Block Five Flashcards
(222 cards)
1
Q
What do cardiac stimulants do?
A
- Improve heart function
- Stimulate heart in heart failure or shock
2
Q
What are antihypertensive drugs?
A
- Reduces the workload of the heart
- Reduces the damage that high blood causes
3
Q
What drugs fit into the category of antihypertensives?
A
- Adrenergic receptor antagonists (blockers)
- Calcium channel blockers
- Peripheral vasodilators
- ACE inhibitors
- Angiotensin II receptor blockers (ARBs)
- Diuretics
4
Q
What are lipid lowering drugs?
A
- Drugs that reduce possible vascular occlusions
- Drugs that reduce intravascular clot formation
5
Q
What is pre-eclampsia?
A
The development of hypertension with proteinuria or oedema or both, induced by pregnancy after the 20th week of gestation
6
Q
What is eclampsia?
A
Convulsion not caused by any neurological disease in a woman whose condition also meets the requirements for pre-eclampsia
7
Q
What is a key component of pre-eclampsia and eclampsia?
A
Hypertension in pregnancy
8
Q
What can hypertension cause in pregnant woman?
A
- Cerebral haemorrhage
- Heart failure
9
Q
What are common cardiac drugs?
A
- Adrenaline
- Dopamine
- Dobutamine
- Digoxin
- Isosorbide mononitrate
- Glyceryl trinitrate
- Hydralazine
10
Q
What is an inotropic effect?
A
Increase or decrease in the contractile force of the heart
11
Q
What is a chronotropic effect?
A
Increase or decrease in heart rate
12
Q
What are the two groups of cardiac stimulants?
A
- Sympathomimetics
- Cardiac glycosides
13
Q
What are adrenergic agonists drug?
A
Drugs can activate receptors in four basic ways, either:
- Direct binding
- Promotion of noradrenaline release
- Inhibition of noradrenaline re-uptake
- Inhibition of noradrenaline inactivation
14
Q
What is the mode of action of direct binding adrenergic agonists drugs?
A
Direct interaction with receptors, mimicking the
actions of neurotransmitters
15
Q
What are examples of adrenergic agonists drugs?
A
- Adrenaline
- Dopamine
16
Q
What is the mode of action of promotion of noradrenaline release adrenergic agonists drugs?
A
Drugs activate adrenergic receptors by acting on terminals of sympathetic nerves to cause noradrenaline release
17
Q
What is the mode of action of inhibition of noradrenaline re-uptake adrenergic agonists drugs?
A
Blocking re-uptake drugs can cause noradrenaline to accumulate within the synaptic gap and can thereby increase receptor activation
18
Q
What is the mode of action of inhibition of noradrenaline inactivation adrenergic agonists drugs?
A
Some noradrenaline terminals are inactivated by monoamine oxidase (MAO). Drugs that inhibit MAO can increase the amount of NA available for release
19
Q
What is adrenaline used for in the cardiac system?
A
- Circulatory shock
- Hypotension
- Cardiac arrest
20
Q
What is the mode of action of adrenaline in the cardiac system?
A
Acts mainly on beta-1 receptors in the heart muscle giving an increased rate of contraction and increased force of contraction, increasing myocardial contractility
21
Q
What are adverse effects of adrenaline?
A
- Nausea
- Vomiting
- Tremors
- Agitation
- Dizziness
- Hypertension
- Constipation
- Tachycardia
22
Q
How is adrenaline administered?
A
- IV
- IM
23
Q
What is dopamine used for in the cardiac system?
A
- Circulatory shock
- Low, moderate and high doses will stimulate different adrenergic receptors and result in different effects
24
Q
What is the mode of action of dopamine?
A
- Stimulate beta1-receptors on the heart
- At high doses, alpha receptors associated with systemic blood vessel
25
How is dopamine administered?
IV
26
What does dobutamine do?
- Acts directly on heart muscle to increase the force of myocardial contraction
- Produces little increase in heart rate and peripheral vascular resistance
27
What is the first choice of drug for circulatory shock and why?
- Dobutamine
| - Causes less vasoconstriction in the peripheries and if the IV line tissues it is less likely to cause tissue damage
28
What are common adverse effects of dobutamine?
