cough drop

A small, often medicated and sweetened lozenge taken orally to ease coughing or soothe a sore throat.

A cough drop is medicinal tablet designed to deliver active ingredients which suppress or relieve the cough reflex. They are made just like hard candies; ingredients are mixed together, they are cooked, cooled, and packaged. First developed during the eighteenth century, cough drops have become a significant part of the $2 billion cough and cold market.

Background

Anyone who has gotten sick knows the sensation of a cough. It is a natural reflex that helps protect the body from infections. It plays an important role in clearing the throat and other air passages of secretions and irritating particles. These particles include dust, food, liquids, and mucus. A cough occurs in three distinct steps. It typically begins with a deep breath which draws air into the lungs. The vocal cords spontaneously close thereby sealing the windpipe. Next, the air is compressed by the tightening of the expiratory muscles. The vocal cords are suddenly opened and the air trapped in the lungs is rapidly expelled along with any foreign debris in the windpipe.

Coughs associated with colds can be either productive or nonproductive. A productive cough helps clear the respiratory passages of the lung. A nonproductive cough is brought on by a minor irritation and has a limited benefit. It is the nonproductive cough that cough drops are designed to sooth or suppress.

The are two types of active ingredients in a nonprescription cough drop including expectorants and cough suppressants. An expectorant is a material that aids in the removal of phlegm from the respiratory tract. It works by blocking the sensory nerves that are involved in triggering a cough. While many expectorants are available, data about their functionality is not. Some clinicians even question whether expectorants are effective. Antitussives, which are cough suppressants, work in a variety of ways affecting either the lungs, muscles, or brain.

History

Using syrups and herbal teas to control coughing has been known since antiquity. An ancient Hebrew text suggests the use of goat's milk for this reason. In the second century, Galen was perhaps the first to report an effective cough suppressant. Cough drops originally developed from candy. The first hard candies were produced during the fourth century. Since sugar was so expensive, these products were typically a luxury item available only to the rich. Over the years, sugar crops were planted in North America and throughout the world. Sugar refiners were established, and the price of sugar was reduced, making it available to everyone by the eighteenth century.

While the active ingredients in a cough drop were known for centuries, it was not until the nineteenth century that the cough drop was born. One of the first mass-produced cough drops was the Smith Brothers cough drop. According to the company, James Smith was operating a restaurant when a journeyman introduced him to a formula for a cough candy. He mixed up a batch in his kitchen and was able to quickly sell them. Demand for his product grew and he began advertising in 1852. He enlisted the aid of his two sons who helped mix batches and sell them on the streets of Poughkeepsie, New York. They inherited the business in 1866 when James Smith died, and renamed the company Smith Brothers. During this time, they sold their cough drops in large glass bowls. To prevent imitators, they developed a unique package in 1872 that was filled at the factory. In 1922, menthol cough drops were introduced. Over the years, a variety of manufacturers have developed their own cough drop formulas. Each one has tried to improve the flavor and efficacy of their product.

Raw Materials

Cough drops have two categories of ingredients. One type makes up most of the cough drop while the other is the active, or functional, ingredients. The major portion of cough drops is made up of ingredients found in typical hard candy recipes. The essential ingredients include sugar, corn syrup, acids, colors, and flavors. Sugar is a disaccharide compound called sucrose. It is obtained primarily from sugarcane or sugar beets by an extraction process. In a cough drop recipe, sugar crystals are usually used. Sugar is responsible for the physical structure of the cough drop along with its sweet taste and mouthfeel.

Corn syrup is a main component of cough drops. It is a mixture of sugars that is composed of polysaccharides, dextrose, and maltose. The main reason it is used is to control the crystallization of sugar. It also provides some sweetness and body to the cough drop. Additionally, it reduces the formation of dust from sugar during the blending stage.

To increase the visual appeal of the cough drop various dyes are added. In the United States, these dyes are strictly regulated by the government. Some that are allowed in food products include red dye #40, yellow dye #5, yellow dye #6, and blue dye #1. Natural colorants like caramel coloring are also used. Using only these colorants, the most popular cough drop colors, red and blue, can be produced.

