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Mediator Modifiers |   |
The side-effects of antimuscarinics are minimal or absent in most patients using ipratropium, and systemic absorption via the GI tract and mucosal surface is also minimal. It has an additive effect to the Beta adrenergic agonists and, provides better bronchodilation for many COPD patients. It should be delivered prior to Beta agonists in order to achieve the best results.
Some other antimuscarinics include:
Glycoprrolate, a derivative of atropine which is usually administered parenterally, is used as an alternative to atropine because it has fewer ocular or central nervous system side effects. The injectable solution has been nebulized into a 1 mg dose for bronchodilation.
Oxitropium bromide is a derivative of scopolamine that has been investigated as an aerosolized anticholinergic bronchodilator in patients with obstructive airway disease. An MDI-delivered dose of 200 mcg provides a peak effect on FEV1 within 1-2 hours, with a duration of 6-8 hours. Normal dosage is 2 puffs BID or TID, and systemic anticholinergic effects are rare. Side effects include local irritation of the throat and nose, dry mouth, nausea, wheeze, cough, and a tightness in the chest in a few patients.
Tiotropium bromide is still an investigational, long-acting antimuscarinic drug that may offer an attractive and safe alternative for maintenance treatment of COPE, and protection for nocturnal asthma.
Mucokinetics
One of the major clearing and defense mechanisms of the airway- conducting zone of the lung is referred to as the mucociliary system. Mucokinetics is primarily concerned with the movement of mucus in the respiratory tract, and the overall effectiveness of the mucociliary system.
The effectiveness of the system depends largely on the interactions between the cilia and the mucus blanket, whose composition represents a delicate balance between the secretions of the goblet cells and bronchial glands. Failure of this system results in mechanical obstruction of the airway with thickened, adhesive secretions. A significant slowing of mucus transport is associated with the abnormal mucociliary function seen in bronchitis, asthma, and cystic fibrosis. Mucokinetic therapy is designed to maintain or improve functioning of the mucociliary mechanism, thereby promoting clearance of respiratory tract secretions and reducing the potential for infection.
Mucokinetic/mucolytic agents achieve their effect through a variety of ways, including:
- acting directly upon the chemical constituents of mucus to decrease mucus viscosity or tenacity
- diluting the mucus resulting in disadherence from the airway
- making the ciliary action more effective by replenishing or increasing the watery sol layer of mucus
- directly stimulating the cilia
- stimulating the bronchial glands to produce secretions that are less viscous
- a combination of several of these actions