- Increase in heart rate
- Increase in ventricular ectopic beats
- Tolerance
- Nausea/vomiting
29
What is an example of cardiac glycosides?
Digoxin
30
What is digoxin used for?
- Congestive heart failure
| - Atrial fibrillation
31
What is the mode of action of digoxin?
- Increased vagal activity slows conduction of the atrioventricular node, slowing heart rate. This increases time is available for the ventricles to fill, improving cardiac output
- The increase in force of contraction is attributed to - Digoxin’s inhibits Na/K pump, increasing Na+ concentration and causing slower Ca++ outflow via the Na+/Ca++ exchanger and increasing Ca++ in the cell. The extra Ca++ causes greater strength of contraction of cardiac muscle cells
32
What are characteristics of digoxin?
- Option in elderly patients with atrial fibrillation
- Does not cause hypotension
- Does not have negative inotropic effects
- Narrow therapeutic index
- Half life of 40 hours
33
What is an antidote for digoxin and how do they work?
- Digibind or DigiFab
| - Bind the digoxin molecules, preventing them from interacting at the site of action
34
What is an adverse effect of digoxin?
- Arrhythmias
- GI disturbances
- CNS effects (disorientation, visual disturbances, confusion, hallucinations)
35
What are toxic effects of digoxin?
- Nausea
- Vomiting
- Anorexia
- Disorientation
- Visual disturbances
36
How does potassium interact with digoxin?
- High levels reduce the effects of digoxin
| - Low levels enhance the effect of digoxin
37
What are care considerations with digoxin?
1) Monitor potassium levels.
2) Monitor for manifestations of digoxin toxicity
3) Monitor serum digoxin levels.
4) Check apical pulse and if less than 60 beats/min check with doctor prior to administration
5) Digoxin is eliminated by renal excretion, check renal function
38
What are therapeutic indications for peripheral dilators?
- Angina
- CHF
- Hypertension
- Peripheral vascular disease
- Production of controlled hypotension during surgery
39
What do peripheral dilators do?
- Dilate veins
| - Reduce workload on the heart
40
What are examples of nitrates?
- Glyceryl trinitrate (variety of different routes)
| - Isosorbide mononitrate (oral)
41
What are adverse effect of nitrates?
- Dizziness
- Headaches
- Facial flushing
- Hypotension
- Tachycardia
42
What do nitrates do?
Cause vasodilation
43
What is the mode of action of nitrates?
1) Nitrates are converted into nitric oxide (NO) in the vascular muscle
2) Nitric oxide increases the intracellular levels of cGMP
3) cGMP causes decreased calcium ion levels in the muscle cells
4) Blood vessels relax and dilate
5) Preload is reduced
44
What are characteristics of nitrates?
- Lipid soluble
- Rapidly absorbed
- GTN has 90% loss by first pass metabolism therefore given as paste sublingually or on skin
- Other nitrates administered orally
45
What are arteriole vasodilators?
- Reduce the peripheral resistance by relaxing vascular smooth muscles
- Induce arteriole dilation, thereby reducing after load
46
What is an example of an arteriole vasodilator?
Hydralazine
47
What are adverse effects of arteriole vasodilators?
- Hypotension
- Headaches
- Peripheral oedema
- Allergic rash
48
What can prolonged use of arteriolar and venous dilators cause?
Increased blood volume due to bodies attempt to restore blood pressure to pretreatment levels
49
How does increased blood volume occur from prolonged arteriolar and venous dilators use?
- Decreased arterial pressure decreases renal blood flow, resulting in less urine production
- Reduced blood pressure which triggers the renin angiotensin aldosterone pathway
50
What is the ultimate foal in treating hypertension?
Reduce cardiovascular and renal morbidity and mortality
51
What are systems that help regulate blood pressure?
- Sympathetic baroreceptor reflex
- Renin-angiotensin-aldosterone pathway
- Renal regulation
52
What are common cardiac drugs?
```
Alpha-blockers:
- Doxazosin
- Terazosin
Beta-adrenoceptor blocking drugs:
- Metoprolol
- Atenolol
- Carvedilol
- Labetalol
Calcium channel blockers:
- Amlodipine
- Felodipine
```
53
What are examples of alpha blockers?