To cover the taste of the active ingredients, various flavoring ingredients are put into cough drop recipes. Both artificial and natural flavors are used. Artificial flavors are mixtures of aromatic chemicals like methyl anthranilate and ethyl caporate. Natural flavors are derived from fruits, berries, and honey. Acids such as citric, lactic, tartaric, and malic acid are also included to modify the flavor.

Various active ingredients can be included in a cough drop recipe. As mentioned previously, these can be either expectorants or antitussives. Some common ingredients are volatile oils such as menthol or eucalyptus oil. Volatile oils, or essential oils, are obtained from parts of a plant through extraction or distillation processes. Menthol is typically isolated from the Mentha arvensis plant or distilled from peppermint oil. It may also be synthetically produced. Menthol has a cooling effect in the mouth that helps to relieve irritation. It is also thought to work as an expectorant. Eucalyptus oil is isolated from the eucalyptus plant. It is believed to have a medicinal effect functioning as an expectorant and a relief agent for minor mouth and throat irritations. Recently, companies have been including zinc in their cough drops. Certain evidence suggests that zinc may be beneficial in fighting symptoms of a cold. Vitamin C is another ingredient that has been included in some brands of cough drops. Other ingredients that may be found are herbals such as echinacea or ginko biloba. Peppermint oil, camphor, and sodium citrate have also been used.

Design

Cough drops, or lozenges, are usually sold as small, hard candy pieces that slowly release their medicine as they melt in the mouth. Chemically speaking, they are a supersaturated solution of water molecules, sugar, and corn syrup. They can be either grained (opaque) or nongrained (clear). While all cough drops are designed to sooth and relieve coughing, some have added ingredients to help fight colds, freshen breath, or clear nasal congestion. Certain cough drops have reduced active ingredients and are created specifically for children. There are a wide variety of flavors, the most popular of which are cherry, honey, and menthol.

The Manufacturing
Process

The basic steps in producing a cough drop are mixing, cooking, cooling-working, forming, cooling, and packaging. Most manufacturers have an automated production line connected by a conveyor system.

Mixing

• In this manufacturing step, the ingredients are combined in a large, stainless steel container by compounding personnel. Water is usually pumped directly in to the tank. The sugar, corn syrup, and certain other ingredients are then mixed until they are ready to be cooked.

Cooking

• To produce the cough drop, the moisture level of the mixture must be reduced. Some cough drops have a moisture content as low as 0.5%. There are three types of cookers that are employed. Batch cooking involves a direct-fire cooker. In this method, the heat is applied to the mixture from below and the moisture evaporates into the air. Quicker methods use either a semicontinuous cooker or a continuous cooker that operates under low pressure conditions. In the semicontinuous process, the cough drop mixture is first boiled under atmospheric pressure and then pumped into a second kettle that is a vacuum chamber. It is then rapidly cooked and drawn off for working. Continuous cookers use a scraped-surface heat-exchanger which can cook the cough drop within a few seconds.

Cooling and working

• After cooking, the cough drop mixture is conveyored to cooling slabs. It is cooled to facilitate incorporation of ingredients such as color, flavors, and active ingredients. The cooling slabs are composed of steel and have a built-in circulating water system. Candy plows are also involved. They move the mixture around so some of the hotter areas come in contact with the cooler surface of the slabs. As it cools, the mixture becomes plasticized and it looks like a workable mass similar to dough.
• At this point, the rest of the cough drop ingredients are added. They are poured onto the batch and machines pull and twist the mass, working the ingredients throughout. When everything is adequately combined, the batch is split off and sent through a sizing machine. These devices roll the batch into a cylindrically shaped mass and reduce the diameter to a suitable size. From here, the mass is fed into the forming machines.

Forming

• Various forming machines are available. Typically, cough drops are tablet-shaped products. The cylindrical mass runs through this machine and is cut into smaller pieces. These pieces are then put into a die and stamped to produce the desired shape. The cough drops are then ejected from the die and moved to the finishing phases of production.

Cooling and packaging

• The formed cough drops are rapidly cooled to ensure that they maintain their shape. This is done on a conveyor belt that is equipped with rapidly blowing air jets. From the cooling area, the cough drops are put into packaging. Many manufacturers wrap each cough drop in a wax paper package to prevent them from absorbing moisture from the air. A number of these are then put into a larger bag for final sales. Other manufacturers do not individually wrap their cough drops, but store them in a bulk package. These are typically a wax-coated box that is sealed. To prevent them from sticking together, bulk packaged cough drops are often coated.

