Drug Allergy Allergic Reaction To A Medication

Overview, Causes, & Risk Factors

An allergic reaction to a medication is an unintended immune response to themedication. Symptoms can vary from a mild rash to shortness of breath to death.It is important to understand the difference between a medication allergy anda side effect caused by a medication.

What is going on in the body?

An allergic reactionoccurswhen a person’s immune system reacts to the presence of a foreign substance. Itis an attempt by the body to get rid of the substance. In the caseof an allergic reaction to a medication, this response is harmful. It sometimescauses serious symptoms.

Side effects are adverse events that happen to a person as a resultof taking a particular medicine. Side effects that are common to medicinesinclude nausea,diarrhea, vomiting, headache, and lightheadedness. In some cases, thesewill subside even if a person continues to take the medication.

What are the causes and risks of the condition?

An allergic reaction does not usually occur the first time a person is exposedto the medication. It is only after the body learns to recognize the substancethat an immune system reaction is triggered. Almost any medicine can cause areaction. However, allergic reactions are quite rare considering the number ofover-the-counter medicines andmedications that are commonly prescribed.

Medications that are most likely to produce adverse reactions include thefollowing:

  • anticonvulsants, which are used to treat seizures
  • barbiturates, which are used to provide sedation
  • iodine, which is used in antiseptics and contrast media for some X-raytests
  • novocaine and similar anesthetics
  • penicillin and related antibiotics, such as amoxicillin
  • sulfa medications, which are also antibiotics
  • Symptoms & Signs

    What are the signs and symptoms of the condition?

    Symptoms of an allergic reaction to a medication can include the following:

  • anaphylactic shock,which is a very severe reaction that can lead to death
  • acute situational anxiety\ \generalized anxiety disorder\ \ panic disorder \ \ post-traumatic stress disorder \ \phobias\ \ obsessive compulsive disorders \ anxiety
  • hives, which aremultiple small, itchy, swollen areas on the skin
  • palpitations, whichare an unusual awareness of the heart beating within the chest
  • shortness of breath
  • skin rash
  • swelling of one or more parts of the body
  • wheezing
  • Other symptoms may also occur in some cases.

    Diagnosis & Tests

    How is the condition diagnosed?

    Diagnosis of an allergic reaction begins with a medical history and physicalexam. The healthcare provider will ask about recent medication use.

    Prevention & Expectations

    What can be done to prevent the condition?

    There is no way to prevent the development of an allergic reaction toa medication. Once a reaction has occurred, an individual should avoid thatparticular medicine. Rarely, a person will need to take a medication even ifhe or she is allergic to it. In those cases, the person can be pretreated withmedicines that prevent the allergic response. Thesemedicines include steroids, antihistamines, and epinephrine.

    What are the long-term effects of the condition?

    There are few long-term problems associated with an allergic reaction. In a fewcases, the reaction will include severe asthma or shock. However, most people recover quickly.

    What are the risks to others?

    Allergic reactions are not contagious. They pose no risk toothers.

    Treatment & Monitoring

    What are the treatments for the condition?

    Treatment includes measures to control the symptomsuntil the medicine is out of the bloodstream. Antihistamines areused to relieve rash,hives, and itching. Prednisone or othersteroidsare also used to keep more serious symptoms in check. These medicines can betaken orallyor applied to the skin.

    Asthmasymptoms can be controlled with medications to open the airways. Injections ofthe medication epinephrine are used to treat severe allergic reactions.

    What are the side effects of the treatments?

    Antihistamines can cause drowsiness. Prednisone can cause stomach problems,sleep problems, and mood swings. These side effects are generally very mild.

    Medications used to open the airways can cause shakiness and abnormal heartrate. These tend to be mild. Epinephrine can cause significant anxiety andshakiness, as well as an abnormal heart rate. This medication is oftenadministered in the provider’s office or in the emergency department.

    What happens after treatment for the condition?

    Once a person has had an allergic reaction to a medication, he or sheshould avoid that medication. Also, a person should always informhealthcare providers of any medication allergy. People with severe reactionsshould carry medical alert cards or wearID bracelets. These devices help inform providers of the allergy in emergencysituations.

    It is important not to report a side effect as anallergy. People who have had side effects from medicines may safely take themagain if they are seriously ill and need that particular medicine. Generally,medicines to which a person is allergic will be avoided except inlife-threatening diseases for which there are no other effectivetreatments.

    How is the condition monitored?

    Any new orworsening symptoms should be reported to the healthcare provider.

    Article type: xmedgeneral