- Doxazosin
| - Terazosin
54
What do alpha blockers do?
- Control hypertension
- Control peripheral vascular disease
- Control urinary retention
55
What are adverse effects of alpha blockers?
- Postural hypotension
- Nasal congestion
- Fatigue
- Inhibition of ejaculation
56
What are examples of selective beta blockers?
- Metoprolol
| - Atenolol
57
What are examples of non-selective blockers?
- Carvedilol
| - Labetalol
58
What are the four useful actions that beta-blockers have in hypertension?
- Block beta-adrenergic receptors in the heart - decrease heart rate and contractility therefore decreases cardiac output and BP
- Suppress reflex tachycardia caused by vasodilators
- Reduce the release of renin by the kidneys, hence less fluid retention
- Long term use reduces peripheral vascular resistance
59
What are adverse effects of beta-blockers?
- Dizziness
- Tiredness
- Coldness in body extremities
- Decreased atrioventricular conduction
60
What are beta blockers used for?
- Hypertension
- Angina
- Cardiac arrhythmias
- CHF
- Migraine prophylaxis
- Cardiac disease
61
What occurs if beta blockers are given with other anti-arrhythmia drugs?
Drug interactions
62
What can discontinuation of beta blockers cause?
- Rebound hypertension
- Angina
- Arrhythmias
- Myocardial infarction
63
What is the mode of action of non-selective blockers?
Blocks alpha1 and beta-receptors
64
What is the mode of action of alpha 2 receptor agonists?
- Stimulates the alpha-2 receptors in the vasomotor centre of the medulla oblongata which inhibits noradrenaline release
- Diminished sympathetic response, lowered cardiac output and drop in blood pressure
65
What are examples of calcium channel blockers?
- Amlodipine
| - Felodipine
66
What are adverse effects of calcium channel blockers?
- Hypotension
- Skin rash
- Flushing of the skin
- Bradycardia
67
What causes drug interaction for calcium channel blockers?
- Some beta blockers
- Diltiazem
- Digoxin
- Inhibitors of CYP3A4 (grapefruit juice, erythromycin)
68
What do calcium channel blockers do?
Decreases force of myocardial contraction
69
What is the mode of action of calcium channel blockers?
Blocks calcium channel and stops calcium entering into the vascular and cardiac cells
70
What is nimodipine?
Calcium antagonist that is relatively selective for cerebral blood vessels
71
What are characteristics of nimodipine?
- Will increase cerebral blood flow particularly to damaged areas of the brain
- Highly lipid soluble
- Can cross BBB easily
- Potentially very toxic
72
What are overdoses of calcium channel blockers treated with?
Activated charcoal and whole bowel irrigation
73
What are commonly used drugs int treating hypertension and CHF?
```
ACE inhibitors:
- Cilazapril
- Quinapril
Angiotensin-II receptor antagonists (ARBs):
- Losartan
- Candesartan
Diuretics:
- Bendroflumethiazide (bendrofluazide)
- Hydrochlorothiazide
- Furosemide (or frusemide)
- Spironolactone
```
74
What are benefits of ACE inhibitor therapy?
- Can prevent progression to heart failure in patients with asymptomatic left ventricle dysfunction
- Extremely effective at improving survival and symptoms in severe to mild-to-moderate CHF
75
What is the first line drug of choice for treating pulmonary and peripheral oedema?
Diuretics
76
What is the pharmacological treatment of CHF?
A combination of diuretic and ACE inhibitor
77
What are examples of angiotensin converting enzyme inhibitors (ACE Inhibitors)?
- Cilazapril
| - Quinapril
78
What is the mode of action of ACE inhibitors?
- Inhibits the enzyme angiotensin converting enzyme causing less angiotensin II to be made
- Small arteries and veins will relax and dilate causing lower blood pressure
- Causes improved survival rates for patients
79
What are drug interactions between ACE inhibitors?
- Diuretics
- Lithium
- NSAIDs
80
What are adverse effects of ACE inhibitors?
- Hypotension
- Unproductive cough
- Taste disturbances
- Headache
- GI upset
- Hyponatremia
- Hyperkalaemia
81
What are examples of Angiotensin II Receptor Inhibitors (ARBs)?