Quality Control

As with all food and drug processing facilities, quality control begins by monitoring the characteristics of the incoming ingredients. These ingredients are taken to a quality control lab where they are tested to ensure they meet specifications. Tests include evaluation of the ingredient's physical properties such as appearance, color, odor, and flavor. Certain chemical properties of the ingredients may also be evaluated. Each manufacturer has their own tests that help certify that the incoming ingredients will produce a consistent cough drop. In addition to ingredient checks, the packaging is also inspected to ensure it meets the set specifications.

After production, the characteristics of the final product such as appearance, flavor, texture, and odor are also carefully monitored. The usual test methods involve comparing the final product to an established standard. For example, to make sure the flavor is correct, a random sample may be taken and compared to some set standard. Other qualities such as appearance, texture, and odor may be evaluated by sensory panels, a group of specialists that are trained to determine small differences. In addition to sensory tests, other instrumental measurements are taken.

The Future

Cough drop recipes have changed little since they were first introduced. Most of the advancements have come in the design of the cookers and other processing equipment. It is expected that future improvements aimed at increasing the speed of production will continue to be found. Another area that will be expanded will be the addition of novel ingredients that may provide multiple benefits to the consumer. For example, some cough drop marketers have introduced vitamin C-containing products. These cough drops are intended not only to sooth a cough, but also relieve some of the symptoms of a cold.

Where to Learn More

Books

Alikonis, J. Candy Technology. Westport, CT: AVI Publishing Co., 1979.

Covington, T. Handbook of Nonprescription Drugs. Washington, DC: American Pharmaceutical Association, 1993.

Mathlouthi, M. and P. Reiser, eds. Sucrose: Properties and Applications. London: Blackie and Sons, Ltd., 1995.

Periodicals

Friedman, M. "As Temperatures Drop, Cough Remedies Flourish." Adweek (February, 1989).

Slezak, M. "Warm Weather Cools Cough and Cold Sales." Supermarket News (March 6, 1995).

[Article by: Perry Romanowski]

A small, often medicated and sweetened lozenge taken orally to ease coughing or soothe a sore throat.

The noun has one meaning:

Meaning #1: a medicated lozenge used to soothe the throat
  Synonyms: troche, pastille, pastil

Cough medicine often contains cough suppressants or expectorants.

A cough medicine is a medicinal drug used to treat coughing and related conditions. Dry coughs are treated with cough suppressants (antitussives) that suppress the body's urge to cough, while productive coughs (coughs that produce phlegm) are treated with expectorants that loosen mucus from the respiratory tract. These medicines are widely available in the form of cough syrup, also known as linctus.

Contents 1 Examples 2 Effectiveness 3 Mass poisonings due to diethylene glycol 4 Botanical sources 5 See also 6 References 7 External links

Examples

This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2008)

Codeine is one of the strongest cough suppressants known, along with a number of derivatives such as the dihydrocodeine-hydrocodone subgroup of opioids, and the semi-synthetics and synthetics mentioned below. Codeine is the standard by which all antitussives are measured. It suppresses coughing by direct action on the cough centre in the brain, and also decreases the rate and/or tidal volume of respiration. The below-mentioned semi-synthetics differ from codeine in such ways as lipid solubility and CNS penetration, overall side-effect profile, and duration of action.

Natural and semi-synthetic opiates with antitussive effects include codeine, ethylmorphine (also known as dionine or codethyline), dihydrocodeine, benzylmorphine, laudanum, dihydroisocodeine, nicocodeine, nicodicodeine, hydrocodone, hydromorphone, acetyldihydrocodeine,diamorphine (heroin), acetylmorphone, noscapine and pholcodine and others.

Laudanum, also known as Deodourised Tincture of Opium and Denarcotised Opium Tincture due to the removal of narcotine, an opium alkaloid which causes nausea, is a whole-opium preparation which has both morphine and codeine in it in addition to other alkaloids which relax smooth and striated muscles. It is of value in cases where the disease is causing other problems for the patient which could benefit from the actions of morphine. Laudanum is still manufactured and used throughout the world at present although it is more common to use paregoric (several times more dilute than laudanum), solid forms of opium, or alkaloid mixtures such as pantopon. Morphine by itself has marginal antitussive properties.

