Hypersensitivity reactions type 11 drug

Hypersensitivity reactions with P-lactam antibiotics, especially penicillin, may encompass any of the type I through IV Gell-Coombs classifications. The most common reactions are maculopapular and urticarial eruptions.7 While rare (less than 0.05%), anaphylaxis to penicillins causes the greatest concern because they are responsible for the majority of drug-induced anaphylaxis deaths in patients, accounting for 75% of all ana-i phylaxis cases in the United States.5,8 The treatment of ana-I phylaxis is given in Table 51-2.9... 

Vancomycin is effective and is the drug of choice for the patient with a history of immediate-type hypersensitivity reaction to penicillin. When vancomycin is used, the addition of gentamicin is not recommended. 

Type IV Delayed-type Hypersensitivity (DTH). Delayed-type hypersensitivity reactions are T-cell mediated with no involvement of antibodies. However, these reactions are controlled through accessory cells, suppressor T cells, and monokine-secreting macrophages, which regulate the proliferation and differentiation of T cells. The most frequent form of DTH manifests itself as contact dermatitis. The drug or metabolite binds to a protein in the skin or the Langerhans cell membrane... 

Types II and III Hypersensitivity. No simple animal models are currently available to assess Type II (antibody-mediated cytotoxicity) hypersensitivity reactions. IgE antibodies and immune complexes in the sera of exposed animals can be assayed using ELISA or RIA techniques that require the use of specific antibodies to the drug. 

Growth factor potential The possibility that epoetin alfa can act as a growth factor for any tumor type, particularly myeloid malignancies, cannot be excluded. Hypersensitivity reactions Skin rashes and urticaria are rare, mild, and transient. If an anaphylactoid reaction occurs, immediately discontinue the drug and initiate appropriate therapy. Refer to Management of Acute Hypersensitivity Reactions. Fertility Impairment In female rats treated IV with epoetin alfa, there was a trend for slightly increased fetal wastage at doses of 100 and 500 units/kg. 

Pharmacology Lodoxamide is a mast cell stabilizer that inhibits the in vivo Type I immediate hypersensitivity reaction. Although lodoxamide s precise mechanism of action is unknown, the drug may prevent calcium influx into mast cells upon antigen stimulation. 

Roychowdhury, S. and Svensson, C.K. (2005) Mechanisms of drug-induced delayed-type hypersensitivity reactions in the skin. AAPS Journal,... 

Type B effects are not related to the pharmacological properties of these drugs. Serious side effects may occur. Allergic skin and liver reactions to aspirin and paracetamol have been reported with risk of fibrosis, particularly in the retroperitoneal region for methysergide and hypersensitivity reactions with NSAID and pure analgesics. 

These are adverse reactions resembling the effects of histamine liberation Chistaminoid ) and unrelated to the mode of action of the drug itself. Histamine release appears to be the main factor involved in all types of hypersensitivity reactions and its release explains most of the manifestations. The term anaphylactoid may equally be used to describe these reactions, meaning simply that they resemble anaphylactic reactions, while the term anaphylactic is used specifically for immune-mediated phenomena involving previous sensitisation of the patient. It is often difficult to determine the true nature and cause of the reaction. 

Most anaphylactoid reactions are due to a direct or chemical release of histamine, and other mediators, from mast cells and basophils. Immune-mediated hypersensitivity reactions have been classified as types I-IV. Type I, involving IgE or IgG antibodies, is the main mechanism involved in most anaphylactic or immediate hypersensitivity reactions to anaesthetic drugs. Type II, also known as antibody-dependent hypersensitivity or cytotoxic reactions are, for example, responsible for ABO-incompatible blood transfusion reactions. Type III, immune complex reactions, include classic serum sickness. Type IV, cellular responses mediated by sensitised lymphocytes, may account for as much as 80% of allergic reactions to local anaesthetic. 

A severe type I hypersensitivity reaction such as systemic anaphylaxis (eg, from insect envenomation, ingestion of certain foods, or drug hypersensitivity) requires immediate medical intervention. 

Immunologic reactions to drugs resulting in serum sickness are more common than immediate anaphylactic responses, but type II and type III hypersensitivities often overlap. The clinical features of serum sickness include urticarial and erythematous skin eruptions, arthralgia or arthritis, lymphadenopathy, glomerulonephritis, peripheral edema, and fever. The reactions generally last... 

Oxcarbazepine is closely related to carbamazepine and useful in the same seizure types, but it may have an improved toxicity profile. Oxcarbazepine has a half-life of only 1-2 hours. Its activity, therefore, resides almost exclusively in the 10-hydroxy metabolite, to which it is rapidly converted and which has a half-life similar to that of carbamazepine, ie, 8-12 hours. The drug is mostly excreted as the glucuronide of the 10-hydroxy metabolite. Oxcarbazepine is less potent than carbamazepine, both in animal models of epilepsy and in epileptic patients clinical doses of oxcarbazepine may need to be 50% higher than those of carbamazepine to obtain equivalent seizure control. Some studies report fewer hypersensitivity reactions to oxcarbazepine, and cross-reactivity with carbamazepine does not always occur. Furthermore, the drug appears to induce hepatic enzymes to a lesser extent than carbamazepine, minimizing drug interactions. Those adverse effects—such as hyponatremia—that do occur with oxcarbazepine are similar in character to reactions reported with carbamazepine. 

Q4 Antihistamines are effective in managing many of the troublesome symptoms of allergic rhinitis. Histamine is a neurotransmitter and a mediator of type 1 hypersensitivity reactions, such as urticaria and hay fever. There are several types of histamine receptors and these allergic conditions can be treated with Hi receptor antagonists, such as promethazine, chlorphenamine and fexofenadine. First-generation antihistamines, such as promethazine, cause sedation and possess side effects associated with actions on muscarinic receptors. Fexofenadine is a newer drug with a longer duration of action, which does not sedate the patient. 

The major adverse reactions to the penicillins are hypersensitivity responses. Manifestations of hypersensitivity inclnde nrticaria, angioedema, and anaphylaxis (type 1 reaction) hemolytic anemia (type 11 reaction) interstitial nephritis, vascnlitis, and serum sickness (type 111 reaction) and contact dermatitis or Stevens-Johnson syndrome (type IV reaction). A maculopapular rash occnrs late in the treatment course of 2% to 3% of patients receiving a penicillin drug. Once a patient has had a hypersensitivity response to a penicillin, it is probable, bnt not certain, that a reaction will occur with exposure to the same penicillin or to any other penicillin. Intradermal skin tests can predict whether a patient is at risk for developing a hypersensitivity reaction to the penicillins. If the resnlts are positive, penicillins should generally be avoided. 

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