Common cold antihistamines

Another potential benefit of UHPLC is its capability of solving the most challenging separation tasks in pharmaceutical analysis. Figure 9.4 shows a UPLC method developed to analyze pharmaceutical formulations used to treat the common cold. Cold products often contain multiple active ingredients to treat different symptoms and can contain decongestants, antihistamines, pain relievers, cough suppressants, expectorants, and numerous excipients of various polarities. The analysis of a total of 20 components was achieved within 10 min. 

Antihistamines are used to alleviate allergic conditions such as rashes and runny eyes and nose and are decongestants that are used for swelled sinuses and nasal passages during the common cold. These symptoms are caused by histamine and hence the drugs that get rid of them are antihistamines. Antihistamines are also sleep inducers. 

Agents generally referred to as antihistamines are those that antagonize the action of histamine at H3 receptors. They act in a competitive manner and are primarily used in situations such as urticaria, hay fever, and insect bites. They are available for both local and oral administration. At the time of the development of the first antihistamines in the 1940s, they were hailed as the cure for the common cold. 

Several of the older generation antihistamines are used exclusively for situations that do not involve an allergic reaction. For example, some demonstrate significant antiemetic, antimotion sickness, antiparkinsonian, antitussive, and local anesthetic actions (some Hj antagonists are more potent than procaine). They can be found in many OTC products, particularly for the relief of symptoms from the common cold and allergies, as well as by prescription. The effectiveness of the agents in the treatment of motion sickness and Parkinson s disease may be attributed to their anticholinergic actions. 

Antihistamines bind to the same active site of the enzyme that binds histamine in the cell, but they evoke a different response. An antihistamine like bFompheniramine, for example, inhibits vasodilation, so it is used to treat the symptoms of the common cold and allergies. Cimetidine (trade name Tagamet) is a histamine mimic that blocks the secretion of hydrochloric acid in the stomach, so it is used to treat individutils with ulcers. 

Hutton, N. Wilson, M.H. Mellits, D. Effectiveness of an antihistamine-decongestant combination for young children with the common cold a randomized, controlled trial. J. Pediatr. 1991, 118, 125-130. 

Clemens, C.J. Taylor, J.A. Almquist, J.R. Quinn, H.C. Mehta, A. Naylor, G.S. Is an antihistamine-decongestant combination effective in temporarily reheving symptoms of the common cold in pre school children J. Pediatr. 1997, 130, 463-466. 

Some oral products combine antihistamines with sympathomimetic decongestants and are marketed for nasal congestion associated with hayfever and the common cold. 

Carbinoxamine compound syrup (Pennex) containing 60 mg pseudoephedrine HCl, 4 mg carbinoxamine maleate, and 15 mg dextromethorphan HBr in 0.2% alcohol is indicated for relief of cough and upper respiratory systems including nasal congestion associated usually with allergy or common cold. Carbinoxamine possesses Hj antihistaminic activity with mild anticholinergic-sedative properties. Carbinoxamine, which is metabolized completely, has a serum half-life of 10 to 12 hours. 

The combination possesses antihistamine/deconges-tant/anticholinergic properties. Chorpheniramine competitively antagonizes histamine at Hj-receptor sites phenylephrine stimulates postsynaptic alpha-receptors, resulting in vasoconstriction, which reduces congestion methscopolamine competitively inhibits action of acetylcholine at muscarinic receptors. The combination is indicated for temporary relief of symptoms of allergic rhinitis, casomotor rhinitis, sinusitis, and the common cold. 

Phenylephrine tannate is an antihistamine/deconges-tant/vasopressor used in shock. Phenylephrine stimulates postsynaptic alpha receptors, resulting in vasoconstriction, which reduces nasal congestion. Chlorpheniramine and pyrilamine competitively antagonizes histamine at H,-receptor sites. They are indicated in symptomatic relief of coryza and nasal congestion associated with common cold, sinusitis, allergic rhinitis, and other upper respiratory tract conditions. 

Promethazine hydrochloride is an antihistamine/deconges-tant. Promethazine competitively antagonizes histamine at Hi-receptor sites and produces sedative as well as antiemetic effects. Phenylephrine stimulates postsynaptic alpha receptors, resulting in a rise in arterial peripheral vasoconstriction. They are indicated in temporary relief of upper respiratory tract symptoms, including nasal congestion associated with allergy or the common cold. 

The drug exerts its action by temporarily relieving rumiing nose and also sneezing related to the common cold. However, it m cause drowsiness sleepiness, just similar to most of the antihistaminics but at the same time it may also give rise to a mild stimulating action in patients and may cause insomnia when taken prior to going to bed. 

West S, Brandon B, Stolley P, RumriH R (1975) A review of antihistamines and the common cold. Pediatrics 56 100-107... 

A number of amines are vitamins. These include nicotinic acid and nicotinamide, pyridoxine (vitamin Be, see The Chemistry of... Pyridoxal Phosphate in WileyPLUS for Chapter 16), and thiamine chloride (vitamin B-, see The Chemistry of... Thiamine," in WileyPLUS for Chapter 17). Nicotine is a toxic alkaloid found in tobacco that makes smoking habit forming. Histamine, another toxic amine, is found bound to proteins in nearly all tissues of the body. Release of free histamine causes the symptoms associated with allergic reactions and the common cold. Chlorpheniramine, an antihistamine, is an ingredient of many over-the-counter cold remedies. 

Hematologic A 50-year-old woman developed an aplastic anemia 1 week after taking cefroxadine, a non-steroidal antiinflammatory drug, and an antihistamine for 3 days to treat symptoms of a common cold. She had previously had aplastic anemia after being given cefroxadine, but no other evidence was presented to link the reaction to the cephalosporin rather than one of the other drugs [12 ]. 

First-generation antihistamines provide symptomatic relief from allergies and the common cold to patients. However, their therapeutic potential is hampered by the sedation caused by their effects on histamine receptors in the brain (1-3). Second-generation antihistamine (astemizole, as an example) block peripheral HI receptors were introduced to provide comparable therapeutic benefit without the CNS side effects under manufactures recommended doses (1-4). It was reported that astemizole was found to cause arrhythmias when drug exposures became... 

Berkowitz RB, Connell JT, Dietz AJ, Greenstein SM, Tinkelman DG (1989) The effectiveness of the non-sedating antihistamine loratadine plus pseudoephedrine in the symptomatic management of the common cold. Arm Allergy 63 336-339 Bliss TV, Lomo T (1973) Long-lasting potentiation of synaptic transmission in the dentate area of the anaesthetized rabbit following stimulation of the perforant path. J Physiol 232 331-356 Brimblecombe RW (1979) Behavioral tests in acute and chronic toxicity studies. Pharmacol Ther 5 413 15... 

Release of free histamine causes the symptoms associated with allergic reactions and the common cold. Chlorpheniramine, an "antihistamine," is an ingredient of many over-the-counter cold remedies. 

The prototype antihistamine of this group is diphenhydramine. It has antimuscarinic and pronounced central sedative properties and also an antitussive effect. The mechanism of the latter is unclear, but diphenhydramine is a common ingredient of propriety preparations for the treatment of coughs and colds. It is an effective anti-emetic, especially useful for prevention and treatment of motion sickness. Because of its anticholinergic properties it is occasionally used in the treatment of mild forms of Parkinson s disease. It is also of use in the treatment of drug-induced extrapyramidal effects. Piperazine derivatives... 

Antihistamines are common ingredients over-the-counter cold remedies. 

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