Noscapine and pholcodeine are natural opium alkaloids which have some antitussive effect and tend not to have a full spectrum of narcotic effects and low or non-existent physical dependence or addiction liability; preparations thereof are often available over the counter in many countries. Noscapine is used less often these days and has been removed from the standard recipe for pantopon, omnopon and similar opium alkaloids salts preparations in many pharmacopeias because of concerns about carcinogenicity a number of years ago and clinical experience that noscapine is not a necessary or effective component of pantopon-type drugs.

Ethylmorphine is almost identical to codeine in effects and chemistry and is in structure the closest relative of codeine (codeine is also known as methylmorphine). Both ethylmorphine and codeine are partially changed to morphine in the liver.

Benzylmorphine (Peronine), is also closely related to codeine and the strong opioid analgesic myrophine.

Dihydrocodeine, a close chemical relative of codeine which is usually the number-two prescription narcotic antitussive in countries in which hydrocodone is not available, is related to the strong opioid dihydromorphine in the same way codeine is to morphine and a percentage of it is changed to dihydromorphine in the liver. Dihydrocodeine is base of a number of other semi-synthetic opioids, many of which are also effective antitussives.

Hydrocodone (Codiclear, Dicodid, and many others, also Vicodin and other analgesic preparations) is a semi-synthetic ketone about three times stronger than codeine which is related to another powerful analgesic and antitussive, hydromorphone (Dilaudid) in the same way codeine is to morphine; the liver changes a percentage of hydrocodone into hydromorphone.

Hydromorphone itself is marketed as cough syrups and elixirs for dry, violent, painful coughing as Dilaudid Cough Syrup and under other brand names and the generic hydromorphone hcl syrup. Both hydromorphone and hydrocodone are demonstrably stronger antitussives than codeine in most patients and will have some activity in those who cannot metabolise codeine at all because of other medications taken at the same time or unusual absolute and relative levels of the various Cytochrome P-450 liver enzymes.

Nicocodeine is related to the strong analgesic nicomorphine (Vilan) in the same way.

Dihydroisocodeine is chemically similar to isocodeine.

Acetylated semi-synthetics, which differ from the drugs from which they are derived chiefly by entering the central nervous system more rapidly and being stronger on a millgramme basis include thebacon (related to hydrocodone), diamorphine, aka diacetylmorphine and heroin, (related to morphine), acetylmorphone (related to hydromorphone), acetyldihydrocodeine (related to dihydrocodeine), diacetyldihydromorphine (related to dihydromorphine).

The very popular antitussive dextromethorphan is related to the dextrorotary form of dromoran and is not an opioid but a NMDA antagonist. It is changed to dextrorphan in the liver.

The antitussive tipepidine is an opioid drug of the thiambutene group. The protoypes of this family of opioids, thiambutene, methylthiambutene, and ethylmethylthiambutene, are, like tipepidine, most commonly used in Pacific Rim and East Asian countries as both human and veterinary analgesics. Tipepidine is available in some locations OTC although in South Korea and elsewhere it is watched more carefully as it has become a drug of abuse because of the purported psychedelic effects of high doses due to its apparent action on sigma receptors and kappa and perhaps delta opioid receptors, the NMDA system, and anticholinergic effects.^{[citation needed]}

Drugs of the open-chain (methadone) type with antitussive efficacy include methadone, levomethadone, normethadone, and levopropoxyphene, and the more distant relative isoaminile. Methadone Linctus is a liquid preparation of methadone hydrochloride (or less frequently methadone tartrate) used for cough suppression and analgesia which is about one-third the concentration of methadone used for maintenance treatment. Cough syrups containing levopropoxyphene are widely-used in many countries and in many of them have an OTC status similar to that of dextromethorphan.

It is possible that other classes of opioids may have cough suppressants amongst them as well since the effect is the result of the action of the drug on a specific receptor in the central and peripheral nervous systems.

