Q. When are the beta-adrenergic agonists used? Which are the beta-agonists available in the market? What types of side-effects are associated with beta-agonists, and are they unsafe?
Uses of Beta-Adrenergic
Beta-agonists (beta-adrenergic agonists) can be taken in two ways:-
- On as-needed basis – like to treat asthma symptoms and to prevent exercise-induced asthma attacks.
- To control chronic asthma it is taken several times as part of a plan. And under such circumstances beta-agonists are taken in one or two puffs at regular intervals of four, six, eight or twelve hours, depending on the type of drug one takes. Doctor is the best person to specify the precise dosage and timing.
Benefits of Beta-Adrenergic
Beta-agonists that are sold in the market include
- Salbutamol which is most frequently used as an inhaled medication but also available as pills and formulations designed for use in a Nebuliser. It is available in the market as Volmax, Ventolin, Salamol and Aerolin.
- Fenoterol (Berotac) and pirbuterol (Exirel) available as metered-dose inhaler
- Tulobuterol (Respacal, Brelomax) which is available in pills and solution form, and
- Terbutaline (Bricanyl) which is available as a tablet, an injection, a metered-dose inhaler and a Nebuliser solution.
It is strange but true that certain people with asthma react better to one type of beta-agonist than others. One has to try the drug to know which one is best suited. Manufacturers are trying to develop new drugs that are more effective than the older ones. They are trying to develop beta-agonists that can work longer; salmeterol (Serevent) is the newest long-acting bronchodilator that can be taken twice a day.
Side Effects of Beta-Adrenergic Blockers
Like other drugs beta-agonists also have their side-effects. They include headache, nausea and vomiting, rapid heartbeat, anxiety and trembling. They however do not cause more trouble, and are common when people take oral forms of the drugs i.e., pills or syrups. But inhaled forms deliver the medication directly to the lungs and not to the blood so they have fewer side effects. In spite of this, oral and sometimes even inhaled beta-agonists may not be recommended for people with diabetes, heart problems or other medical conditions. Beta-agonists are unsafe if they are used more than four times a day. In 1990 a team of Researchers reported that asthma can worsen if beta-agonists are used over a long period.