- Losartan
| - Candesartan
82
What is the clinical application of Angiotensin II Receptor Inhibitors (ARBs)?
- Essential hypertension
| - Heart failure
83
What is the mode of action of Angiotensin II Receptor Inhibitors (ARBs)?
1) Selectively blocks the Angiotensin II subtype 1 (AT1) receptor which stimulate further renin release, increasing circulation of Angiotensin II
2) Angiotensin II cannot bind to AT1 receptors as they are blocked by the Angiotensin II inhibitors meaning angiotensin II is free to bind to the angiotensin II subtype 2 receptors (AT2)
3) This decreases systemic vascular resistance
84
What are adverse effects of Angiotensin II Receptor Inhibitors (ARBs)?
- Headaches
- Hypotension
- Dizziness
- GI disturbances
85
What are different categories of diuretics?
- Thiazides
- Loop Diuretics
- Potassium Sparing
86
What are examples of thiazides diuretics?
- Bendroflumethiazide
| - Hydrochlorothiazide
87
What is the mode of action of thiazides diuretics?
Act on distal convoluted tubule of nephron and decreases sodium reabsorption, increases concentration of fluid entering collecting ducts and induces diuresis
88
What are adverse effects of thiazides diuretics?
- Hyponatremia
- Hypokalaemia
- Hyperglycaemia
89
What is the effect of thiazides diuretics?
Results in more concentrated fluid entering the collecting ducts and therefore slows down water reabsorption
- Results in diuresis
90
What can use of lithium and thiazide cause?
Low sodium levels can lead to lithium toxicity
91
What is an example of a loop diuretic?
Furosemide
92
Where do loop diuretics work?
Loop of Henle
93
What is the mode of action of loop diuretics?
Inhibit reabsorption of sodium and chloride ions from Loop of Henle into interstitial fluid
94
What are common adverse effects of loop diuretics?
- Hyponatraemia
- Hypokalaemia
- Dizziness
- Headaches
- Dehydration
95
What is a specific adverse effect of loop diuretics?
Deafness
96
What can occur if loop diuretics are taken with digoxin?
The low potassium levels can enhance digoxin activity and lead to digoxin toxicity
97
What can occur if loop diuretics are taken with lithium?
Low sodium levels can lead to lithium toxicity
98
What is an example of potassium sparing diuretics?
Spironolactone
99
What do potassium sparing diuretics do?
Prevent potassium loss from the use of other diuretics therefore often given concurrently with the other diuretic
100
What are the two types of potassium sparing diuretics?
- Spironolactone (aldosterone antagonist)
| - Amiloride
101
What does spironolactone do?
Inhibits the action of aldosterone in the distal tubule leading to sodium loss and potassium being retained
102
What does amiloride do?
Acts directly on potassium/sodium interchange in the distal tubule causing sodium loss and potassium retention
103
What are characteristics of osmotic diuretics?
- Used in emergency situations
- Used to treat states of oedematous and CHF
- Administered via IV
104
What is the mode of action of osmotic diuretics?
Expand extracellular fluid and plasma volume which increases blood flow to kidney, increases osmolarity of blood and renal filtrate and promotes diuresis
105
What are common adverse effects of osmotic diuretics?
- Electrolyte imbalance
- Dehydration
- Hypovolaemia
106
What are examples of anticoagulants?
- Heparin and low molecular weight heparins
- Warfarin
- Dabigatran
107
What are examples of antiplatelets?
- Aspirin
| - Clopidogrel
108
What are examples of thrombolytics?
- Streptokinase
- Tissue plasminogen activator (tPA)
- Tenecteplase
109
What does injury to the wall of a blood vessel trigger?
- Vasoconstriction
- Platelet aggregation
- Conversion of fibrinogen into a fibrin clot
110
What are characteristics of heparin?
- Occurs naturally in the body
- IV (onset in minutes( or subcutaneous (onset 1-2 hours), not orally or IM
- Safe in pregnancy, as doesn’t cross the placenta
111
What is heparin used for?
- Prophylaxis
- Treatment of clotting disorders
- Coronary occlusion
- Cerebral thrombosis
112
What is a key concern when using heparin?
