Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Erectile dysfunction medications such as sildenafil citrate (Viagra) or tadalafil (Cialis) are commonly prescribed worldwide. They are selective phosphodiesterase-5 inhibitor and partial phosphodiesterase-6 inhibitors causing smooth muscle relaxation in the corpus cavernosum, allowing penile vasodilatation and erection in response to sexual stimuli. Over the years, there have been an increasing number of case reports concerning patients who developed ischemic optic neuropathy soon after the ingestion of these drugs. Although a cause and effect relationship between usage of the drugs and the development of ischemic optic neuropathy is difficult to prove, it is common nowadays to advise patients, especially those suffering from diabetes, hypertension, and ischemic heart disease, regarding the potential risk of visual loss due to ischemic optic neuropathy and treatment with erectile dysfunction drugs. Patients who were diagnosed with ischemic optic neuropathy soon after the ingestion of these erectile dysfunction drugs should be warned about a similar event in their fellow eye and should be advised regarding drug discontinuation.
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PMID:[Non-arteritic anterior ischemic optic neuropathy associated with erectile dysfunction medications]. 2351 98

Type 2 diabetic men commonly experience erectile dysfunction for which phosphodiesterase-5 (PDE5) inhibitors like sildenafil (Viagra) are often recommended. By preventing degradation of cyclic guanosine monophosphate (cGMP) in vascular smooth muscle, these inhibitors also enhance arterial vasorelaxant effects of nitric oxide donors (which stimulate cGMP synthesis). In the present work, we confirmed this enhancing effect after co-administration of sildenafil with nitroprusside to freshly-isolated rat tail arterial tissues. However, in the same tissues we also observed that sildenafil does not enhance but rather attenuates vasorelaxant effects of three commonly-used antidiabetic drugs, i.e. the biguanide metformin and the thiazolidinediones pioglitazone and rosiglitazone. Indeed, sildenafil completely blocked vasorelaxant effects of low concentrations of these drugs. In addition, we found that this same novel anti-vasorelaxant interaction of sildenafil with these agents was abolished by either 1) omitting extracellular glucose or 2) inhibiting specific smooth muscle glycolytic pathways; pathways known to preferentially utilize extracellular glucose to fuel certain adenosine triphosphate (ATP)-dependent ion transporters: e.g. ATP-sensitive K channels, sarcoplasmic reticulum Ca-ATPase, plasma membrane Ca-ATPase and Na/K-ATPase. Accordingly, we suspect that altered activity of one or more of these ion transporters mediates the observed attenuating (anti-vasorelaxant) interaction of sildenafil with the antidiabetic drugs. The present results are relevant because hypertension is so common and difficult to control in Type 2 diabetes. The present data suggest that sildenafil might interfere with the known antihypertensive potential of metformin and the thiazolidinediones. However, they do not suggest that it will interact with them to cause life-threatening episodes of severe hypotension, as can occur when it is co-administered with nitrates.
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PMID:Sildenafil does not enhance but rather attenuates vasorelaxant effects of antidiabetic agents. 2600 78

Inhibitors of phosphodiesterase 5 (PDE5) - sildenafil citrate (Viagra; Pfizer) and vardenafil hydrochloride (Levitra; Bayer/GlaxoSmithKline) - approved for the treatment of erectile dysfunction and pulmonary arterial hypertension also rescue the loss of cystic fibrosis (CF) chloride channel function and the mislocalization of F508del-CFTR in affected tissues in CF. Can PDE5 inhibitors provide a therapeutic strategy which combines ability to correct the basic ion transport defect and to control de-regulated lung inflammation in CF?
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PMID:Classical activation of macrophages and vardenafil. 2819 56

Sildenafil citrate (Viagra) is used to treat erectile dysfunction and pulmonary arterial hypertension. The objective of this study was to analyze the action of sildenafil citrate on normal human erythrocytes in vitro at a concentration (2.5 mg/mL) higher than the prescribed for clinical conditions. Imaging of drug-treated erythrocytes was done using an atomic-force microscope in contact mode in air. Data analysis was performed using the scanning probe-microscopy software WSxM. The study revealed that the drug causes hemolysis of erythrocytes at high concentration in vitro at room temperature. The ghosts (membranes) of erythrocytes with reduced cell size and deformed shape were observed using atomic force-microscope imaging at low magnification. In addition, the high-magnification images revealed alterations in the nanostructural features of the erythrocyte membrane. There was a complete loss of characteristic membrane-architecture pattern. The root-mean-square surface roughness of the cell membrane after drug treatment was measured and found to be significantly less than that of erythrocytes in the native state. Sildenafil citrate causes hemolysis of erythrocytes in vitro at high concentration with significant alterations in morphometric properties, like change in cell shape, reduction in cell dimension, and disruption of membrane cytoarchitecture, along with a severe drop in membrane root-mean-square surface roughness.
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PMID:Sildenafil citrate (Viagra) reduces surface roughness of human erythrocytes: Atomic-force-microscopic study. 3002 11


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