Chronic bronchitis asthma. Inhalers (MDI).

When you see someone carrying an inhaler, it a sure tell tale sign that person is an asthmatic. Inhalers or metered dosed inhalers (MDI) were first introduced in 1956 and ever since have become the mainstay treatment of asthma.

Most inhalers looked like an inverted L shaped. Inside an inhaler is a canister of medication and an actuator with a mouthpiece. The medication in the propellant is suspended in a mixture of liquid propellant gas and preservatives. In the past, inhalers used a mixture of CFC (chlorofluorocarbon) Freon gases. However, CFC is the leading reason for the ozone depleting effect on the earth’s atmosphere. So now inhalers are being replaced by a non CFC chemical called hydrofluoroalkane.

Medication in inhalers can primarily be divided into 2 types. Long acting and short acting Beta2-Agonists. Since asthma attack is characterized by narrowing of the bronchial tubes, short acting ones aims to reverse that process by opening up the airway. The longer acting ones are aimed at preventing future asthma attacks.

The standard treatment for short acting beta2-agonist is albuterol and goes under common brand names like Proventil and Ventolin. Similar medication include isoproterenol and metaproterenol. However, albuterol have side effects like headaches, sinus inflammation and dry throat.

To combat this side effect, a new drug Levalbuterol was developed. Levalbuterol is a recent new addition to a family number of short acting drugs. It goes under the brand name of Xepenex. Levalbuterol was initially introduced in liquid form given in dosage of 0.63mg and 1.25mg. Now a MDI form, Xenophax HFA was recently made available. All these drugs are made for rescue purpose and use only when needed

Two longer acting Beta2-adrenergic agonist drugs commonly found in inhalers are salmeterol and formoterol. These drugs have a longer duration of effect of up to 12 hours. They provided sustained dilatation of the bronchial rubes and gives better asthma control. These longer acting drugs are not without controversy.