Adverse Drug Reactions

Causes of Action Arising out of Adverse Drug Reactions

A study published in the Journal of the American Medical Association on April 15, 1998 measured the incidence of serious adverse drug reactions (ADRs) in hospital patients based on a meta-analysis of 39 previously conducted studies. The study included patients who were admitted to the hospital because of an ADR and patients who experienced an ADR while in the hospital, but it excluded ADRs that were the result of errors in administration. The researchers concluded that serious ADRs are frequent and the approximately 106,000 fatal ADRs annually make ADRs between the fourth and sixth leading cause of death in the United States.

Before a drug is approved for use in the United States, it undergoes extensive testing for safety and effectiveness. Even with such extensive testing, not all possible side effects can be determined prior to the time a drug is approved and marketed. Drug makers have a duty to warn of the known side effects of taking a drug, and lawsuits arising out of ADRs generally depend on whether an adequate warning was issued.

A patient who has an ADR may attempt to recover damages from the manufacturer of the drug, the prescribing physician, and/or the hospital under various theories, including strict liability, negligence, and breach of warranty.

Drugs are classified as "unavoidably unsafe products" in the Restatement 2d of Torts. Drugs are so categorized because they simply cannot be made completely safe, but testing may indicate that marketing of a drug is justified despite the existence of medical risk. Unavoidably unsafe products are not considered unreasonably dangerous or defective as long as they are properly prepared and accompanied by an appropriate warning, in which case strict liability does not result.

To prevail on a claim for strict liability based on a failure to warn, the plaintiff must generally show:

the defendant knew or should have known of a risk to the product's user;
the defendant breached its duty to warn the plaintiff of the risk;
the lack of adequate warning rendered the product unreasonably dangerous or defective; and
the defect caused the plaintiff's injuries.

To prevail on a negligence claim, the plaintiff must generally show:

a legal duty (such as the duty to warn);
a breach of that duty; and
damages proximately resulting from that breach of duty.

Breach of warranty claims are difficult in this context. To prevail on a claim for breach of the implied warranty of merchantability, a plaintiff generally has to show:

that a merchant sold the goods (i.e., the drug);
which were not merchantable (i.e., not adequately labeled) at the time of the sale;
injury and damages were suffered by the plaintiff;
the injury and damages were caused by the defective nature of the goods; and
notice of injury was provided to the seller.

As one court has stated, when a drug is accompanied by an adequate warning, a drug manufacturer cannot be held liable for breach of an implied warranty against injuries that it warned the consumer against.

Generally, if drugs are accompanied by a warning which covers all known side effects (and does not exclude any which should have been known), liability for an unforeseeable adverse reaction would not result.

04/27/98