I. Phenergan Fact File
Phenergan was launched by Aventis.
Aventis is a part of the Sanofi-Aventis Group. The Sanofi-Aventis Group is the world's 3rd largest pharmaceutical company, ranking number 1 in Europe. Backed by a world-class R&D organization, Sanofi-Aventis is developing leading positions in seven major therapeutic areas: cardiovascular disease, thrombosis, oncology, diabetes, central nervous system, internal medicine, and vaccines.
Management of diabetes is the focus of the metabolism group within Aventis. Both the core and the late-stage pipeline products within this therapeutic area are targeting diabetes of both the types.
In the past, the predecessor companies of Aventis Pharma Limited have made major contributions to the treatment of diabetes - with the delivery of continuously improved insulin formulations since 1923 and the introduction of anti-diabetic sulfonylureas since 1950 as the standard treatment of Type 2 diabetes patients.
II. Phenergan Medication
Phenergan is a potent histaminic H1 antagonist with additional anti-emetic (Medications given to reduce nausea and vomiting) and sedative/calming properties. Phenergan (promethazine) is derived from a group of medicines called phenothiazines, however, it is also part of the family of sedating antihistamines.
Promethazine is useful for the prevention or relief of localized or less serious allergies such as hay fever or itchy rash in addition to serious allergic reactions such as anaphylaxis.
Promethazine blocks histamine receptors in an area of the brain called the vomiting centre. It also acts to block other receptors in the vomiting centre (serotonin receptors). Therefore promethazine prevents the vomiting centre from sending the nerve messages to the stomach that would normally result in vomiting. Promethazine also acts on receptors in the gut (muscarinic receptors) to decrease the amount of fluid secreted from the lining of the gut and decrease the actions of the gut muscles. This further aids the treatment or prevention of nausea and vomiting.
Promethazine is known as a sedating antihistamine as it enters the brain in significant quantities and causes drowsiness. As a result it is commonly used for the short-term treatment of sleep disturbances and to provide sedation prior to minor procedures or surgery.
Antihistamines: Information
Histamine is an important body chemical that is responsible for the congestion, sneezing, and runny nose that a patient suffers with an allergic attack or an infection.
Antihistamine drugs block the action of histamine, therefore reducing the allergy symptoms. For the best result, antihistamines should be taken before allergic symptoms get well established.
An allergy is a condition in which the body becomes unusually sensitive to some substance, such as pollen, mold spores, dust particles, certain foods, or medicines. These substances, known as allergens, cause no unusual reactions in most people. But in people who are sensitive to them, exposure to allergens causes the immune system to overreact. The main reaction is the release of a chemical called histamine from specialized cells in the body tissues. Histamine causes such familiar and annoying allergy symptoms as sneezing, itching, runny nose, and watery eyes.
As their name suggests, antihistamines block the effects of histamine, reducing allergy symptoms. When used for this purpose, they work best when taken before symptoms are too severe. Antihistamine creams and ointments may be used to temporarily relieve itching. Some antihistamines are also used to treat motion sickness, nausea, dizziness, and vomiting. And because some cause drowsiness, they may be used as sleep aids.
Histamines: Information
Histamine is an important protein involved in many allergic reactions. Allergies are caused by an immune response to a normally innocuous substance (i.e. pollen, dust) that comes in contact with lymphocytes specific for that substance, or antigen. In many cases, the lymphocyte triggered to respond is a mast cell. For this response to occur, a free-floating IgE (an immunoglobulin associated with allergic response) molecule specific to the antigen must first be attached to cell surface receptors on mast cells. Antigen binding to the mast cell-attached IgE then triggers the mast cell to respond. This response often includes the release of histamine.
The release of histamine (hist = because it's made up of histidine residues, amine = because it's a vasoactive amine) causes several allergic symptoms.
1) It contributes to an inflammatory response. 2) It causes constriction of smooth muscle.
Diagram: Histamine (Explanation for diagram: As more of the allergen enters your body, the antibodies "grab" the allergen. This triggers the basophils and mast cells to release powerful chemicals, including histamine.
Histamine can cause inflammation directly as well as indirectly. Upon release of histamine by an antigen-activated mast cell, permeability of vessels near the site is increased. Thus, blood fluids (including leukocytes, which participate in immune responses) enter the area causing swelling. This is accomplished due to histamine's ability to induce phosphorylation of an intercellular adhesion protein (called (VE)-cadherin) found on vascular endothelial cells. That is why histamine is known as being vasoactive. Gaps between the cells in vascular tissue are created by this phosphorylation, allowing blood fluids to seep out into extracellular space.
Indirectly, histamine contributes to inflammation by affecting the functions of other leukocytes in the area. It has been suggested by researchers that histamine release triggers the release of cytokines and inflammatory mediator by some neighboring leukocytes. These chemicals in turn increase the inflammatory response.
Histamine's second type of allergic response is one of the major causes for asthma. In response to an allergen (a substance that triggers an allergic reaction), histamine, along with other chemicals, causes the contraction of smooth muscle. Consequently, the muscles surrounding the airways constrict causing shortness of breath and possibly complete trachial-closure, an obviously life-threatening condition. If the effects of histamine during an allergic reaction are inhibited, the life of an allergic person can be eased (in the case of inflammation) or even saved by preventing or shortening asthma attacks. Thankfully, many effective drugs have been developed to hinder histamine's allergic response activities.
Side effects Of antihistamines
Common side effects of antihistamines include drowsiness, dizziness, poor coordination, restlessness, excitability, nervousness, and upset stomach. These problems usually go away as the body adjusts to the drug and do not require medical treatment. Less common side effects, such as dry mouth, nose, and eyes, irritability, difficulty urinating, and blurred vision, also may occur and do not need medical attention unless they do not go away or they interfere with normal activities.
If any of the following side effects occur, check with the physician who prescribed the medicine as soon as possible:
- Rapid, irregular, pounding, or fluttering heartbeat
- Convulsions
- Sweating
- Vomiting
- Fever
- Chills
- Fainting
- Breathing problems
- Hallucinations
- Unusual bleeding or bruising
- Low blood pressure
- Unusual sensitivity to light
- Uncontrolled movements
Alternate Uses Of Antihistamines
- Motion sickness
- Vertigo (severe dizziness)
- Nausea and vomiting
- Stiffness and tremors in patients with Parkinson's disease (diphenhydramine)
- Cough due to colds or hay fever (the syrup form of diphenhydramine)
- Insomnia
- Pre-operative sedation
- With narcotic analgesics for severe pain
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III. Useful links
Government http://www.cdc.gov/
http://www.fda.gov/
http://www.fda.gov/cder/ogd/
http://www.nih.gov/
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
http://www.health.gov.on.ca/
National Library of Medicine
World Health Organization
Health Sites
http://www.mayoclinic.com/index.cfm
MedicineNet.com
Drugdigest.org
Healthsquare.com
About.com Health section
www.amaryl.com
http://www.netdoctor.co.uk/medicines/100002055.html
http://www.entnet.org/healthinfo/allergies/antihistamines.cfm
http://www.bio.davidson.edu/courses/Immunology/Students/spring2000/lamar/mfirp.htm
Pharmacy sites
http://www.roche.com/home/company/com_hist.htm
http://www.healthdigest.org/Bactrim-DS(Oral)_2006_PRO.php
http://www.hsforum.com/stories/storyReader$1509
http://www.hsforum.com/stories/storyReader$1504
http://www.people.vcu.edu/~urdesai/atc.htm#Process%20of%20clotting
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