Painful Design

Henry Petroski. American Scientist. Volume 93, Issue 2. Mar/Apr 2005.

Medicine used to come in simple, easy-to-open packages-at least in principle. In the 19th century, a bottle of elixir might be stoppered by a tapered cork. A properly fitted cork projected above the bottle opening, thus exposing a gripping surface. Getting to the contents usually involved a relatively easy and uncomplicated motion. In time, the cork was replaced by the screw-on top (with a cork insert), which was considered an improvement in packaging because it provided a more secure seal. However, opening a screw-capped bottle could require a more complicated multistaged twisting motion. As with all technological change, the improvement came at a cost.

Unfortunately, there was a more insidious aspect of pharmaceutical packaging that was not addressed by the change in the means of closure. Drugs, which can be beneficial when taken in the proper dosage, can be deadly when taken inappropriately. Children in particular can be put at risk by ingesting an adult dose or more of a powerful medicine. Potentially harmful drugs are commonly kept in an unlocked medicine chest, and parents long implicitly relied on the cabinet’s high position above the bathroom washbasin for keeping the potential poisons out of reach. But young children do learn to climb on stools and sinks, and do get into things not intended for them.

Caution: Children at Play

In the 1960s, seven deaths per one million children in the U.S. annually were traced to an accidental overdose of acetylsalicylic acid (aspirin). At the end of the decade, more than 50 children under five years old were dying of aspirin overdose each year, and annual deaths involving drugs and non-drug household products of all kinds exceeded 200. Such statistics led to the passage of the Poison Prevention Packaging Act of 1970, which among other things mandated that by 1972 aspirin, prescription drugs and hazardous household products be contained in child-resistant packaging.

Compliance with this legislation led to the current bewildering variety of medicine-bottle caps that cannot be popped open casually. Some require that a pair of arrows be aligned; others cannot be opened unless the top is pushed down or squeezed in while being twisted. Regardless of its operating principle, a bottle/cap combination qualified as complying with the law only by passing a specified testing protocol: It had to foil a significant percentage of young children, while at the same time not be impossible to crack for an inordinate number of adults.

Over about two decades, the “child-proof” packages were credited with reducing poisoning fatalities by half. However, there were still about 25 child deaths per year, and about 30,000 children ended up in emergency rooms after swallowing prescription drugs. A large number of the poisonings were attributed to the behavior of older adults, especially grandparents. Some found the child-resistant caps so difficult to operate that, once removed, they were left off, or the medicine was transferred to a more easily accessible container. Many visiting or live-in grandchildren thus had virtually unrestricted access to potent medicines. In the late 1980s, 17 percent of accidental poisonings of young children were being attributed to their grandparents’ prescription drugs. Though the rate of fatalities declined in the mid-1990s, poisoning incidents increased to almost half a million annually. Staff members at poison centers began calling dinnertime, when, adults were distracted with food preparation, “the arsenic hour” for unsupervised children.

A Design Riddle

The problem of preventing children from gaining access to dangerous materials was nothing new. In his 1962 patent for “receptacles with positive locking closures,” Elbert Thornton observed that in spite of “the considerable volume of prior art on the subject, and the fact that much time has been devoted to finding a satisfactory solution to the problem, no suggestion has heretofore been presented which is completely practical.” His invention, employing a “wedge means or wedging abutment to prevent removal of the closure from the container unless the wedge means or wedging abutment is operated,” was one of a great number to use such an approach. Like so many previous and subsequent ones, Thornton’s solution concentrated on securing the top on the container rather than on facilitating its removal.

One inventor who did not ignore the importance of opening the container was Gerhardt Uhlig, whose 1975 patent for a “safety closure container” employed “registering abutments and projections” to secure the top. According to Uhlig, his solution “embodies a safety lock feature which frustrates opening by a child but is relatively easily opened by a person exercising a purposeful, intelligent, cooperative, dextrous, mind-hand opening effort.” However, even if they did have the wherewithal to do so, not all elderly arthritics seeking pain relief were likely to have the patience to exercise such an effort. Furthermore, many in this category had such advanced arthritis that their hands simply did not have the requisite strength or flexibility.

