Antitussive Effects

The opioids block cough by a mechanism that is not yet understood. No stereoselectivity of the opioids for blockade of the cough reflex has been shown. Thus, the isomers of opioids, such as dextrorphan, are as efficacious as the l-isomers as antitussives. This lack of stere-oselectivity prompted the development of the d-isomers of opioids as antitussives since they are devoid of the dependence liability of L-isomers. Drugs with predominantly antitussive effects are described later in this chapter. Certain of the opioids, such as propoxyphene and meperidine, are relatively devoid of antitussive effects.

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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