Drug Interactions of Antihypertensives (Part 13):

Drug Interactions of Organic Nitrates:

More presentations from Naina Mohamed Pakkir Maideen

© Organic nitrates  include Isosorbide dinitrate, Isosorbide mononitrate, Nitroglycerin (GTN), Erythrityl tetranitrate and Pentaerythritol tetranitrate.

©   Organic nitrates are commonly used to treat angina pectoris, myocardial infarction, and congestive heart failure.

©   Nitroglycerine may be useful to lower blood pressure in acute hypertensive emergencies resulting from a pheochromocytoma, renal artery stenosis, aortic dissection, etc. Nitrodilators may also be used during surgery to control arterial pressure within desired limits.

©   Mechanism of Action of Organic nitrates in Angina pectoris:

©   Mechanism of action of Organic nitrates in Heart Failure:

©   Organic nitrates can interact with drugs such as PDE 5 Inhibitors (Sildenafil, Tadalafil, Vardenafil, Avanafil) and Riociguat.

©   Concomitant use of Organic nitrates and PDE 5 Inhibitors such as Sildenafil, Tadalafil, Vardenafil and Avanafil is Contraindicated.

©   Coadministration of Riociguat with Organic nitrates is contraindicated due to an increased risk of hypotension.

©   If possible, concomitant use of Nitroglycerin (GTN) and Alteplase should be avoided.

©   Careful monitoring of PTT and Heparin dose adjustment is recommended, when heparin and Nitroglycerin (GTN) are coadministered.

©   The patients with hypertension should bring a list of all of the drugs they are taking including prescription drugs, over the counter (OTC) drugs, and any supplements, herbal or otherwise, during their visit to the doctor or pharmacist.

Drug Interactions of Antihypertensives (Part 12):

Drug Interactions of Arterial Vasodilators:

More presentations from Naina Mohamed Pakkir Maideen

©   Arterial Vasodilators include Hydralazine and Minoxidil.

©   Arterial Vasodilators are commonly used to treat Systemic and Pulmonary hypertension, heart failure and angina. 

©   Hydralazine can interact moderately with drugs such as Beta blockers (Propranolol, Oxprenolol, Metoprolol), Indomethacin, Ma Huang (Ephedra) and Yohimbine.

©   The risk of adverse effects (Bradycardia, Fatigue, and Bronchospasm) of Beta blockers is elevated by the concurrent use of Hydralazine and Beta blockers. Switch to a sustained release beta blocker, if concurrent therapy of Hydralazine and Beta blockers is required.

©   Concomitant use of Hydralazine and Indomethacin warrants monitoring of blood pressure.

©   Due to ephedrine content of Ma Huang, concomitant use of Ma huang is not advised in patients using antihypertensives.

©   Use of Ma huang is contraindicated in patients who are ephedrine or pseudoephedrine sensitive, and those with renal failure or pheochromocytoma.

©   Avoid concomitant use of Hydralazine or Minoxidil and yohimbine.

©   Maintenance of consistent dosing of Hydralazine is recommended with relation to meals.