary prevention of CVD when the patient has already had a major CVD event = 80mg of atorvastatin once daily.
What drug class is spironolactone?
A aldosterone (mineral corticoid ) receptor antagonist.
What are the common indications of spironolactone?
As step 4 in treating hypertension is step 3 (treatment with ACEi or ARB + CCB + Thiazide like diuretic) hasn’t corrected hypertension
What is the mechanism of action of spironolactone?
Blocks the aldosterone receptor in the collecting duct. ENAC channels and ROMK channels are not expressed. More sodium and therefore water lost in urine. Spironolactone is not highly selective and may affect other steroid receptors ( such as the testosterone receptor ) and cause adverse effects.
What are the adverse drug reactions of spironolactone?
Hyperkalaemia
Gynecomastia
What are the important drug-drug interactions of spironolactone?
Drugs that increase potassium levels
Pregnancy
Why is adherence of spironolactone a particular challenge, especially in men?
As can block the testosterone receptor causing challenging symptoms such as gynaecomastia and symptoms associated with androgen deficiency such as decreased sex drive/erectile dysfunction/loss of body hair.
What drug class is metformin?
Biguanide
What are the common indications of metformin?
First line choice for treatment of T2DM (HbA1c over 48mmol/mol)
What is the mechanism of action of metformin?
Decrease hepatic glucose production by inhibiting gluconeogenesis. Some gluconeogenic activity remains so hypoglycaemia risk is reduced.
Suppresses appetite so limits weight gain
What are the adverse effects of metformin?
GI upset, nausea, vomiting, diarrhoea
What are the important drug-drug interactions of metformin?
ACEi, diuretics, NSAIDs - drugs that impair renal function.
Loop and thiazide diuretics as they increase glucose reabsorption so reduce the action of metformin
What are the potential side effects of weight and glycaemic control when taking metformin?
Most treatments of T2DM result in weight gain due to the promotion of anabolic activity. As metformin suppresses appetite it limits weight gain.
Risk of hypoglycaemia is small as only partially inhibits gluconeogenesis in the liver.
What drug class is sitagliptin?
Dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors / gliptins )
What are the indications of sitagliptin?
Used is combination with metformin in the treatment of T2DM.
What is the mechanism of action of sitagliptin?
Prevents the degradation of incretin (GLP-1). Increases the plasma GLP-1 levels. Glucose dependant (to release the incretins in the first place) so postprandial action. Does not stimulate insulin release at normal blood glucose levels so have a lower hypoglycaemic risk than other treatments.
What are the common adverse affects of sitagliptin?
GI upset, small pancreatitis risk
What are the important drug-drug interactions of sitagliptin?
Other hypoglycaemic agents
Drugs that increase plasma glucose as action oppose gliptin action.
Thiazide like and loop diuretics.
How does sitagliptins mechanism of action differ from that of GLP-1 receptor agonist/incretin mimetics?
Both exert their action through the action of GLP-1 receptors.
Sitagliptin increases the amount of endogenous GLP-1 by stopping its degradation.
Incretin mimetics increase glucose dependant synthesis of insulin secretion. Act by activating the GLP-1 receptor
What drug class is gliclazide?
Sulfonylurea
What are the indication of gliclazide?
Used with a combination of other agents (metformin) in the treatment of T2DM
Used as a first line option for treatment of T2DM is metformin is contraindicated.
What is the mechanism of action of gliclazide?
Stimulate B-cell pancreatic insulin secretion by blocking the ATP-dependant K+ channels, causing membrane depolarisation.
What are the adverse effects of gliclazide?
Mild GI upset, nausea, vomiting, diarrhoea, hypoglycaemia (works at low glucose)
Weight gain through anabolic effects of insulin.
What are the important drug-drug interactions of gliclazide?
Other hypoglycaemic agents
Loop and thiazide like diuretics that increase glucose levels and so reduce the SU action
How does the action of gliclazide differ from some of the other hypoglycaemic drug classes?