Diphenhydramine and its derivatives are often useful as non-narcotic cough suppressants by themselves and they dry out bronchial secretions, boost the effects of opioids and combat cold/allergy symptoms caused by immune responses which release histamine into the system. Like many of the classical first generation antihistamines, it also boosts the effects of most opioids, with the result that the dose of codeine and other centrally-acting antitussives can be reduced. Because of the drying effect, diphenhydramine may not be ideal for dry coughs and antihistamines of the cyclizine group (Marezine (cyclizine), Dramamine II (meclizine), Atarax and Vistaril (hydroxyzine) and buclizine and others) would be good substitutes for diphenhydramine for use as an opioid potentiator as are cyproheptadine (Periactin) and phenindamine (Nolahist and Thephorin).

Effectiveness

In 2001, researchers at the University of Bristol (Schroeder & Fahey) published the results of their meta analysis in the British Medical Journal indicating that some cough medicines may be no more effective than placebos for acute coughs in adults, including coughs related to upper respiratory tract infections.^[1] In 2006, the American College of Chest Physicians published a guideline that had the dual message that many over-the-counter cough medicines are not effective and that those that are effective in treating the symptom do not treat the underlying cause; the underlying disorder emphasized by the guideline was pertussis (whooping cough) in the elderly.^[2].

The efficacy of cough syrups for children has long been questioned by medical professionals. A report in pharmaceutical journal Australian Prescriber found that although tests results for efficacy were inconclusive for children over 2 years of age, a number of factors including accidental overdoses and well-documented adverse effects suggested caution in the paedriatic prescription of cough syrups and medicines^[3].The report also noted that efficacy in children under two years was extremely limited and strongly recommended against prescription to this group based on the aforementioned health risks.

Recent studies have found that theobromine, a compound found in cacao, is more effective as a cough suppressant than prescription codeine. This compound suppresses the "itch" signal from the nerve in the back of the throat that causes the cough reflex. It is possible to get an effective dose (1 g, though 0.5 g may be sufficient)^[4] from 50g of dark chocolate, which contains 2 to 10 times more cacao than milk chocolate. Cocoa powder contains roughly 0.1 g per tablespoon (5g).^[5] Theobromine was also free from side effects in the blind tests.^[6]

Mass poisonings due to diethylene glycol

Main article: Toxic cough syrup

According to the New York Times, at least eight mass poisonings have occurred as a result of counterfeit cough syrup, substituting inexpensive diethylene glycol in place of glycerin. In May 2007, 365 deaths were reported in Panama, which were associated with cough syrup containing diethylene glycol.^[7]

Botanical sources

• Sunflower (expectorant)^[8]

See also

• Cough drop

References

1. ^ Knut Schroeder and Tom Fahey (2002). "Systematic review of randomised controlled trials of over the counter cough medicines for acute cough in adults". British Medical Journal 324: 329–331. doi:10.1136/bmj.324.7333.329. PMID 11834560. http://bmj.bmjjournals.com/cgi/content/full/324/7333/329. 
2. ^ American College of Chest Physicians (January 9, 2006). "New Cough Guidelines Urge Adult Whooping Cough Vaccine; Many OTC Medications Not Recommended for Cough Treatment". Press release. http://www.chestnet.org/about/press/releases/2006/010906a.php. 
3. ^ Sung, Valerie and Cranswick, Noel (2009). "Cough and cold remedies for children". Australian Prescriber, Vol. 32.pp 122-124. Available at http://www.australianprescriber.com/upload/pdf/articles/1047.pdf.
4. ^ Usmani OS, Belvisi MG, Patel HJ, et al. (February 2005). "Theobromine inhibits sensory nerve activation and cough". The FASEB journal: official publication of the Federation of American Societies for Experimental Biology 19 (2): 231–3. doi:10.1096/fj.04-1990fje. PMID 15548587. http://www.fasebj.org/cgi/pmidlookup?view=long&pmid=15548587. 
5. ^ Chocolate Products - Nutritional Information - HERSHEY'S
6. ^ Vince, Gaia (November 22, 2004). "Persistent coughs melt away with chocolate". New Scientist. http://www.newscientist.com/article.ns?id=dn6699. 
7. ^ From China to Panama, a Trail of Poisoned Medicine - New York Times
8. ^ Hoffmann, David (March, 1988). The Complete Illustrated Holistic Herbal (Rev ed.). Element Books. ISBN 978-1852300241. 

