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RBF: 1) Drugs > Lecture 16 - Inotropic drugs > Flashcards

Lecture 16 - Inotropic drugs Flashcards

1
Q

What is an inotrope?

A

A drug that changes the force of cardiac muscle contraction.

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2
Q

What is a positive inotrope?

A

A drug that increases the contractility of cardiac muscle. It is typically used to support cardiac function in conditions such as heart failure, cardiogenic shock, septic shock, MI and cardiomyopathy.

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3
Q

What is a negative inotrope?

A

A drug that decreases the contractility of cardiac muscle. It is used to decrease cardiac workload in conditions such as angina.

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4
Q

What happens when inotropy is increased?

A

There is an increase in calcium influx or calcium release by sarcoplasmic reticulum, this causes an increase in contraction of the cardiac muscle. There is then an increase in SV (decrease in end-systolic volume and end-diastolic volume), this also increases the ejection fraction. There is also a decrease in LV end-diastolic pressure.

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5
Q

Define shock?

A

Inadequate organ perfusion to meet the tissue’s oxygenated demand leading to organ dysfunction.

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6
Q

List the types of shock?

A
  1. Hypovolemic - dehydration and haemorrhage.
  2. Cardiogenic - heart failure (heart isn’t maintaining adequate CO).
  3. Distributive - sepsis, anaphylaxis.
  4. Obstructive - cardiac tamponade, pulmonary embolism.
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7
Q

What are the signs and symptoms of hypovolemic shock?

A
  1. Rapid weak pulse.
  2. Cool clammy skin.
  3. Rapid shallow breathing.
  4. Hypothermia.
  5. Thirst and dry mouth.
  6. Cold and mottled skin.
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8
Q

What are the signs and symptoms of cardiogenic shock?

A
  1. Distended jugular veins (increased JVP).
  2. Weak or absent pulse.
  3. Abnormal heart rhythms - often fast HR.
  4. Reduced BP.
  5. Altered mental states.
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9
Q

What are the signs and symptoms of septic shock?

A
  1. Systemic leukocyte adhestion to endothelial cells.
  2. Reduced contractility of the heart.
  3. Activation of the coagulation pathways resulting in disseminated intravascular coagulation (decreased clotting factors).
  4. Increased levels of neutrophils.
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10
Q

What are the goals of shock resuscitation?

A
  1. Restore BP - give the pt fluids and positive inotropes (increase contractility).
  2. Normalise systemic perfusion - give pt positive inotropes.
  3. Preserve organ function - renal perfusion.
  4. Treat underlying cause.
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11
Q

List positive inotropic agents?

A
  1. Digoxin.
  2. Amiodarone.
  3. Dobutamine.
  4. Dopamine.
  5. Epinephrine (adrenaline).
  6. Norepinephrine (noradrenaline).
  7. Prostaglandins.
  8. Amrinone.
  9. Milrinone.
  10. Insulin.
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12
Q

List negative inotropic agents?

A
  1. Beta blockers.
  2. Diltiazem.
  3. Verapamil.
  4. Quinidine.
  5. Procainamide.
  6. Flecainide.

N.B. some beta blockers are used in heart failure (metoprolol), even though negative inotropes may exacerbate heart failure.

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13
Q

What is a vasopressor?

A

It is a drug that raises reduced blood pressure. It is an anti-hypotensive drug that can:

  1. Increase total peripheral resistance - vasoconstrictor.
  2. Sensitise adrenoreceptors to catecholamines.
  3. Increase cardiac output.
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14
Q

List some vasopressors?

A
  1. Epinephrine.
  2. Dobutamine.
  3. DOpamine.
  4. Midodrine.
  5. Hydrocortisone.
  6. Prednisone.
  7. Digoxin.
  8. Amrinone.
  9. Metamphetamine.
  10. Caffeine.
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15
Q

Describe dobutamine?

A

It is an IV beta-1 agonist that effects beta receptors in the heart. It causes increased contractility (positive inotrope) and increased heart rate. It is metabolised by the liver.

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16
Q

What is dobutamine used for?

A
  1. Inotropic support in MI.
  2. Cardiac surgery.
  3. Cardiomyopathy.
  4. Septic shock.
  5. Cardiogenic shock.
17
Q

Why do patients not take dobutamine?

A

They do not take if they have the following:

  1. Pheochromocytoma.
  2. Arrhythmias.
  3. Ischaemic heart disease.
  4. Acute MI.
  5. Acute heart failure.
  6. Severe hypotension.
  7. Obstruction of cardiac ejection - aortic stenosis.
  8. Tachycardia.
  9. Metabolic acidosis.
  10. Hypoxia.
18
Q

What are the adverse effects of dobutamine?

