Cardiac Pharmacology: Difference between revisions

''Heather Melrose, Jonas de Jong''

==Renin-Angiotensin-Aldosterone System==

The renin-angiotensin-aldosterone system (RAAS) is an important hormone-based pathway within the body that regulates fluid balance and thus systemic blood pressure. The system is activated by decreases in blood volume or pressure detected in two ways: a drop in blood pressure detected by baroreceptors (pressure sensors) located in the carotid sinus or a drop in flow rate through the kidneys, detected by the juxtaglomerular apparatus. The body responds to these stimuli to effect a restoration in blood pressure via the actions of three hormones; renin, angiotensin and aldosterone. Following the detected drop in blood pressure, the enzyme renin is released from specialised cells within the kidney. The substrate of renin is the inactive precursor of angiotensin I, angiotensinogen. Angiotensin I is then enzymatically converted by angiotensin converting enzyme (ACE) into angiotensin II, a hormone with various actions throughout the body that ultimately increase blood pressure, restoring fluid balance within the body.  

==Neural Control of the Cardiovascular System==

===Sympathetic (Adrenergic) Nervous System===

The adrenergic nervous system is a vital component of many processes throughout the body, including the cardiovascular system. Circulating catecholamines (e.g. adrenaline and noradrenaline) bind to and activate adrenergic receptors on cell membranes. Adrenergic receptors are a class of G-protein coupled receptors that elicit a variety of tissue-specific effects and exist in several subtypes.  

==Platelet/Clotting System==

Platelets (also known as thrombocytes) are small cells lacking nuclei that are responsible for haemostasis, or blood clotting. Damage or injury leading to blood loss and exposure of extracellular collagen fibres is detected, activating platelets. Once activated, platelets become adhesive, sticking to both the damaged vessel wall and each other, forming a clump of cells, or ‘clot’, helping to dam the vessel leak. They then begin to secrete cytokines that encourage invasion of fibroblasts present in the surrounding tissue which form a more permanent patch, either by creating healthy tissue, or depositing extracellular matrix to form a scar.  

|Hypertension: Class IA <cite>Esc2</cite>

|rowspan="4" valign="top"|Hypotension (2.4%), renal impairment, persistent dry cough, angioedema, rash pancreatitis, upper respiratory-tract symptoms (2-10%), gastro-intestinal symptoms (1-2%), altered liver function tests, cholestatic jaundice, hepatitis, fulminant hepatic necrosis and failure, hyperkalaemia (2%), hypoglycaemia, blood disorders including thrombocytopenia, leucopenia, neutropenia, headache (3%), dizziness (2-12%), fatigue, malaise, taste disturbance, paraesthesia, bronchospasm, fever, serositis, vasculitis, myalgia (3%), arthralgia, positive antinuclear antibody, raised erythrocyte sedimentation rate, eosinophilia, leucocytosis, and photosensitivity.

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|Heart Failure

|Captopril: 12.5mg 3 times daily

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|Prophylaxis Following MI

|Hypertension: Class IA <cite>Esc2</cite>

|rowspan="3" valign="top"|Gastro-intestinal disturbances (<3%), dizziness (14%), angina, palpitation, oedema, dyspnoea, headache (14%), malaise, urticaria, pruritus, rash;

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|Left ventricular hypertrophy

|Losartan: 12.5-150mg daily

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|Diabetic nephropathy

|Angina

|Atenolol: 100mg once/twice daily

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|Arrhythmias

|Atenolol: 50-100mg daily

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|Migraine

|Hypertension

|Nifedipine: 20-30mg once daily

|rowspan="3" valign="top"|Gastro-intestinal disturbance (2-11%); hypotension (1-5%), oedema (7-29%), vasodilatation, palpitation; headache (7-35%), dizziness (3-27%), lethargy (4-6%), asthenia (10-12%); less commonly tachycardia (<1-7%), syncope (<1%), chills, nasal congestion, dyspnoea (<3%), anxiety, sleep disturbance (<2%), vertigo (<3%), migraine, paraesthesia, tremor (1-8%), polyuria, dysuria, nocturia, erectile dysfunction (<2%), epistaxis, myalgia, joint swelling, visual disturbance (<2%), sweating (<2%), hypersensitivity reactions (<1%); rarely anorexia, gum hyperplasia, mood disturbances, hyperglycaemia, male infertility, purpura (<1%), and photosensitivity reactions (<1%); also reported dysphagia, intestinal obstruction, intestinal ulcer, bezoar formation, gynaecomastia, agranulocytosis, and anaphylaxis;

