Adverse reactions to drugs

An adverse reaction is any reaction to a drug that is harmful to the patient. Side effects, unwanted effects and adverse effects are all adverse reactions some are considered to be less serious than others, although the terms are used synonymously. 

Adverse drug reactions present a major clinical problem. It has been estimated that up to 5% of all admissions to hospital result from adverse reactions to drugs and in hospital up to 20% of patients experience an adverse reaction. 

Pharmacology for the Health Care Professions Christine M. Thorp 

Many adverse reactions are well known. Information about them can be found in patient information leaflets supplied with medicines, in the Monthly Index of Medical Specialties MIMS) or in the British National Formulary (BNF). However, not all patients will suffer all possible adverse reactions. Knowledge of family history can help predict who will suffer from adverse reactions. It is therefore good practice when taking a patient s history to ask about incidents of adverse reactions to drugs or allergies in the family. 

Adverse reactions to drugs can be divided into type A (augmented) and type B (bizarre). 

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Risk for Injury related to adverse reactions to drug therapy (blurring of the vision)... 

Simon RA Adverse reactions to drug additives. J Allergy Clin Immunol 1984 74 623-630. 

Adverse reactions to drugs differ in both type and incidence in the pediatric population. Because of immature metabolic pathways, infants and children may have different metabolic patterns than adults. This at least partially explains why neonates require lower theophylline serum concentrations for the treatment of neonatal apnea and why the incidence of hepatotoxi-city following acetaminophen overdose is much lower in young children than in adults [44,45]. Antibiotic adverse effects unique to the pediatric population may... 

Reprinted from J Gin Epidemiol, Vol 46, Danan C, Benichou C. Causality assessment of adverse reactions to drugs-4. A novel method based on the conclusions of international consensus meetings- Application to drug-induced liver injuries pages 1323-1330, Copyright 1993, with permission from Elsevier. 

Weiner, M. and Bernstein, I.L. (1989). Adverse Reactions to Drug Formulation Agents. Marcel Dekker, New York. 

Drug group — placebo group = number of adverse reactions to drugs... 

Stem, R.S. and Bigby M., An expanded profile of cutaneous reactions to nonsteroidal antiinflammatory dmgs reports to a specialty-based system for spontaneous reporting of adverse reactions to drugs, JAMA, 252,1433-1437,1984. 

In the United Kingdom, the present yellow card system had its origins in 1965, when Witts, who was then a member of the Committee on Safety of Drugs (the precursor to the CSM), published a method for the collection of suspected adverse reactions to drugs. 

The CSD had also started studies of adverse reactions to drugs (ADRs) by the beginning of 1964. Sir Derrick Dunlop wrote to aU the doctors (4 May 1964) and dentists (15 June 1964), inviting them... 

Every country needs an authoritative, independent, competent and reliable system for evaluating adverse reactions to drugs and vaccines - a system that is linked with and provides support for the national drug regulatory authority (NRA) and for the national ministry of health. More than 80 countries... 

In some drug reactions, several of these hypersensitivity responses may present simultaneously. Some adverse reactions to drugs may be mistakenly classified as allergic or immune when they are actually genetic deficiency states or are idiosyncratic and not mediated by immune mechanisms (eg, hemolysis due to primaquine in glucose-6-phosphate dehydrogenase deficiency, or aplastic anemia caused by chloramphenicol). 

Weiner M, Bernstein IL. Adverse Reactions to Drug Formulation Agents A Handbook of Excipients. New York Marcel Dekker, 1989 93-94. 

C.J. Davies, et al., Delayed adverse reactions to drugs used in anaesthesia. Adv. Drug React. Bull. 647-650, April 1995. 

Elderly individuals often develop adverse reactions to drugs at dosage levels well tolerated by younger persons. These reactions may be due to an age-related increase in sensitivity to drugs or impairment of detoxification (metabolism) and excretion functions. 

It is becoming increasingly evident that a number of adverse reactions to drugs are due to genetically transmitted inborn enzyme abnormalities or deficiencies. The best known example of this category is the hereditary relative deficiency of the enzyme glucose-6-phosphate-dehydrogenase (G-6-PD), which occurs in 5% to 10% of Mediterranean littoral races, blacks, Pakistanis, and Sephardic Jews. This condition renders affected individuals susceptible to acute hemolytic ane-... 

Blood dyscrasias, mostly dose independent, are among the most important allergic-type adverse reactions to drugs. Aplastic anemia is a serious but rare (presumably) idiosyncratic reaction. It has been reported in association with chloramphenicol, quinacrine, phenylbutazone, mephenytoin, gold compounds, and potassium chlorate. Hemolytic anemia, thrombocytopenia, and agranulocytosis may result from an unusual, acquired sensitivity to a variety of widely used drugs including aminopyrine, phenylbutazone, phenothiazines, propylthiouracil, diphenylhydantoin, penicillins, chloramphenicol, sulfisoxazole, and tolbutamide. 

IV. COLLECTION, EVALUATION, AND REPORTING OF ADVERSE REACTIONS TO DRUGS... 

Adverse reactions to drugs will be more instantaneous and serious, too (example penicillin allergy)... 

Voluntary reporting. Doctors, nurses and pharmacists are supplied with cards on which to record suspected adverse reaction to drugs. In the UK, this is called the Yellow Card system and the Committee on Safety of Medicines collates the results and advises the government s Medicines Control Agency. It is recommended that for ... 

It is not enough to measure the incidence of adverse reactions to drugs, their nature and their severity, though accurate data are obviously useful. It is necessary to take, or to try to take, into account which effects are avoidable (by skilled choice and use) and which are unavoidable (inherent in drug or patient). Also, different adverse effects can matter to a different degree to different people. 

Caution. About 80% of well people not taking any drugs admit on questioning to symptoms (often several) such as are commonly experienced as lesser adverse reactions to drugs. These symptoms are intensified (or diminished) by administration of a placebo. Thus, many (minor) symptoms may be wrongly attributed to drugs. 

It is convenient to classify adverse reactions to drugs under the following headings ... 

In a similar report from Turkey, adverse reactions to drugs led to withdrawal of one or more drugs in 62 of 158 patients (39%) (4). Outcomes were favorable and cultures became negative in 95% of the patients within 2 months. 

Adverse reactions are often due to the combined effects of two or more drugs used simultaneously (5). Hypersusceptibility reactions can occur even to more than one agent. The incidence of adverse reactions to drugs used in the treatment of tuberculosis is higher in elderly patients, who are more likely to have intercurrent... 

Japanese Ministry of Health and Welfare. Information on adverse reaction to drugs. Japan Med Gaz 1980 April 20 10. 

Anonymous. Mucormycosis induced by deferoxamine mesylate. Information on Adverse Reactions to Drugs. Japan Pharmaceutical Affairs Bureau, Ministry of Health and Welfare, February 1988. 

Anaphylactic shock associated with cinoxacin was reported in three patients by the Netherlands Center for Monitoring of Adverse Reactions to Drugs (97). Another 17 cases were reported to the WHO Collaborating Center for International Drug Monitoring. In some cases the reaction was observed immediately after the first dose of a repeat cycle of treatment. Anaphylactoid reactions to ciprofloxacin have been reported in patients with cystic fibrosis (98-100). 

Anonymous. Calcium hopantenate. Information on Adverse Reactions to Drugs, 1988. 

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