Haemorrhaging - important to complete regular monitoring and blood tests
113
What to give if there is an overdose of heparin?
Protamine sulphate solution (IV pushed over 1-3 minutes)
114
What are characteristics of dalteparin (fragmin)?
- Modified low molecular weight heparin
- Long half-life
- Can be administered once or twice daily
- Less likely to cause thrombocytopenia
- More expensive
115
What are examples of warfarin?
- Marevan
| - Coumadin
116
When is the onset of warfarin and how long does it last?
- 36 to 72 hours
| - 4 to 5 days
117
How does warfarin work?
- Interferes with the use of vitamin K for prothrombin production
- Inhibits epoxide reductase which oxidises Vitamin K for reuse
118
What is a key concern of warfarin?
Overdose resulting in haemorrhage - regular monitoring is required (blood tests and prothrombin time, PTT)
119
What is the antidote of warfarin?
Vitamin K (Konakion)
120
What are possible drug interactions of warfarin?
- Warfarin is displaced from its protein binding site by other drugs e.g. salicylates, clofibrate, sulphonylureas (this will increases the anticoagulant effect)
- Other drugs increase the liver metabolising enzymes and increase the metabolism of Warfarin e.g. alcohol, anticonvulsants (this will decrease the anticoagulant effect)
121
What is the mode of action of aspirin?
- Specifically blocks the production of thromboxane
| - This prevents vasoconstriction or further platelet aggregation
122
What effects are aspirin used for?
- Analgesic effects
| - Anti-inflammatory effects
123
What do thrombolytics do?
Promote conversion of plasminogen into plasmin which can then dissolve existing clots
124
What are characteristics of streptokinase?
- Enzyme prepared from beta-haemolytic streptococci therefore can cause allergic reactions including anaphylaxis
- Because of the antigenic action, this drug is usually only used once
- IV
125
What are characteristics of tissue plasminogen activator (tPA)?
- Produced by recombinant DNA technology therefore has no risk of anaphylaxis
- Works like natural human plasminogen activator
- IV
126
What are key problems with all thrombolytic agents?
- Haemorrhage
- Internal bleeding of the gastrointestinal tract
- Urogenital tract
- Intracranial
- Retroperitoneal
- Bleeding at wound or surgery sites
127
What are common lipid lowering drugs?
- Atorvastatin
- Simvastatin
- Bezafibrate
- Ezemtimbe
128
What are the three types of lipid lowering drugs?
- HMG-CoA Reductase Inhibitors (Statins)
- Fibrates
- Cholesterol absorption inhibitors
129
What are examples of HMG-CoA Reductase Inhibitors (Statins)?
- Simvastatin
| - Atorvastatin
130
What are HMG-CoA Reductase Inhibitors (Statins) the first line drug for treatment of?
Hypercholesterolaemia
131
What is the mode of action of HMG-CoA Reductase Inhibitors (Statins)?
Inhibits the enzyme HMG-CoA reductase which leads to a decreased production of cholesterol and hence decreased levels of blood cholesterol. This causes a reduction in liver production of cholesterol leading to an increase in liver LDL receptors, which aids in removing LDL from the blood
132
What do HMG-CoA Reductase Inhibitors (Statins) do?
Decrease levels of LDL and cholesterol in the blood by inhibiting the enzyme HMG-CoA reductase
133
What are characteristics of HMG-CoA Reductase Inhibitors (Statins)?
- Administered orally
- Extensive first pass effect - low bioavailability
- Minimal amounts of drug enter systemic circulation
- Important to have periodic liver function tests
- Excreted via faeces
134
What are common adverse effects of HMG-CoA Reductase Inhibitors (Statins)?
- Fatigue
- Muscle or joint pain
- Heart burn
- Headache
135
What are serious adverse effects of HMG-CoA Reductase Inhibitors (Statins)?
- Rhabdomyolysis
- Skeletal muscle breakdown
- If other lipid lowering drugs are used in combination with statins there is an increased risk of development of myalgia
136
What are possible interaction that HMG-CoA Reductase Inhibitors (Statins) can have?
