Cardiology overview pharmacology

Drug Drug Interactions

 * Cyclosporin co-administration is associated with a higher rate of myositis among statin users as a result of inhibition of CYP3A4. The exception is pravastatin in which this is not a problem.
 * Nitrates should not be given to patients who are taking Cialis or Viagra. if the patient has ingested Cialis, then you should wait 48 hours to administer nitrates. If the patient is ingested Viagra, you should wait 24 hours to administer nitrates.  Hypotension following Viagra administration can be treated with phenylephrine, IV fluids and the Trendelenburg position.  Esmolol can exacerbate the hypotension associated with Viagra.
 * Dronedarone increases the level of simvastatin fourfold
 * Amiodarone increases levels of simvastatin

Grapefruit

 * Grapefruit juice inhibits the Cyp 3A4 enzyme which reduces the breakdown of drugs. Grapefruit juice also increases the p- glycoprotein in the intestines which increases drug absorption.
 * Amiodarone
 * Nifedipine
 * Simvastatin
 * Lovastatin
 * Pravastatin
 * Sildenafil (Viagra)

Drug Side Effects and Toxicity

 * Protease inhibitors are associated with the development of myocardial infarction in patients with AIDS.
 * The chemotherapeutic agent Capecitabine has been associated with an increased risk of ACS.
 * Spironolactone is associated with an increased incidence of hyperkalemia.
 * Pioglitazone is associated with an increase in weight and peripheral edema. There actually does not appear to be an increased risk of heart failure but an increased vascular permeability. In patients with edema they should be switched to metformin.
 * Nesiritide can lead to hypertension lasting for a couple of hours.
 * Genotyping can be used to dose warfarin in such a manner to reduce hospitalization.
 * Ranolazine and diltiazem can prolong the QT interval