NursingStudyHub

CARDIOVASCULAR SYSTEM DRUGS-2

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by

Liu
in

CARDIOVASCULAR SYSTEM DRUGS-2

LVF = Left ventricular failure
U&Es = Urea and electrolytes 
GFR = Glomerular filtration rate
t½ = Half-life
VTE = Venous thromboembolism

cGMP =Cyclic guanosine monophosphate

HMG CoA =3-hydroxy-3-methylglutaryl coenzyme A

MAO = Monoamine oxidas

DVT = Deep vein thrombosis

COMT = Catechol-O-methyl transferase

PE = Pulmonary embolism

VTE = Venous thromboembolism

OCP = Oral contraceptive pil

Fibrinolytics 

EXAMPLES 
Streptokinase, alteplase, reteplase, tenecteplase

MECHANISM OF ACTION
Activation of plasminogen to form plasmin, a proteolytic enzyme that promotes the breakdown of fibrin clots into fibrin degrading products leading to clot dissolution and reperfusion.

INDICATIONS 

  • Acute MI
  • Massive pulmonary embolus (alteplase)
  • Acute ischaemic stroke (under specialist supervision by stroke physician)

CAUTIONS AND CONTRA-INDICATIONS

  • Aortic dissection.
  • Active bleeding.
  • Active peptic ulcer disease.
  • Previous haemorrhagic stroke or recent ischaemic stroke.
  • Coagulation defects.
  • Recent surgery/trauma.
  • Active intracranial neoplasm.
  • Uncontrolled hypertension (relative contraindication)

SIDE-EFFECTS

  • Bleeding (including cerebral haemorrhage).
  • Nausea and vomiting.
  • Reperfusion cardiac arrhythmias and ischaemia.
  • Cerebral and pulmonary oedema.
  • Anaphylaxis.
  • Severe hypotension

METABOLISMANDHALF-LIFE 
Variable–t½ for streptokinase is18–23min;t½ for alteplase is 4–5min. Metabolised predominantly by the liver.

MONITORING 
Monitor for signs of bleeding, anaphylaxis and intracranial haemorrhage.

DRUG INTERACTIONS

  • Risk of haemorrhage is increased with oral anticoagulants.
  • Patients on ACEIs are at an increased risk of anaphylactoid reaction when streptokinase is administered

IMPORTANT POINTS

  • Fibrinolytics are licensed for ST-elevation MI within 12h of the onset of chest pain (administered ideally within one hour).
  • Streptokinase is derived from b-haemolytic Streptococci of Lancefield group C; persistence of antibodies to streptokinase may reduce the effect of subsequent doses. It has effectively been superseded by the newer fibrinolytics(e.g.reteplase)in acute mi(where primary percutaneous coronary intervention is not available).
  • Alteplase is a recombinant tissue-type plasminogen activator.
  • Does not cause allergic reactions and can be used in patients with recent streptococcal infections or recent use of streptokinase


Flecainide 
MECHANISM OF ACTION 

  • Blocks Naþ dependent channels hence depressing phase 0 of the cardiac action potential.
  • Increased PR and QRS intervals and lengthened ventricular refractory period lead to slower conduction of electrical impulses, with the greatest effect noted on the bundle of His and Purkinje system.
  • In addition to the negative chronotropic effect, flecainide also reduces contractility.

INDICATIONS

  • Wolff–Parkinson–White syndrome.
  • AV nodal reciprocating tachycardia (AVNRT).
  • Ventricular tachyarrhythmias

CAUTIONS AND CONTRA-INDICATIONS

  • Second and third-degree AV block. SA node dysfunction. Impaired LV function.
  • Long-standing AF. History of structural heart disease e.g. previous MI

SIDE-EFFECTS