Download Drugs for Inflammation, Fever, and Allergies Expanded Key Concepts

Drugs for Inflammation, Fever, and Allergies
Expanded Key Concepts
31.1 Inflammation is a natural, non- specific response that limits the spread of invading
microorganisms or injury. Acute inflammation occurs over several days whereas chronic
inflammation may continue for months or years.
Inflammation is a non-specific response designed to rid the body of invading organisms that may
occur in response to a large number of different stimuli. This includes physical injury, exposure to
toxic chemicals, extreme heat, invading microorganisms or death of cells. Acute inflammation
occurs quickly and may require aggressive pharmacotherapy.
31.2 Histamine is a key chemical mediator in inflammation. Release of histamine produces
vasodilation that allows capillaries to become leaky, thus causing tissue swelling.
Chemical mediators initiate inflammation. One of the most important mediators is histamine.
Histamine dilates nearby blood vessels, causing capillaries to become more permeable. It allows
complement proteins and phagocytes to enter the area to neutralize foreign agents. Extremely
rapid release of histamine throughout the body can cause anaphylaxis.
31.3 Histamine can produce its effects by interacting with two different receptors.
The classic antihistamines used for allergies block H1 histamine receptors in vascular smooth
muscle, in the bronchi, and on sensory nerves. The H2 receptor antagonists are used to treat
peptic ulcers.
H1 receptor antagonists are used to treat allergies and inflammation whereas H2 receptor
antagonists are used to treat peptic ulcers.
31.4 Nonsteroidal anti-inflammatory drugs (NSAIDS) are the primary drugs for the treatment of
simple inflammation. Newer, selective COX-2 inhibitors cause less GI distress.
NSAIDs are drugs that inhibit the enzyme, cyclooxygenase. Nonselective cyclooxygenase
inhibitors, including aspirin, are very effective at reducing inflammation and pain, but cause
significant GI side effects in some patients. The newer, selective COX-2 inhibitors cause less GI
disturbance.
31.5 Systemic glucocorticoids are effective in treating acute or severe inflammation. As overtreatment with systemic glucocorticoids can cause a serious condition called Cushing's
syndrome, therapy for inflammation is generally short-term.
Glucocorticoids have the ability to suppress histamine release and inhibit the synthesis of
prostaglandins by cyclooxygenase-2. In addition, they can inhibit the immune system by
suppressing certain functions of phagocytes and lymphocytes. Glucocorticoids are the most
efficacious medications available for the treatment of severe inflammatory disorders.
31.6 NSAIDs and acetaminophen are the primary agents used to treat fever.
Prolonged, high fever is an indication for drug therapy. Aspirin and other NSAIDs are the drugs of
choice for adults. Acetaminophen is the drug of choice for children.
31.7 Allergic rhinitis is a disorder characterized by sneezing, watery eyes, and nasal congestion.
Allergic rhinitis, also known as hay fever, is a chronic allergy triggered by a wide variety of
antigens. The release of chemicals mediating the immune response can result in seasonal
symptoms for some patients and chronic, continuous symptoms for others.
31.8 Antihistamines, or H1 receptor antagonists, can provide relief from the symptoms of allergic
rhinitis. Newer drugs in this class are non- sedating and offer the advantage of once-a-day
dosage.
The H1 receptor antagonists, commonly known as antihistamines, are used to treat allergies and
inflammation. Antihistamines are most effective when taken prophylactically to prevent allergic
symptoms. They are also among the few drugs available to treat vertigo, a form of dizziness that
causes significant nausea.
31.9 Intranasal glucocorticoids have become the drugs of choice for treating allergic rhinitis due
to their high efficacy and wide margin of safety.
Glucocorticoids may be applied directly to the nasal mucosa to prevent symptoms of allergic
rhinitis. They have begun to replace antihistamines as the drugs of choice for the treatment of
chronic allergic rhinitis. When used by inhalation, intranasal glucocorticoids do not produce the
serious adverse effects that have been observed when they are given orally.
31.10 Oral and intranasal sympathomimetics are used to alleviate nasal congestion due to
allergic rhinitis and the common cold. Intranasal medications are more efficacious, but can only
be used for 3 to 5 days due to rebound congestion.
Sympathomimetics with alpha adrenergic activity are effective at relieving nasal congestion
associated with allergic rhinitis when given by either oral or intranasal routes. Though effective
with a rapid onset of action, use of the intranasal preparations is usually limited to 3-5 days due to
the potential for rebound congestion.
31.11 Anaphylaxis is a serious and often fatal allergic response that is treated with a large
number of different drugs. These include: sympathomimetics, antihistamines, and glucocorticoids.
When the body mounts a hyper-response to an antigen, anaphylactic shock may result.
Epinephrine is a drug of choice for immediately reversing the cardiovascular symptoms. Other
vasoconstrictors, antihistamines, and corticosteroids also serve a role in treating this form of
shock.