Drugs that inhibit the drug metabolizing liver enzyme CYP3A4, such as:
- Macrolide antibiotics
- Azole antifungals
- HIV protease inhibitors
- The fibrate gemfibrozil
- Diltiazem
- Nicotinic acid
- Grapefruit juice
137
What do fibrates do?
Reduce high blood TG levels
138
What is an example of a fibrate?
Bezafibrate
139
What is the mode of action of fibrates?
To increase breakdown of tissue triglycerides (lipolysis) which enhances VLDL clearance, produces a decline in LDL levels, and increase in HDL levels
140
What are common adverse effects of fibrates?
- Abdominal pain
- Diarrhoea
- Muscle pain
- Potential of gallstones (need regular liver function and FBC tests)
- In combination with statin drugs, fibrates cause an increased risk of rhabdomyolysis
141
What is an example of a cholesterol absorption inhibitor?
Ezetimbe
142
What are cholesterol absorption inhibitors (e.g. ezetimbe) used for treating?
Hypercholesterolaemia
143
What is the mode of action of ezetimbe?
Inhibits the absorption of dietary cholesterol in small intestine and bile acids leading to decreased TG, LDL and total cholesterol blood levels, probably by binding to a transport protein
144
What are characteristics of ezetimbe?
- Administered once daily
- Half life is 22 hours
- Excreted in faeces and urine
145
What are common effects of ezetimbe?
- Abdominal pain
- Diarrhoea
- Headache
146
What is a inotropic effect?
Where there is a change in the contractile force in the heart (increase is positive effect, decrease is negative effect)
147
What is a chronotropic effect?
Where there is a change in the heart rate (increase is positive effect, decrease is negative effect)
148
What is a dromotropic effect?
Where there is a change in the conduction speed of electrical impulses in the heart (increase is positive effect, decrease is negative effect)
149
What are examples of sympathomimetics?
- Adrenaline
- Dopamine
- Dobutamine
150
What heart failure is associated with systemic congestion?
Right sided heart failure
151
What heart failure is associated with pulmonary congestion?
Left sided heart failure
152
What receptors do sympathomimetics bind to?
Adrenergic receptors
153
What is the mode of action of sympathomimetics?
CAMP improved so calcium increases, coupling of actin with myosin producing positive inotropic effect
154
What is the mode of action of adrenaline?
Acts on beta1-receptors in heart for positive inotropic and chronotropic effect
155
What are common adverse effects of dopamine?
- Increase in heart rate
- Vasoconstriction
- Hypotension tolerance
- Nausea/vomiting
156
What does dopamine do?
Produces positive inotropic effects on the heart, reducing its workload and maintains renal blood flow
157
What is the mode of action of dobutamine?
Has positive inotropic effect by stimulating the beta1-receptors
158
What are characteristics of dobutamine?
- Onset of action 5 minutes
- Short half life
- Patients should be well hydrated (underlying problem for hypotension treated)
159
If the therapeutic effects of digoxin are required more quickly what would be the dosing regime?
Bolus administered IV close to the recommended dose, with smaller maintenance doses
160
What may indicate digoxin toxicity?
- Loss of appetite
- Nausea and vomiting
- Abdominal distress
161
What drug interaction can occur between digoxin and loop diuretics, corticosteroids, and lithium?
Hypokalaemia
162
What drug interaction can occur between digoxin and calcium channel blockers, and ACE inhibitors?
Can cause increase or no change in digoxin levels
163
What drug interaction can occur between digoxin and macrolides, antidiarrhoeals, prazosin, and spironolactone?
Can increase activity of Digoxin
164
What drug interaction can occur between digoxin and antacids, and bulk-laxatives?
Can reduce activity of Digoxin
165
What are the actions of peripheral vasodilators of upon veins and arterioles?
- Veins: Reduce preload; so decrease cardiac output and tissue perfusion
- Arterioles: Reduce cardiac afterload; so decrease cardiac workload and increase cardiac output and tissue perfusion
166
What peripheral vasodilator act on the veins?
Nitrates
167
What peripheral vasodilators act on the arterioles?
- Hydralazine
| - Nitroprusside
168
What are characteristics of morphine?
