ADVERSE DRUG REACTIONS IN DISGUISE

... A Plea For Doctors To Become Detectives! Some adverse drug reactions closely simulating natural diseases are reviewed using some of the newer examples. The main problem is that until an adverse reaction is described it may pass unnoticed. It is hard to maintain an attitude of critical suspicion sufficient to detect drug damage wherever it occurs.

There are five main reasons for adverse reactions to go unrecognised: • The· reaction may be so odd or bizarre than an often used, apparently innocent drug, is not suspected. In such cases,

withdrawing the drug rapidly reverses the effects. • The drug-induced disorder may mimic a common natural disease, as in anaesthetic-induced hepatitis. Death can be

a drug side-effect wrongly attributed to a natural cause. • There is a long delay in the appearance of the adverse reaction, as with practolol which caused lesions in 1 case

18 month5 after the drug was withdrawn. 'The delayed immune disorders are a new group of disastrous man-made diseases, and there is a need for vigilance to detect them even 5 to 8 years after a drug has been marketed. There will probably be more of them as increasing numbers of new drugs appear.'

• The drug evokes a relapse of a natural disease, or evokes a disorder in a naturally susceptible subject. Systemic lupus erythematosus is often precipitated by drugs like hydrallazine and procainamide.

• In a complex clinical situation the drug-related components may escape notice, especially in hospital where multiple disorders, polypharmacy and confused notes all contribute. Outside hospital, patient incompliance and insidious drug cumulation are problems.

How can these masquerading adverse effects be better detected? Drugs must continually be regarded as causes or evokers of symptoms not expected from the pharmacological properties of the drug. The progress of patients who are taking, or have completed, courses of drugs should be followed up. Existing methods of collating information must be used more fully. Surveys of the frequencies of a syndrome with a drug and without it are necessary, but no-one should be discouraged from suspecting, observing and reporting. 'Though national and international adverse reaction monitoring agencies exist, and have many new discoveries to their credit, most of the important new observations are still made by individual doctors.'

Vere, D.W.: Adverse Drug Reaction Bulletin 60: 208 (Oct 1976)

INPHARMA 16th October, 1976 p6