The Food and Drug Administration (FDA) employs various methods to protect consumers from dangerous drugs and devices. The agency's black box warning directly alters pharmaceutical labeling to draw attention to significant risks and life-threatening side effects.

Also known as a "boxed warning," black box labeling is added to a drug's package insert with safety information emphasized by a dark border. Boxed warnings, the FDA's most stringent health statements, also come with a medication guide.

The warnings are intended to limit nonessential prescription of dangerous drugs, thereby mitigating harm. But black box warnings are controversial, with some doubting the effectiveness of the system in place.

Before a drug is allowed to be consumed, it will often go through scientific testing or the 510(k) premarket program. In the premarket phase, a clinical trial may or may not have found a "statistically significant" link between a drug and a side effect. The FDA may either add a boxed warning before the drug hits the market, or later in its shelf life.

Black box drugs can often cause serious injury or death. In some cases, drugs might not have a black box warning added for decades.

Generally, black box warnings are added after scientists release new studies, consumer groups send out petitions or the FDA discovers a high number of adverse event reports. Black box warnings are often based on clinical data or serious animal toxicity data.

In some cases, drugs with black box warnings are still heavily prescribed. Physicians may act as consultants for certain drugs, choosing one medication over another. Manufacturer marketing also plays a role, with commercials and print ads encouraging the public to request branded drugs from doctors.

The process of providing each patient with a comprehensive evaluation of risk and benefit is often undermined, and the black box warning is meant to act as an additional defense.

Though the black box warning is an important element of consumer protection, doctors should still discuss the associated side effects when prescribing high-risk pharmaceuticals. In truth, boxed warnings can only do so much.

While physicians have the responsibility to practice vigilant prescription patterns, it is up to manufacturers to ensure their products are safe.

Interested in drugs that carry a boxed warning? Read our guide to learn more about the blood thinner Xarelto, the permanent birth control device Essure and the antidepressant Abilify.