- Is a venodilator
- Useful in pulmonary oedema due to reducing pulmonary hypertension
- Drug of choice for pain relief during MI (decreases BP, therefore workload on the heart)
169
What are the hypertensive ABCDs?
- A is for ACE inhibitors
- B is for b-blockers
- C is for CCBs and Combined action drugs
- D is for Diuretics
170
What is the mode of action of alpha blockers?
Block the alpha1-receptor sites and reduces
| sympathetic nervous system response
171
How are alpha blockers administered?
Orally
172
What is the mode of action of beta blockers?
Block beta1 receptors in the heart muscle therefore decreases cardiac output and BP decreases
173
How are bet blockers administered?
Orally
174
What are non-selective beta blockers used for?
Pregnancy induced hypertension
175
How are non-selective beta blockers administered?
Orally or IV
176
What is the mode of action of selective beta blockers?
Block beta1-receptors which predominate in the heart
177
What are the inotropic and chronotropic effects of beta blockers?
- Negative inotropic
| - Negative chronotropic
178
When are beta blockers contraindicated?
- COPD, asthma
- Bradycardia
- Cardiogenic or hypovolaemic shock
- Severe hypotension
- Should be avoided in diabetes (especially nonselective adrenergic blockers)
179
What are examples of alpha 2 agonists?
- Methyldopa
| - Clonidine
180
What are clinical indications of calcium channel blockers?
- Angina
| - Hypertension
181
What are the inotropic and chronotropic effects of calcium channel blockers?
- Negative inotropice effect
| - Negative chronotropic effect
182
How to treat nimodipine overdose?
Treat with activated charcoal and whole bowel irrigation
183
What are clinical applications for angiotensin converting enzyme inhibitors (ACE Inhibitors)?
Hypertension
184
How are angiotensin converting enzyme inhibitors (ACE Inhibitors) administered?
Orally
185
What is a prodrug?
- Administered in an inactive (or significantly less active) form
- Once administered, the prodrug is metabolised into an active metabolite
186
Are angiotensin converting enzyme inhibitors (ACE Inhibitors) prodrugs?
Yes
187
What are people given for essential hypertension or heart failure of ACE inhibitors are contraindicated or not tolerated?
Angiotensin II receptor inhibitors (ARBs)
188
What are characteristics of Angiotensin II receptor inhibitors (ARBs)?
- Generally well tolerated
- No unproductive cough
- Reduced risk of hyperkalaemia
- Maximum effect seen 4-6 weeks
189
What do diuretics do?
- Reduce circulating fluid
- Reduce blood pressure and oedema by increasing urine production
- All diuretics enhance water and sodium excretion
- Affect other salts depends on the mechanism of action
190
What is the clinical application of thiazide diuretics?
Drug of choice for management of hypertension (mild to moderate)
191
What are clinical applications of loop diuretics?
- States of oedema
| - CHF
192
What cautions needs to occur with loop diuretics?
Monitoring and perhaps K+ supplement (slow K) is needed with frusemide since K+ may be lost in excessive amounts
193
What is the clinical application of potassium sparing diuretics?
Used mainly in the prevention of potassium loss from the use of other diuretics
194
What is an example of an osmotic diuretic?
Mannitol
195
What are clinical applications of osmotic diuretics?
- States of oedematous (e.g. glaucoma, elevation of intracranial pressure)
- CHF
- Emergency situations
196
How do blood clots occur?
1) Injury to the vessel wall due to turbulent blood flow, atherosclerosis or external trauma
2) Breakdown of the vessel wall which leads to exposure of the collagen fibres forming the blood vessel
3) This attracts the fragments called platelets to adhere to the vessel wall
4) Soon there are a larger number of platelets clumping together and forming a plug to stop the blood flow out of the vessel
5) In this process some of the platelets rupture and release some molecules such as ADP, Serotonin and Thromboxane
6) These molecules cause further aggregation of the platelets, vasoconstriction and initiation of the clotting cascade
197
What is the process of fibrin formation/common clotting pathway?
1) Prothrombin (factor II) converted into Thrombin ( factor IIa) via Factor Xa
2) Fibrinogen converted into Fibrin monomers (soluble)
3) Fibrin monomers (soluble) converted into fibrin polymers (insoluble) via Factor XIIa
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What is the intrinsic pathway of plasma clotting factors?