In 1995, the Consumer Product Safety Commission, which oversees the testing protocol for child-resistant packaging, enacted a rule change. Instead of using 18- to 45-year-olds to test child-resistant packaging, the new protocol required a more appropriate test panel consisting of 50- to 70-year-olds. After all, people in this age range are more likely to be stricken with ailments such as arthritis, which not only requires them to take strong prescription drugs but also impairs movement and lessens strength in their hands. Under the new regulations, which took effect in 1998, 90 percent of the senior test panelists have to be able-on the first try-to open a candidate container within five minutes and to reclose it within one minute. The container must also be tested on a panel of children aged 42 months to 51 months. They are handed the bottle, shown how to open it and then left alone with it. If more than 20 percent of the kids succeed in opening the package on their own within 10 minutes, even if using their teeth, it fails to qualify as child-resistant. According to one evaluation with the new protocol, “an approved closure requires cognitive skills instead of physical strength.”


Whatever the solution requirements, the problem of designing an effective child-resistant drug container that is at the same time not a challenge for the elderly to open has been called “one of the biggest riddles in packaging” and one that “has taxed the ingenuity of engineers” for decades. It is, in fact, a paradigmatic problem in engineering design. Not only does it involve the fundamentally competing objectives of being child-resistant and adult-friendly, but it also involves considerable ancillary constraints relating to economics, aesthetics and manufacturability, as well as further regulation by the Food and Drug Administration. Among the reasons given for the lack of a revolutionary solution to the problem is that “a major change in the configuration of a drug closure could require use of new material, and that would send the closure through the PDA’s time-consuming package qualification process,” which “has to do not with ease of use or child resistance, but rather with the possible interaction between product and container.”

Although there may appear to have been relatively little variation or evolution in the packages of pills we have brought home from the pharmacy over the past three decades, patents for childresistant containers and safety caps have in fact multiplied since the mid-1970s. One bottle/cap combination that operates in a distinctly different manner was patented in 1990 by Del Thornock, a principal in the California firm Design Partners, and five other inventors, four of whom resided in and around Cincinnati, Ohio, the headquarters of Procter & Gamble, to whom the patent was assigned. As described in this patent, the object of the invention was “to provide an improved package, which is resistant to opening by the majority of children coming into contact with the package, but which at the same time can readily be removed by adults who may have impaired manual dexterity in their fingers due to conditions such as advancing age, arthritis, etc.” Thornock and his colleagues had attacked the big riddle and come up with a novel answer.

Unlike most child-resistant bottle/cap combinations, in which the hand holding the bottle is passive while the other manipulates the cap into submission, the Thornock package requires the active participation of both hands to be opened. Instead of the cap being pushed down or squeezed while also being twisted, “pushtabs” on the side of the bottle proper must be pushed in with the fingers of one hand before the cap can be unscrewed by the other. In order to give the pushtab assembly a space into which to be depressed, the plastic bottle itself is manufactured in two parts: a solid-walled bottle proper, and a collar containing the tabs that snaps onto it. When assembled, the collar gives the bottle its characteristic slope-shouldered shape, which itself is covered by a design patent. The overall design of the package is sleek, with smooth soft curves marred only by the sharply defined “pushtabs,” assembly seam and straight edge of the beveled cap.

At the same time that this new package design was being developed, Procter & Gamble was negotiating with the Syntex Corporation of PaIo Alto, California, to market an over-the-counter version of the prescription arthritis drug Naprosyn. Syntex’s patent on Naprosyn was nearing expiration, and so sales were expected to drop off as generic versions became available. In order to capitalize on the popularity and good reputation that Naprosyn had developed, its principal ingredient, naproxen, was incorporated-as naproxen sodium-into a new over-the-counter pain reliever to be sold under the new brand name Aleve, beginning in 1994. It was to be the first such drug sold in a child-resistant package that was patented expressly for the purpose.

