Respiratory System Issues PDF 2024/2025

12/22/2024 Respiratory System Issues Medicinal I PC504 – Fall Semester 2024/2025 Prepared by Dr. Haydi Saher Elbordiny, PhD 2022 Table of contents 01 02 Bronchial Asthma...

12/22/2024 Respiratory System Issues Medicinal I PC504 – Fall Semester 2024/2025 Prepared by Dr. Haydi Saher Elbordiny, PhD 2022 Table of contents 01 02 Bronchial Asthma COPD 03 Cough and allergic rhinitis 1  12/22/2024 03 Drugs Used to Treat Respiratory Secretions and Cough Cough treatment antitussives Expectorant Mucolytics 2  12/22/2024 Cough Expectorants Antitussives and mucolytics I. Antitussives Benzonatate Dextromethorphan Codeine act peripherally (locally) to act centrally by inhibiting anesthetize the afferent the cough centers in the nerves that initiate the brain cough reflex 3  12/22/2024 Antitussives (Butylamino)benzoate derivative Benzonatate It is a non-opioid oral cough suppressant, or antitussive, with effects that last from six to eight hours. Since it is not an opioid benzonatate has no abuse liability. Uses: It is employed to reduce coughing in various respiratory conditions such as bronchitis, emphysema, influenza, and pneumonia. Mechanism of action: Benzonatate acts as (butylamino)benzoate derivative a local anesthetic, decreasing the sensitivity of stretch receptors( these receptors are mechanoreceptors responsive to distention of various organs and muscles ) in the lower airway and lung, thus reducing the drive to cough after taking a deep breath. Antitussives Codeine It is an opiate used to treat pain, as a cough medicine, and for diarrhea The general pharmacological action of codeine is similar to that of morphine, but with lower analgesic potency. The decreased potency also leads to a lower addiction compared with morphine. Side effects: respiratory depression, miosis, constipation, nausea, itching, dry mouth, and drowsiness. 4  12/22/2024 Antitussives Dextromethorphan Used as a cough suppressant in cough medicines It is sold in syrup, tablet, spray, and lozenge Example of PD discrimination of enantiomers Dextromethorphan Levomethorphan Antitussive Narcotic Analgesic Levorphanol acts mainly as an agonist of the μ-opioid receptor Antitussives The first pass through the hepatic portal vein results in some of the Metabolism of dextromethorphan c drug being metabolized by O- demethylation (by the cytochrome P450 enzyme) into an active metabolite called dextrorphan (DXO). DXO is the 3-hydroxy derivative of dextromethorphan. The therapeutic activity of dextromethorphan is due to be caused by both the drug and this metabolite. 5  12/22/2024 Expectorants Mucolytics Increase mucus secretion volume and/or hydration for more productive cough. Indirect-acting drugs: at low doses, some emetics can increase Reduce mucus viscosity by breaking respiratory mucus secretion by down tertiary structures within mucus inducing irritation in gastric mucosa (e.g. N-acetylcysteine). (reflex increase) e.g. Ipeca, ammonium chloride, potassium iodide, sodium citrate and ammonium acetate. Direct-acting drugs: they increase water secretion from mucosal glands Guaifenesin and Bromohexin. The latter has also mucolytic activity. Expectorant Guaifenesin Guaifenesin increases the volume of bronchial secretions and decreases mucus viscosity. This modulation of airway secretions enhances their clearance by promoting more effective expectoration. Guaifenesin may also have direct effects on respiratory tract epithelial cells, including suppressed mucin production, reduced mucus viscoelasticity, and improved muco-ciliary clearance (MCC). The risk of forming kidney stones during prolonged use can be reduced by maintaining good hydration and increasing the pH of urine. 6  12/22/2024 Mucolytics Bromhexine Ambroxol Bromhexine begins to act on the mucus at the formative stages in the glands inside the mucus-secreting cells. The drug induces the hydrolytic depolymerization of mucous protein fibers of high molecular weight disrupts the structure of acid mucopolysaccharide fibres in mucoid sputum and produces a less viscous mucus, which is easier to expectorate. Bromhexine helps in breaking down the mucopolysaccharide fragments and thus cause a reduction in sputum viscosity. Ambroxol is the demethylated active metabolite of Bromhexine. Ambroxol used in the treatment of respiratory diseases associated with viscid or excessive mucus. Mucolytics NAC hydrolyzes the disulfide bonds of mucus proteins to decrease mucus viscosity, thereby facilitating its clearance. It is also used in acetaminophen toxicity as it acts as a precursor for glutathione synthesis. to loosen thick mucus in individuals with cystic fibrosis or chronic obstructive pulmonary disease. It can be taken intravenously, by mouth, or inhaled as a mist. Acetylcysteine and its metabolite cysteine exert the mucolytic action through its free sulfhydryl group, which reduces the disulfide bonds in the mucus matrix and lowers mucus viscosity. 7  12/22/2024 03 Drugs Used to Treat allergic rhinitis 8