Blood vessel injury (endothelial damage with exposed collagen) triggers:
1) XII converted into XIIa
2) XIIa converts XI into XIa
3) XIa converts IX into IXa which joins the final clotting pathway
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What is the extrinsic pathway of tissue clotting factors?
Tissue injury triggers:
| 1) Thromboplastin to convert VII into VIIa which joins the final clotting pathway
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What is the mode of action of anti-coagulants?
- Different drugs have different sites/modes of action – but same overall effect
- Shared common final pathway
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What are clinical used of anti-coagulants?
- Angioplasty done to enlarge the lumen of a partially or completely blocked coronary artery may cause some damage to the blood vessel and trigger clotting
- Blood embolus post surgery
- Thrombi due to venous stasis
- Atrial fibrillation
- Use with IV cannula, renal dialysis
- In pregnancy or with third generation OC pills
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What is mode of action of heparin?
Acts by augmenting the function Antithrombin III, a natural inhibitor of coagulation
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What are adverse effects of heparin?
- Major adverse effect is haemorrhage
| - Common adverse effect hypersensitivity and thrombocytopenia
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What are characteristics of warfarin?
- For long term anticoagulant therapy
- Oral administration
- Onset of action (12-24 hours)
- Duration of action (3-5days)
- Narrow therapeutic index drug
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What do you monitor when using warfarin?
PT- INR (Prothrombin Time and International Normalized Ratio)
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What are special precautions when using aspirin?
- GI ulcers
- Renal impairment
- Severe liver disease
- Asthma
- Late pregnancy
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What is dual anti-platelet therapy?
- Combining aspirin and another anti-platelet drug like clopidogrel
- Now frequently used for acute coronary heart disease
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What is aspirin used adjacent with?
Used adjunct with thrombolytic therapy post MI and unstable Angina
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What are adverse effects of streptokinase?
- Antigenic due to bacterial origin
| - Severe bleeding episodes
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What are absolute contraindications of thrombolytic treatment?
- Ischaemic stroke less than 6 months
- Major surgery or trauma less then 2 weeks
- Active bleeding (excludes menses)
- Recent internal bleeding less than 6 weeks
- Neurosurgery less than 6 months
- Intracranial haemorrhage
- Significant facial trauma less then 3 months
- Cancer in brain or spinal chord
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What are relative contraindications of thrombolytic treatment?
- TIA less then 6 months
- Traumatic CPR less then 2 weeks
- Non crompressible vascular puncture
- Pregnancy
- Active peptic ulcer
- Current use of anticoagulants (INR must be less then 2)
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What needs to be monitored for thrombolytic treatment?
- Signs of bleeding
- Bleeding time
- Platelet count
- Prothrombin time PT reported as INR - used for Warfarin
- Goal 1.5-2.5 x control value or INR 2-3.5
- Partial prothrombin time (PPT) used for heparin
- Fibrinogen, fibrinogen degradation products
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What are bad lipoproteins?
- VLDL
- IDL
- DLD
- Chylomicron
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What are good lipoproteins?
HDL
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What is atherosclerosis?
- Accumulation of cholesterol in the vascular wall - atherosclerotic plaque
- Causative of coronary artery disease (angina, myocardial infarction and heart failure)
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What is dyslipidaemia?
- A metabolic disorder
- Raised levels of lipids and lipoproteins in blood
- Classed as either primary (genetically determined) or secondary (caused by diabetes, obesity, excess alcohol, drug treatment)
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What is treatment for dyslipidaemia?
Lipid-lowering drugs & diet modifications
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What is HMG-CoA reductase?
A rate-controlling enzyme of the mevalonate pathway that produces cholesterol and other isoprenoids
219
What is recommended before statin use?
Lifestyle modification - cholesterol-lowering diet and exercise
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What are statins used for?
Cardiovascular disease (management and prevention)
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What is rhabdomyolysis?
Destruction of muscle tissue that leads to renal failure
222
What are drug interactions between fibrates?
- Cholesterol-lowering medications
- Some diabetes medications (hypoglycemia)
- Blood thinners (bleeding problems)
- Statins (Rhabdomyolysis)
