Mechanisms
Losartan works by blocking the effects of angiotensin II by preventing it from binding to the angiotensin I receptor while hydrochlorothiazide works by decreasing the ability of the kidneys to absorb electrolytes. The effects of hydrochlorothiazide indirectly lower the levels of serum potassium. However, with coadministration of losartan which is an angiotensin II receptor antagonist, the low levels of potassium are reversed. Brand names
The losartan/hydrochlorothiazide combination preparation is marketed by Merck under the brand name Hyzaar and by Xeno Pharmaceuticals under the name Anzaplus. Merck, Sharp & Dohme market it as Ocsaar Plus in Israel. It is marketed as Cozaar comp in Sweden and South Africa. References
External links
"Hydrochlorothiazide mixture with Losartan". Drug Information Portal. U.S. National Library of Medicine.
In medicine, hepatopulmonary syndrome is a syndrome of shortness of breath and hypoxemia (low oxygen levels in the blood of the arteries) caused by vasodilation (broadening of the blood vessels) in the lungs of patients with liver disease. Dyspnea and hypoxemia are worse in the upright position (which is called platypnea and orthodeoxia, respectively). Pathophysiology
The hepatopulmonary syndrome results from the formation of microscopic intrapulmonary arteriovenous dilatations in patients with both chronic and far less common, acute liver failure. The mechanism is unknown but is thought to be due to increased liver production or decreased liver clearance of vasodilators, possibly involving nitric oxide.The dilation of these blood vessels causes overperfusion relative to ventilation, leading to ventilation-perfusion mismatch and hypoxemia. There is an increased gradient between the partial pressure of oxygen in the alveoli of the lung and adjacent arteries (alveolar-arterial [A-a] gradient) while breathing room air. Patients with HPS have platypnea-orthodeoxia syndrome (POS); that is, because intrapulmonary vascular dilations (IPVDs) predominate in the bases of the lungs, standing worsens hypoxemia (orthodeoxia)/dyspnea (platypnea) and the supine position improves oxygenation as blood is redistributed from the bases to the apices. Additionally, late in cirrhosis, it is common to develop high output failure, which would lead to less time in capillaries per red blood cell, exacerbating the hypoxemia. Diagnosis
The hepatopulmonary syndrome is suspected in any patient with known liver disease who reports dyspnea (particularly platypnea). Patients with clinically significant symptoms should undergo pulse oximetry. If the syndrome is advanced, arterial blood gasses should be measured on air.