Other hypoglycaemic drug classes such as biguanides and thiazolidinediones affect storage mechanisms in the body to increase anabolic or decrease catabolic reactions. Gliclazide acts by promoting insulin release, which is only possible if there is some residual pancreatic function.
What is the drug class of clopidogrel?
ADP receptor antagonist
What are the indication of clopidogrel?
Used for a wide variety of presentations where anti platelet is needed.
Mono therapy where aspirin is contraindicated.
NSTEMI patients for 3 months
STEMI patient for up to 4 weeks.
Ischaemic stroke and TIA long term secondary prevention.
What is the mechanism of action of clopidogrel?
When endothelium is damaged it releases ADP, which is detected by the P2Y12 receptor causing activation of GPIIb/IIIa receptors which results in platelet aggregation. Clopidogrel is an irreversible inhibitor of the P2Y12 receptors and stops this platelet aggregation mediated by ADP by blocking the ADP receptor
What are the adverse effects of clopidogrel?
Bleeding! GI upset - dyspepsia and diarrhoea
Thrombocytopenia
What are the important drug-drug interactions of clopidogrel?
Clopidogrel requires CYPs for activation as it is a prodrug.
CYP inhibitors - omeprazole, ciprofloxacin, erythromycin, some SSRIs need to consider use of other PPIs with clopidogrel
Caution when co prescribed with other antiplatelet and anticoagulant agents or NSAIDs – increased bleeding risk
What drug class is amiodarone?
A class 3 antiarrhythmic
What is the common indications for amiodarone?
Wide spectrum; effective for most arrhythmias e.g WPW, VT, AF, chronic re-entrant NCT, ectopic beats
What is the mechanism of action of amiodarone?
Block the K+ channels, preventing efflux of potassium from cardiac myocytes. Membrane takes longer to repolarise and action potential duration increases. Prolonged refractory period and APD.
What are the adverse effects of amiodarone?
Pulmonary fibrosis (SoB) Hepatic injury Increase LDL cholesterol (treat with statins) Thyroid disease. Photosensitivity Optic neuritis
What are the important drug drug interactions of amiodarone?
Reduce dose of digoxin
Monitor warfarin more closely
Why is amiodarone contraindicated in thyroid disease?
Amiodarone has a high iodine content and therefore can influence the action of the thyroid causing hyperthyroidism or hypothyroidism
What is the drug class of verapamil?
CCB
Non- dihydropyridine
Phenylalkylamines - class IV anti-arrhythmic agent
What are the common indications of verapamil?
Control ventricles during SVT Convert SVT (re-entry around the AV)
What is the mechanism of action of verapamil?
Calcium channel blocker that are more selective for myocytes than peripheral vasculature smooth muscle.
Decreases the slope of Phase 0 by decreasing inward calcium currents.
Slow conduction through the AV
Prolongs the AP and effective refractory period
Negative chronotropic and inotropic effects.
What are the adverse effects of verapamil?
Caution when partial AV block and cardiac failure present
Caution when hypotension, decreased CO, or sick sinus.
GI problems - constipation.
Bradycardia.
What are the portent drug-drug interactions of verapamil?
Beta blockers - can cause asystole
Other Antihypertensive and antiarrhythmic agents
How does the pharmadynamics of verapamil differ to other drugs in the broad class which dictates its primary therapeutic uses?
Verapamil is a calcium channel blocker, much like amlodipine. Different classes of CCB interact with different sites on the alpha1 subunit of the VOCC. They also have different selectivity for vascular smooth muscle or myocardium.
Verapamil - a non-dihydropyridine - is more selective for myocardium, having negative chronotropic and inotropic effects
Amlodipine is a dihydropyridine and is more selective for peripheral vasculature, decreasing TPR in hypertension.
What drug class is aspirin?
Cyclo-oxygenase inhibitor