Drug profile Essay Example | Topics and Well Written Essays - 2000 words

Drug profile - Essay Example Indications: - bronchial asthma (RACGP, 2006; Lullman et al., 2000), - bronchitis (RACGP, 2006) - exercise-related dyspnea (RACGP, 2006) - other breathing problems (RACGP, 2006). - pre-term labour (Morgan et al., 1987). According to the Medical Reference Manual by Adult Retrieval Victoria (2011), Salbutamol (5-10 mg or 8 puffs 10-15 minutely) is one of the standard therapies for refractory asthma. Continuous nebulised Salbutamol is also used for maximum pre-intubation therapy. As well, the Queensland Ambulance Service (2011) lists approved emergency indications as bronchospasm and suspected hyperkalaemia with QRS widening and/or AV dissociation (Medical Director’s Office 2011 p. 69) for adult and paediatric administration (p. 70). Contraindications against paramedic use of salbutamol have been reported to include potential synergism with other sympathomimietics. It should also be used with caution in patients with diabetes, hyperthyroidism, and cerebrovascular disease (Albuter ol 1999, p. 1). List of drug-drug interactions with Salbutamol (Albuterol 2011) Medicine name Strength Atomotexine – may cause CVS effects such as tachycardia and hypertension case reports Digitalis – hypokalemia induced by salbutamol may cause cardiac glycoside toxicity Mechanism already elucidated Diuretics – hypokalemia Steroids – hyperglycemia or hypokalemia Sympathomimetics – additive effects Theophylline – additive effects Xanthine derivatives –hypokalemia Bendrofluazide – augments hypokalemia, cardiac effects, arrhythmia Signal Transduction Mechanisms for ?2 Receptors Figure 1.The messenger system starting with the activation of receptor, which stimulates the G-protein to dissociate into its subunits. The ?-subunit then activates the enzyme converting ATP to cAMP. Figure from Guyton, A. C. and Hall, J. E. 2006. Textbook of Medical Physiology. Philadelphia: Elsevier. Salbutamol is an agonist of the beta 2 adrenergic recep tors found on the smooth muscle lining airways of the lungs (Lullman, 2000). The intracellular components of the receptor are associated with G protein. In turn, G protein has three sub units (alpha sub unit, plus tightly associated beta, and gamma sub units). Upon binding of salbutamol to ?2 receptor, the latter activates the G protein, causing GDP (guanosine 5'-diphosphate) associated with the G protein to be phosphorylated to GTP (guanosine 5'- triphosphate), which initiates detachment of alpha subunit. The alpha subunit binds with adenylyl cyclase, which catalyses the conversion of ATP to cAMP (adenosine 5'-triphosphate to adenosine 3',5'-monophosphate) (Guyton and Hall, 2006). cAMP then inhibits myosin light chain kinase which is responsible for the contraction and hence constriction of bronchial smooth muscle (Klabunde, 2008). The inhibition of myosin light chain kinase promotes the physical relaxation and hence dilation of the smooth muscle lining of the affected airways whic h improves the potential for improved respiration which is key to addressing several pulmonary disorders Evidence of Clinical Effectiveness Despite being the most used ?2-agonist, research on the clinical effectiveness of Salbutamol had contradicting results. In a randomized control trial on salbutamol against preterm labor, 100 women, ages 17-32 years old and between 20-37 weeks pregnant, were recruited.