Dilation drug-controlled releases

Sodium nitroprusside is used for the short-term control of severe hypertension and can improve cardiac function in patients with left ventricular failure see Chapter 34). Nitroprusside acts by releasing nitric oxide (NO). NO activates the guanylyl cyclase-cyclic GMP-PKG pathway, leading to vasodilation. The mechanism of release of NO likely involves both enzymatic and nonenzymatic pathways. Tolerance does not develop to nitroprusside. Nitroprusside dilates both arterioles and venules the hemodynamic response results from a combination of venous pooling and reduced arterial impedance. In subjects with normal left ventricular function, venous pooling affects cardiac output more than does the reduction of afterload cardiac output thus tends to fall. In patients with severely impaired left ventricular function and diastolic ventricular distention, the reduction of arterial impedance leads to a rise in cardiac output see Chapter 33). Sodium nitroprusside is a nonselective vasodilator, and regional distribution of blood flow is little affected by the drug. In... 

Based on these prior studies, a liposome-encapsulated drug carrier system has been developed in order to overcome fentanyls short dilation of action. Liposomes are microscopic vesicles composed of an aqueous compartment surroimded by a phospholipid bilayer that acts as a permeable barrier to entrap molecules. Incorporation of a drug within a hposome provides a controlled, sustained release system. 

Therapy of reversible airways disease Includes symptomatic relief of the attack, control of specific causative factors as well as generalized care of the patient. Drugs are employed to relax and dilate bronchioles (beta-sympathomlmetlcs and phosphodiesterase [PDE] inhibitors), reduce inflammation (steroids), liquefy mucus (acetylcysteine), decrease mucous membrane congestion (alpha-sympathomlmetics) and prevent mediator release (cromolyn sodium). Initial clinical studies of anticholinergics in asthmatics and bronchitics are under way. ... 

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