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|Angina (prophylaxis)

|Nifedipine: 5-20mg 3 times daily

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|colspan="6" bgcolor="#E6E6FA"|'''Anti-Arrhythmics'''

|Ventricular Arrhythmias

|Flecainide: 50-100mg twice daily

|Oedema, pro-arrhythmic effects (1-13%); dyspnoea; nervous-system side-effects including dizziness, asthenia, fatigue, fever; visual disturbances (13-28%); rarely pneumonitis, hallucinations, depression, confusion, amnesia, dyskinesia, convulsions, peripheral neuropathy; also reported gastro-intestinal disturbances (1-4%), anorexia, hepatic dysfunction, flushing, syncope, drowsiness, tremor, vertigo, headache, anxiety, insomnia, ataxia, paraesthesia, anaemia, leucopenia, thrombocytopenia, corneal deposits, tinnitus, increased antinuclear antibodies, hypersensitivity reactions (including rash, urticaria, and photosensitivity), increased sweating.

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|Ventricular, Arrhythmias

|Amiodarone: 200mg 2-3 times daily

|Gastro-intestinal disturbances (2-20%)), taste disturbances, hepatic disturbances (up to 50%); bradycardia; pulmonary toxicity (1-17%); tremor (9-59%), sleep disorders; hypothyroidism (5-10%), hyperthyroidism (5-10%); reversible corneal microdeposits (up to 98%); phototoxicity, persistent slate-grey skin discoloration (1-7%), injection-site reactions; less commonly onset or worsening of arrhythmia, conduction disturbances, peripheral neuropathy (1-105) and myopathy; very rarely sinus arrest, bronchospasm, ataxia (2-37%), benign intracranial hypertension, headache, vertigo, epididymo-orchitis, impotence, haemolytic or aplastic anaemia, thrombocytopenia, rash, hypersensitivity including photosensitivity (2-20%), anaphylaxis on rapid injection, hypotension (10-30%), respiratory distress syndrome, sweating, and hot flushes

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|Supra-ventricular Arrhythmias

|Acute: 0.75-1.5mg over 24 hours; Maintenance: 125-150µg daily

|rowspan="3" valign="top"|Gastro-intestinal disturbances (vomiting, diarrhoea, anorexia, abdominal pain) (25%); arrhythmias (up to 50%), AV conduction disturbances (50%); nervous system disturbances (dizziness, apathy, confusion, headache, fatigue, weakness) (25%); blurred or yellow vision; rash, eosinophilia, depression, anorexia, intestinal ischaemia and necrosis, psychosis, gynaecomastia on long-term use, and thrombocytopenia.

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|Heart Failure

|62.5-125 µg daily

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|colspan="6" bgcolor="#E6E6FA"|'''Anti-platelet Drugs'''

|Prevention of thrombotic cerebro- or cardio-vascular disease

|75mg once/day

|rowspan="2" valign="top"|Bronchospasm (10-30% in asthmatics); gastro-intestinal irritation (up to 83%), gastro-intestinal haemorrhage (occasionally major), also other haemorrhage (e.g. intracranial (0.5%), subconjunctival), chest pain (8.3%), oedema (4.5%), hypertension (4.3%).

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|Prevention of thrombotic events (esp. when warfarin not tolerated)

|75mg once/day

|rowspan="3" valign="top"|Dyspepsia (5.2%), abdominal pain (5.6%), diarrhoea (4.5%); bleeding disorders including gastro-intestinal (2.0%) and intracranial (0.4%), nausea (3.4%), vomiting, gastritis, flatulence, constipation, gastric and duodenal ulcers, headache (7.6%), epistaxis (2.9%), dizziness (6.2%), paraesthesia, leucopenia, decreased platelets (very rarely severe thrombocytopenia), eosinophilia, rash (4.2%), pruritus (3.3%), vertigo, colitis, pancreatitis, hepatitis (<1%), acute liver failure, hypertension (4.3%), chest pain (8.3%), oedema (4.1%), vasculitis, confusion, hallucinations, taste disturbance, cough (3.9%), fatigue (4.8%) stomatitis, bronchospasm, interstitial pneumonitis, pyrexia (2.2%), blood disorders including thrombocytopenic purpura (5.3%), agranulocytosis, neutropenia (0.04%) and pancytopenia and hypersensitivity-like reactions (<0.1%)including fever, glomerulonephritis, arthralgia, Stevens-Johnson syndrome, toxic epidermal necrolysis, lichen planus.