At the time, the market in over-the-counter pain relievers exceeded $2 billion annually, and it was dominated by such well-known brands as Advil (a form of ibuprofen) and Tylenol (whose active ingredient is acetaminophen). A fierce battle of the brands was anticipated, and Procter & Gamble was willing to stake $100 million in marketing and promotion costs to get in on the game. It was expected to take years to make a profit on the venture, but thanks to an extremely successful campaign, sales of Aleve took off and grossed $150 million in the first year. It is considered one of the most successful introductions of an over-the-counter drug in marketing history.

In its original arrangement with Syntex, Procter & Gamble was to market Aleve only in the United States, but the company soon wanted to take the drug worldwide. In the meantime, however, Syntex had been acquired by the Swiss pharmaceutical company Roche Holding, which balked at a wider distribution of Aleve. Consequently, Procter & Gamble divested itself of its share. In 2004, Roche Consumer Health was acquired by Bayer, which now distributes Aleve.

Design Degradation

Regardless of who was the drug’s distributor, the patented Aleve bottle that had promised so much to so many had come in for criticism. Since it took two good hands to open, many older users could not easily manage to do so. In response to their complaints, a new “arthritis cap” for certain size bottles of Aleve was introduced in 2001. This cap, which has prominently raised ribs around its edge, does not have the original cap’s interior lugs that are engaged by the ends of the pushtabs. As a result, the arthritis cap can be unscrewed without squeezing in the bottle tabs. The Consumer Product Safety Commission allows manufacturers to offer such a non-secure package as long as the package is clearly labeled as being “not child-resistant.”

A bottle of Aleve with the arthritis cap provides an interesting study in ad hoc redesign in response to consumer demand. Rather than topping off a completely redesigned bottle, the new cap was simply put on bottles of the old design. No doubt this saved time and money in packaging design, production, inventory and assembly-line operations. Unfortunately, as is so often the case, such a quick fix overlooks some of the niceties of design and introduces inconsistencies in the total package. The “easy open arthritis cap” sits atop a bottle whose pushtabs are nonfunctional. These vestiges of a once-integral design were now design blemishes and an ironic reminder of a failure. Furthermore, the box that trumpeted an “ease-of-use commendation for packaging” from the Arthritis Foundation also contained the warning, “Do not use if carton is open or if foil seal imprinted with ‘Safety squEASE®’ on bottle opening is missing or broken,” which is a reference to the patented bottle-and-cap combination that no longer applies. No doubt the manufacturer and distributor welcomed the minimal investment in redesign that resulted in a package that could be marketed to otherwise disaffected and lost customers. However, this was done at the expense of design integrity and produced an artifactual system that was full of inconsistencies and thus that diminished the overall design environment in which we all live and consume.

Aleve has also provided other examples of design degradation. Once, I bought a 100-caplet bottle of Aleve that came in a carton that I soon discovered was about 30 percent longer than the bottle was high. This resulted in a noisy package, with the bottle shuttling back and forth between the ends of the carton when it was shook. The deep thud of the bottle banging against the carton ends was accompanied by the higher-pitched noise of the loose pills rattling about inside. According to Aleve’s Web site, the absence of cotton in the bottle makes it easier to access the contents. Evidently, the company’s studies reportedly found cotton to be unnecessary for protecting the pills from damage during snipping. It may also be the case that not inserting cotton reduces the time and cost of packaging. And using one size carton for different size bottles must also produce savings for the manufacturer.

Many of these design inconsistencies are corrected in another package of Aleve that I bought more recently. This shoppers’-club-sized carton of 250 pills bears none of the patent numbers found on older boxes, which is appropriate since the one-piece bottle does not have any pushtabs. Indeed, its cap is of an entirely different design but one that is totally familiar to users of household products of all kinds. This cap, which is of the “push down & turn” variety, can be opened easily with the palm of one hand, and the instructions imprinted on its top are hardly necessary. Furthermore, the carton bears in simple if contorted English the unregistered warning, “Use only if seal under bottle cap with white ‘sealed for your protection’ print is intact.” There is no mention of “Safety squEASE®.”

