Cold remedies, decongestants

The principal OTC pharmaceutical products include cold remedies, vitamins and mineral preparations, antacids, analgesics, topical antibiotics, antiftingals and antiseptics, and laxatives. Others include suntan products, ophthalmic solutions, hemorrhoidal products, sleep aids, and dermatological products for treatment of acne, dandmff, insect parasites, bums, dry skin, warts, and foot care products (11). More recent prescription-to-OTC switches have included hydrocortisone, antihistamine and decongestant products, antiftingal agents, and, as of 1995, several histamine H2-receptor antagonists. 

A Assign R or 5 configuration to each chirality center in pseucloephedrine, an over-the-counter decongestant found in cold remedies (blue = N). 

Do not use OTC products containing a-adrenergic stimulants (nasal decongestants, cold remedies) unless directed by physician... 

Assign A or configuratiiMi o chirabty center ui pi eudoephedriii9. i th to iiiter decongestant twnA in cold remedies fred - O, blim - N. ... 

A few oral forms of decongestants are available for example, pseudoephedrme (Sudafed), a close relative of the natural stimulant ephedrinc. Since it goes into the mouth rather than the nose, it is less likely to CLiuse rebound and dependence, but for some people and in high doses it is definitely a stimulant. Our old friend phenylpropanolamine is often identified as an oral decongestant when it appears in OTC cold remedies and cough syrups> of course, it, too, is a stimulant. 

Pseudoephedrine is used for its vasoconstrictive properties (a-adrenergic action) as a nasal decongestant in a wide variety of cold remedies. Both lR,lS )-ephedrme and IS,IS(-t)-pseudoephedrine have been popular starting products for the synthesis of S(+)-methamphetamine. Because of this, the quantity per purchase of products containing these drugs is now restricted. 

No interaction between phenylephrine and the beta blockers would be expected, and apart from the single unexplained case cited above, the literature appears to support this. Concurrent use normally appears to be clinically unimportant, particularly bearing in mind the widespread use of beta blockers and the ready availability of phenylephrine in the form of non-prescription cough-and-cold remedies and nasal decongestants. 

Practitioners should be aware of over-the-counter (OTC) medications and folk or home remedies that patients may be using. Many patients may not consider OTC agents, especially antihistamines and decongestants for hay fever and colds, as drugs. These can affect the autonomic nervous system. OTC preparations can potentially interact with ocular drugs, such as homatropine and phenylephrine, that also influence autonomic functions. 

Since there are two possible configurations for an asymmetrically substituted carbon atom, a structure containing n such centres will, in theory, possess 2 stereoisomers. The actual number of stereoisomers that exist may be less than this due to steric effects. Compounds that have the same stereochemistry at one chiral centre but different stereochemistry at the others are known as diastereoisomers (diastereomers) a good example is given by the alkaloids ephedrine and pseudoephedrine. Ephedrine (the (1R, 2S) diastereoisomer) is a natural product isolated from Ephedra (the Ma Huang plant) and known to Chinese medicine for over 3000 years. It was used in the last century for the treatment of asthma. Pseudoephedrine (the (IS, 2S) diastereoisomer) is a decongestant and a constituent of several over-the-counter cold and flu remedies (Figure 4.12). 

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