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Heiman.pharm.vascev7
Nitrates
Question | Answer |
---|---|
Mechanism | Stimulation of intracellular cyclic guanosine monophosphate (cGMP) production Leads to dilatation of the venous bed which decreases venous return |
Mechansim cont'd | Reduced preload results in reduced filling pressure which reduces myocardial wall tension decreasing oxygen demand Some dilatation of coronary arteries |
Kinetics | Variable first past effect Short half-life Liver metabolism Rapid clearance |
Cautions | Watch for postural hypotension Use with caution in patients with open-angle glaucoma Sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra) May cause severe hypotension |
Adverse Effects | Headache Flushing Nausea/vomiting Tachycardia Hypotension Syncope Rash Blurred vision |
Names | Nitroglycerin Isosorbide dinitrate Isordil – sublingual and oral Dilatrate SR Isosorbide mononitrate Imdur - sustained release Monoket, ISMO All should be taken on an empty stomach |
Nitrates Tolerance | Tolerance to effects develops with continuous use Need a nitrate free period of 8 – 12 hours every day Usually done overnight If angina is more at night or very early in the morning this can be switched around |