Tamper Resistance

Such warnings are, of course, a result of the drug-tampering incidents of 1982 in which seven people in the Chicago area died after ingesting capsules of Extra-Strength Tylenol laced with cyanide. Child-resistant packaging did not mean terrorist-proof packaging. Someone, who has yet to be identified, evidently acquired packages of Tylenol, opened the capsules and replaced the medicine with the poison, reassembled the capsules, put them back in the bottle, closed up the carton and surreptitiously put them back onto store shelves. It was a time when consumers were unsuspecting of such unconscionable behavior, and the poisonings shocked the world.

When Tylenol’s maker, Johnson & Johnson subsidiary McNeil Consumer Products, grasped what had happened, 31 million bottles of Tylenol were quickly recalled and newspaper ads were taken out warning people not to take the drug. Television coverage further spread the word, and it was not clear that Tylenol, which had had 37 percent of the market for over-the-counter painkillers, would ever recover from the episode. However, within six weeks of the poisonings, the company announced that Tylenol would be reintroduced in tamper-resistant packaging, which was soon on store shelves. The new packaging had three levels of protection: The carton itself was sealed, the cap was sealed to the bottle with a plastic neck wrap, and the bottle opening was covered with an imprinted foil inner seal.

Within a year, the Food & Drug Administration promulgated stricter regulations to avoid product tampering. Today, the protection of supermarket and drugstore items by sealed cartons and plastic neck bands has become familiar, if not expected, and consumers have become accustomed to dealing with the sometimes tenacious wrappings. Another consequence of the Tylenol incidents was the replacement of the once-common drug capsule-whose oblong shape and smooth surface made it easy to take but also easy to open and close without detection-with such portmanteau-designated alternatives as caplets (for capsule-shaped tablets) and gelcaps (for gelatin-coated capsule-shaped tablets).

Regardless of its form, Tylenol must, of course, also come in a child-resistant package. Its familiar model is of the “line-up arrows/push-off” type, which some arthritics have found challenging, to say the least. The relatively small lug on the cap that must be aligned with the difficult-to-see arrow on the bottle tests eyesight as well as finger strength. It was thus not surprising when Tylenol Arthritis Pain pills began to be advertised to be “the only pain reliever with a cap that is both easy to use and child resistant.” The new cap still requires arrows to be lined up, but it is topped with a large vertical “wing” pierced by a hole into which a pen or pencil can be inserted to provide leverage.

More recently, still another new cap has been introduced for Tylenol Arthritis Pain, but this one is “not intended for households with small children.” Advertised as “the easiest opening arthritis cap” available, the large blue closure has gripping knobs so large that they make it look more like a spur gear or a studded tire than a bottle cap. And it comes with a moneyback guarantee that the bottle is “easier to open than Advil or Aleve.” These new caps for Tylenol Arthritis Pain bottles certainly provide an improvement in function but at the expense of elegance in design.

To many an engineer or inventor, design elegance involves not so much the niceties of appearance as the often-overlooked characteristics of manufacturing. In his patent for a “Child-resistant one-piece container and one-piece closure assembly,” James Herr criticizes the Aleve design for not having a one-piece bottle. After pointing out that “manual dexterity in both hands is required to remove the closure,” he continues, “These packages are also difficult to manufacture because they use a complicated two-piece container assembly” in addition to the cap. Herr contends that his invention is an improvement because it incorporates the pushtabs into the cap of the bottle, which can thus be opened with only one good hand. Advil now comes in such a bottle.

Another aspect of package design that is usually beyond the consideration of engineers and inventors is communicating to the user how to operate a closure. The Advil top is a model of communication. On the face of the cap is a graphic depiction of a thumb and index finger squeezing the pushtabs inward, in the direction of a pair of arrows. A second pair of curved arrows indicates the direction in which the cap must be turned. No words are necessary. In contrast, I find the directions imprinted on the traditional Aleve bottle cap inconsistent and potentially confusing. Here, a pair of arrowheads point outward toward the tabs, not in the direction in which they should be pushed. That information is provided by the legend, “squeeze tabs and turn cap.” In the center of the cap is a pair of stylized arrows curving around in a counter-clockwise direction and encircled by the words “Safety squEASE®.” Thus, on the same cap, arrowheads mean two different things: One pair indicates location and the other pair indicates direction of movement. This may be a quibble about a detail, but design is really all about the details. And trying to follow poorly detailed directions can result in a headache.