The US Food and Drug Administration and French drug-maker Sanofi-Aventis have jointly issued a warning against the careless and casual use of the firm's popular antidepressant Norpramin, stating that the medicine should be given under extreme caution to patients who have a family history of certain cardiovascular problems. The warning was issued on Wednesday.

"The new safety information states that extreme caution should be used when this drug is given to patients who have a family history of sudden death, cardiac dysrhythmias, and cardiac conduction disturbances", said the FDA.

The heart conditions that company has warned against existing in the family include "sudden death, abnormal heart rhythms and heart conduction disturbances".

The company has also warned that an overdose of Norpramin has been tested to show a higher death rate than overdoses of other antidepressants which are given in the same way.

The "warnings" and "overdosage" sections of the antidepressant's labeling are being changed to reflect these potential adverse affects.