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|Acute myocardial infarction

|300mg daily initially then 75mg once/day

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|Acute coronary syndrome

|300mg daily initially then 75mg once/day

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|Prasugrel

|Prevention of thrombotic events.

|60mg bolus then 5-10mg once daily

|Haemorrhage (11.3%) (including gastro-intestinal (1.5%) and intracranial), haematoma, haematuria, hypertension (7.5%), hypotension (3.9%), headache (5.5%), back pain (5.0%), dyspnoea (4.9%), nausea (4.6%), dizziness (4.1%), cough (3.9%), fatigue (3.7%), chest pain (3.1%), arrhythmias including atrial fibrillation (2.9%) and bradycardia (2.9%), rash (2.8%), pyrexia (2.7%), oedema (2.7%), diarrhoea (2.3%), hypercholesterolaemia/hyperlipidaemia (7.5%), anaemia, rash,hypersensitivity reactions including angioedema (0.06%), thrombocytopenia (0.06%), thrombotic thrombocytopenic purpura.

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|Prevention of thrombotic events.

|180mg bolus then 90mg twice daily

|Dyspnoea (13.8%), haemorrhage, bruising; nausea (4.3%), vomiting, diarrhoea (3.7%), hypertension (3.8%), hypotension (3.2%), back pain (3.6%), abdominal pain, dyspepsia, gastritis, dizziness (4.5%), chest pain (3.7%), headache (6.5%), cough (4.9%), rash, pruritus, fatigue (3.2%),  constipation, arrhythmias including atrial fibrillation (4.2%), paraesthesia, confusion, hyperuricaemia, raised serum creatinine (7.4%), vertigo.

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|Primary hyper-cholesterolaemia, combined hyperlipidaemia

|Simvastatin: 10-20mg once daily

|rowspan="3" valign="top"|Oedema (2.7%), abdominal pain (5.9%), nausea (5.4%), atrial fibrillation (5.7%), constipation (2.2%), gastritis (4.9%), diabetes mellitus (4.2%), myalgia (3.7%), headache (2.5%), insomnia (4.0%), vertigo (4.5%), bronchitis (6.6%), sinusitis (2.3%), eczema (4.5%), urinary tract infection (3.2%)

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|Familial hyper-cholesterolaemia

|Simvastatin: 40mg once daily

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|Prevention of cardiovascular events

|20-40mg once daily

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|rowspan="2"|Fibrates

|Hyperlipidaemias of types IIa, IIb, III, IV and V  

|Gemfibrozil: 0.9-1.2mg daily

|Gastro-intestinal disturbances including dyspepsia (19.6%), nausea (4%), abdominal pain (9.8%), diarrhoea (7.2%), vomiting (1.2%); headache (1.2%), fatigue (3.8%), vertigo (1.5%), eczema, rash (1.7%), atrial fibrillation (0.7%), pancreatitis, appendicitis, disturbances in liver function including hepatitis and cholestatic jaundice, dizziness, paraesthesia, sexual dysfunction, thrombocytopenia, anaemia, leucopenia, eosinophilia, bone-marrow suppression, myalgia, myopathy, myasthenia, myositis accompanied by increase in creatine kinase, blurred vision, exfoliative dermatitis, alopecia, and photosensitivity

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|Primary and familial hyper-cholesterolaemia

|10mg once daily

|Gastro-intestinal disturbance including diarrhoea (4.1%) and abdominal pain (3.0%); headache, fatigue (2.4%); myalgia, arthralgia (3.0%), sinusitis (3.6%), pharyngitis (2.3%), viral infection (2.2%), coughing (2.3%), hypersensitivity reactions including rash, angioedema, and anaphylaxis, hepatitis,pancreatitis, cholelithiasis, cholecystitis, thrombocytopenia, raised creatine kinase, myopathy, and rhabdomyolysis

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==References==

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