Type A adverse reactions

The adverse, toxic effects of drugs can be divided into one of two t5rpes, A and B. Type A adverse reactions are due to the pharmacological (therapeutic) effect of the drug and are therefore usually predictable and related to the dose. They are usually exaggerated therapeutic effects. Type B are unexpected, idiosyncratic effects. 

These adverse drug reactions are generally dose-related and most can be predicted. They can be caused by an exaggeration of a drug s intended pharmacological effect or by an unwanted action or side effect. Type A adverse reactions are most likely to occur with drugs that have a steep dose-response curve (see Figure 3.1) and/or small therapeutic ratio (TR). 

A summary of type A adverse reactions is given in Table 3.2. 

Adverse reactions can occur by a variety of mechanisms and some of them are well known. Type A adverse reactions are dose-related and can be predicted to occur through accidental overdose, individual differences due to age, disease or genetics or drug-drug interactions. 

ADRs are often classified into two major sorts so called Type A and Type B reactions. Type A adverse reactions are those which may be anticipated from the nature of the treatment (perhaps due to knowledge of class effects or mechanisms of action) and are dose-dependent. Type B adverse reactions are those which are unpredictable from background knowledge. They are usually a form of hypersensitivity or immunological reaction peculiar to the individual and may occur even with very small doses. They may be caused by the drug itself or by metabolites. Type B reactions are usually rarer and more serious than type A reactions. 

Three years after introduction of aspirin into therapy, Hirschberg in Poznan, now in Poland, described the first case of a transient, acute angioedema/urticaria, occurring shortly after ingestion of aspirin. Reports of anaphylactic reactions to aspirin soon followed. The other major type of adverse reaction, acute bronchospasm, was described in the second decade of the 20th century. In 1920, Van der Veer reported the first death due to aspirin. The association of aspirin sensitivity, asthma and nasal polyps was first recorded by Widal in 1922. This clinical entity, later named the aspirin triad was popularized in 1968 by Samter and Beers [3], who presented a... 

The degree to which genetic factors contribute to interindividual variability in myopathy risk has been an active area of investigation for more than a decade. There are two types of adverse reactions ... 

A type A adverse drug reaction is a possibility if a patient is given a higher than recommended dose for any particular route of administration due to practitioner error. In order to avoid this it is good clinical practice for drug dosages to be checked by another member of staff prior to administration. Where this is not possible, or impracticable, extreme care must be taken to ensure that a patient receives the right dose of the correct medicine by the route intended. 

Dose-related (type A) adverse drug reactions are predictable and arc caused by an cxce.ss of the drug s wanted pharmacological effect (e.g. hypoglycacmia with insulin, bleeding with heparin) or sometimes... 

Kava use has been associated with several other types of adverse reactions. Persistent Parkinsonism was reported in a 54-year-old woman with a family history of essential tremors after 10 days of kava use (65 mg/day) symptoms abated as kava was discontinued and medical treatment was started (Meseguer et al. 2002). 

Author s note Sex hormones, particularly estrogens and progestogens, can be used separately or in combination, and for various purposes. It is often not possible to determine to which compound or combination a particular adverse reaction can be attributed information on particular types of adverse reactions may therefore need to be sought under a series of differing headings. 

Medical in-patients who were given chlorpromazine were observed in a number of hospitals. Among 556 consecutively observed patients adverse reactions to the drug were observed in 68 (12.2%) in 7 of these patients the reaction to the drug was considered to be life-threatening. The types of adverse reaction observed are shown in Table 1. 

Transfusion-induced autoimmune disease has been a significant complication in the treatment of patients who require multiple platelet transfusions. Platelets and lymphocytes carry their own blood group system, ie, the human leukocyte antigen (HLA) system, and it can be difficult to find an HLA matched donor. A mismatched platelet transfusion does not induce immediate adverse reactions, but may cause the patient to become refractory to the HLA type of the transfused platelets. The next time platelets with an HLA type similar to that of the transfused platelets are transfused, they are rejected by the patient and thus have no clinical efficacy. Exposure to platelets originating from different donors is minimized by the use of apheresis platelets. One transfusable dose (unit) of apheresis platelets contains 3-5 x 10 platelets. An equal dose of platelets from whole blood donation requires platelets from six to eight units of whole blood. Furthermore, platelets can be donated every 10 days, versus 10 weeks for whole blood donations. 

In order to achieve the desired fiber properties, the two monomers were copolymerized so the final product was a block copolymer of the ABA type, where A was pure polyglycoHde and B, a random copolymer of mostly poly (trimethylene carbonate). The selected composition was about 30—40% poly (trimethylene carbonate). This suture reportedly has exceUent flexibiHty and superior in vivo tensile strength retention compared to polyglycoHde. It has been absorbed without adverse reaction ia about seven months (43). MetaboHsm studies show that the route of excretion for the trimethylene carbonate moiety is somewhat different from the glycolate moiety. Most of the glycolate is excreted by urine whereas most of the carbonate is excreted by expired CO2 and uriae. 

In addition to the CIR process the cosmetic industry has instituted a second, important, self-regulatory procedure the voluntary reporting of adverse reactions, which is intended to provide data on the type and incidence of adverse reactions noted by consumers or by their medical advisors. This reporting procedure creates early awareness of problems handled outside hospital emergency facilities or centers for acute poisoning. 

Administration of trimethadione (Tridione) may result in hematologic changes, such as pancytopenia (decrease in all the cellular components of the blood), leukopenia, aplastic anemia, and thrombocytopenia Also reported are various types of skin rashes, diplopia (double vision), vomiting, changes in blood pressure, CNS depression, photosensitivity, and fatal nephrosis. Because these dm have been associated with serious adverse reactions and fetal malformations, they should be used only when other less toxic dm are not effective in controlling seizures. The oxazolidinediones may precipitate a tonic-clonic seizure... 

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