External links

• Cough medicines not helpful - from CNN.com

v • d • e Pharmacology: Major drug groups Gastrointestinal tract/metabolism (A) stomach acid (Antacids, H2 antagonists, Proton pump inhibitors) • Antiemetics • Laxatives • Antidiarrhoeals/Antipropulsives • Anti-obesity drugs • Anti-diabetics • Vitamins • Dietary minerals Blood and blood forming organs (B) Antithrombotics (Antiplatelets, Anticoagulants, Thrombolytics/fibrinolytics) • Antihemorrhagics (Platelets, Coagulants, Antifibrinolytics) Cardiovascular system (C) cardiac therapy/antianginals (Cardiac glycosides, Antiarrhythmics, Cardiac stimulants) Antihypertensives • Diuretics • Vasodilators • Beta blockers • Calcium channel blockers • renin-angiotensin system (ACE inhibitors, Angiotensin II receptor antagonists, Renin inhibitors) Antihyperlipidemics (Statins, Fibrates, Bile acid sequestrants) Skin (D) Emollients • Cicatrizants • Antipruritics • Antipsoriatics • Medicated dressings Reproductive system (G) Hormonal contraception • Fertility agents • SERMs • Sex hormones Endocrine system (H) Hypothalamic-pituitary hormones • Corticosteroids (Glucocorticoids, Mineralocorticoids) • Sex hormones • Thyroid hormones/Antithyroid agents Infections and infestations (J, P, QI) Antibiotics (Antimycobacterials) • Antifungals • Antivirals • Antiparasitics (Antiprotozoals, Anthelmintics) • Ectoparasiticides • Intravenous immunoglobulin • Vaccines Malignant disease (L01-L02) Anticancer agents (Antimetabolites, Alkylating, Spindle poisons, Antineoplastic, Topoisomerase inhibitors) Immune disease (L03-L04) Immunomodulators (Immunostimulants, Immunosuppressants) Muscles, bones, and joints (M) Anabolic steroids • Anti-inflammatories (NSAIDs) • Antirheumatics • Corticosteroids • Muscle relaxants • Bisphosphonates Brain and nervous system (N) Anesthetics (General, Local) • Analgesics • Antimigraines • Anticonvulsants/Mood stabilizers (Lithium pharmacology) • Antiparkinson drugs Psycholeptics (Anxiolytics, Antipsychotics, Hypnotics/Sedatives) • Psychoanaleptics (Antidepressants, Stimulants) Respiratory system (R) Decongestants • Bronchodilators • Cough medicines • H1 antagonists Sensory organs (S) Ophthalmologicals • Otologicals Other ATC (V) Antidotes • Contrast media • Radiopharmaceuticals • Dressings

v • d • e Cough and cold preparations (R05) Expectorants Althea root • Antimony pentasulfide • Creosote • Guaiacolsulfonate • Guaifenesin • Ipecacuanha (Syrup of ipecac) • Levoverbenone • Potassium iodide • Senega • Tyloxapol Mucolytics Acetylcysteine • Ambroxol • Bromhexine • Carbocisteine • Domiodol • Dornase alfa • Eprazinone • Erdosteine • Letosteine • Mesna • Neltenexine • Sobrerol • Stepronin • Tiopronin Cough suppressants Opium alkaloids, Opioids, and derivatives Acetyldihydrocodeine • Benzylmorphine • Codeine • Dextromethorphan • Heroin • Dihydrocodeine • Dimemorfan • Droxypropine • Ethylmorphine • Hydrocodone • Hydromorphone • Isoaminile • Laudanum • Levomethadone • Levopropoxyphene • Methadone • Nicocodeine • Nicodicodeine • Normethadone • Noscapine • Pholcodine • Thebacon • Tipepidine • Zipeprol Other Benzonatate • Benproperine • Bibenzonium bromide • Butamirate • Clobutinol • Clofedanol • Cloperastine • Diphenhydramine • Dibunate • Dimethoxanate • Dropropizine • Fedrilate • Glaucine • Levodropropizine • Meprotixol • Morclofone • Nepinalone • Oxolamine • Oxeladin • Pentoxyverine • Pipazetate • Prenoxdiazine • Piperidione

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