A
  1. Nausea.
  2. Hypotension.
  3. Arrhythmias.
  4. Tachycardia.
  5. Palpitation.
  6. Chest pain.
  7. SOB.
  8. Headache.
  9. Fever.
  10. Eosinophilia.
19
Q

Describe milrinone?

A

It is an IV phosphodiesterase III inhibitor that stops cAMP from being broken down and you see activation of protein kinase, thus a positive inotrope and vasodilator. Basically it does the following:

  1. Vasodilation.
  2. Increased organ perfusion.
  3. Decreased TPR.
  4. Decreased BP.
  5. Increased contractility and HR.
  6. Increased SV and EF.
20
Q

What is milrinone used for?

A

Short-term treatment of severe congestive heart failure.

21
Q

Why do patients not take milrinone?

A

They do not take if they have the following:

  1. Severe stenotic or obstructive valvular disease.
  2. Severe hypovolaemia.
22
Q

What are the adverse effects of milrinone?

A
  1. Ectopic beats.
  2. Ventricular tachycardia.
  3. Supraventricular arrhythmias.
  4. Hypotension.
  5. Headache.
  6. . Thrombocytopenia.
23
Q

Describe digoxin?

A

It is a cardiac glycoside that inhibits ATPase channel and increases calcium intracellulary therefore increasing contractility. It also reduces conductivity within the AV node.

24
Q

What is digoxin used for?

A
  1. AF rate control.

2. Acute heart failure.

25
Q

Why do patients not take digoxin?

A

They do not take if they have the following:

  1. Intermittent complete heart block.
  2. 2nd degree AV block.
  3. Supraventricular arrhythmias - Wolff-Parkinson-White Syndrome.
  4. VT or VF.
  5. Myocarditis.
26
Q

What are the adverse effects of digoxin?

A
  1. Nausea.
  2. Vomiting.
  3. Disturbances.
  4. Dizziness.
  5. Abdominal pain.
  6. Arrhythmias.
  7. Conduction disturbances.
  8. Blurred or yellow vision.
  9. Rash.
27
Q

What is digoxin toxicity?

A

This is when digoxin levels are too high. It can be due to drugs that inhibit p-glycoproteins, thus digoxin cannot be excreted and broken down so there is an increase in digoxin plasma levels.

28
Q

What drugs can cause digoxin toxicity (if you’re on digoxin and take these drugs)?

A
  1. Quinidine.
  2. Amiodarone.
  3. Verapamil.
  4. Diltiazem.
  5. Erythromycin.
  6. Clyclosporin.
  7. PGP inhibitors.
29
Q

Describe adrenaline?

A

Also known as epinephrine, it can be used intravenously or intra-muscularly. It is a both an alpha and beta agonist. It can increase HR, increase contractility and depending on the adrenoreceptor vasodilate (beta-2) or vasoconstrict (alpha).

30
Q

What is adrenaline used for?

A
  1. Cardiac Pulmonary Resuscitation (CPR).
  2. Anaphylaxis.
  3. Acute asthmatic attacks to relieve bronchospasm.
31
Q

Why do patient’s not take adrenaline?

A

They should be cautious of adrenaline if they have the following:

  1. Ischaemic heart disease.
  2. Severe angina.
  3. Obstructive cardiomyopathy.
  4. Hypertension.
  5. Arrhythmias.
  6. Cor pulmonale.
  7. Diabetes mellitus.
  8. Hypokalaemia.
  9. Hypercalcaemia.
  10. Renal impairment.
32
Q

What are the adverse effects of adrenaline?

A
  1. Nausae.
  2. Vomiting.
  3. Angina.
  4. MI.
  5. Tachycardia.
  6. Cold extremities.
  7. Palpitations.
  8. Hypertension.
  9. SOB.
  10. Pulmonary oedema.
  11. Tremor.
  12. Anxiety.
  13. Confusion.
  14. Dizziness.
  15. Hypokalaemia.
  16. Metabolic acidosis.
33
Q

Describe dopamine?

A

IV catecholamine that increases HR and increases contractility - beta-1 agonist.

34
Q

What is dopamine used for?

A
  1. Cardiogenic shock in MI.
  2. Cardiac surgery.
  3. Acute exacerbation of chronic heart failure.
35
Q

Why do patients not take dopamine?

A

They do not take if they have the following:

  1. Tachyarrhythmias.
  2. Pheochromocytoma.
  3. Concurrent use of halogenated anaesthesia.
  4. Hypoxia.
  5. Hypercapnia.
  6. Acidosis.
  7. Peripheral vascular diseases.
  8. Pulmonary hypertension.
  9. Cardiac ischaemia.
36
Q

What are the adverse effects of dopamine?

A
  1. Nausea.
  2. Vomiting.
  3. Chest pain.
  4. Tachycardia.
  5. Hypotension.
  6. SOB.
  7. Headache.
  8. Vasoconstriction.
  9. Palpitations.

RBF: 1) Drugs (8 decks)

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