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ASTHMA AND THE CHRONIC PULMONARY DISEASE (COPD) MANAGEMENT. HISTORY Galen a Greek physician treated bronchial disorders by inhalations of salt at the seaside (mainly tuberculosis). Later the belladonna drugs , were used.
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HISTORY Galen a Greek physician treated bronchial disorders by inhalations of salt at the seaside (mainly tuberculosis). Later the belladonna drugs, were used. Atropa belladona and Datura stramondium, primary yields the alkaloid atropine The alkaloid scopolamine (hyoscin) is found in the srub Hyosciamus niger (henbane) and Scopolia carniolica. These alkaloids were inhaled by smoke from burning plants. In the 19th century antiasthmatic cigarettes containing atropin were used. It was a long time until the first metered dose inhalators appeared in 1956.
THE ADVANTAGES OF TREATMENT BY THE INHALES ROUTE: 1) high drug concentration reached at the side of the bronchi to be treated 2) failing systemic effects 3) the onset of bronchodilation is more rapid compared to oral administration
BASIC SYSTEMS CURRENTLY AVAILABLE FOR DELIVERING DRUG BY INHALATION (MDI). 1) Active systems that generates and releases aerosol to a patient. a) metered dose inhalers with or without the spacer. b) jet nebulizers producing a cloud of medication by passing a jet of compressed air over a solution of the drug. The less common ultrasonic nebulizers produce the cloud by dropping the solution into a plate, which vibrates at high frequency. 2) Passive systems require the effort of patient to generate and inhale the cloud. All dry powder inhalers (DPI) belong to this group.
Metered dose inhalers Advantages: relatively inexpensive, rather small and easy to operate. Disadvantages: the precise technique is needed, not recommended for circumstances as follows: for children < 5 years, people with handicap, elderly. The cloud can irritate the buccal mucosa, damage ozone layer.
Canister Metering chamber Actuator Aerosol
Spacers: Advantages: co-ordination of the breathe with the firing of the MDI is not important (thus convenient for children and elderly). Thus, the dose of drug can be enhanced, by increasing drug dosage and decreasing its systemic absorption. Spacers are inexpensive. Disadvantages: bulky and inconvenient, valves sometimes stick, damage to ozone layer.
Aerosol Plastic cone MDI Valve
Nebulizers: Advantages: easy to handle, convenient for patients on mechanical respiratory devices. Disadvantages: require the energy source and high dosage, not transportable (except new devices), Inhalation lasts for 15-20 min, requires high doses. Danger of infection if devices are not properly maintained, expensive.
Air supply Facial mask Usable aerosol Liquid inlet tube Baffle Liquit
Passive systems Dry powder inhalers. Advantages: function without freons, triggered by rapid inhalation, low weight, easily transportable, contains many doses. Disadvantages: inhalation dependent dose, humidity decreases the quantity of the cloud, soor (in concurrent use of glucocorticoids), hoarse voice, not recommended in children < 5 years, high cost
Drug administered by inhalation. A) IN PROPHYLAXIS - cromones - sodium cromoglycate (intal) - nedokromil sodium (tilade) - corticoids - beclomethason - (becotide, aldecin, beclomet, becodisk) - budesonide (pulmicort) - flunisolid (bronilide) - fluticason (flixotide)
B) FOR BRONCHODILATATION short-term (4-6 hours) - beta-2- mimetics - salbutamol (salbutamol, ventolin, ventodisk) - fenoterol (berotec) - terbutalin (bricanyl) long-term (12 hours) - beta-2- mimetics - salmeterol (serevent) - formoterol (oxis) - anticholinergics - ipratropium (atrovent) - oxitropium - tiotropium
Cromolyn sodium, nedocromil sodium they are only of value when taken prophylactically no effect on airway smooth muscle tone - are ineffective in reversing bronchospasm poorly absorbed from GIT - they must be applied topically, by inhalation of a microfine powder or aerosolized solution. Mechanism of action inhibiting cellular activation ( delayed Cl channels) inhibition mast cell degranulation ? Inhibition of phosphodiesterase
Consequences blocks bronchoconstriction chronical treatment with cromolyb causes a decrease in bronchial hyperreactivity, perhaps by protecting the airways against the inflamarory effects of the chemical mediators of anaphylaxis Clinical use prophylactically in asthma especially young patients allergic rhinitis hay fever
Adverse effects So poorly absorbed, adverse effects of cromolyn are minor and are localized in the sites of deposition as throat irritation, cough, mouth dryness, chest tightness, and wheezing. Nedocromil appears to have greater inhibitory activity on primate lung mast cells in vitro. It can offer greater antiasthmatic potency than cromolyn.