Bad Taste Makes Patients Avoid Drugs - Brief Article

USA Today (Society for the Advancement of Education), August, 2001

The innate desire to taste food and derive pleasure from that sensation is so strong that people sometimes stop taking life-saving medication simply because it tastes bad or ruins the flavor of otherwise enjoyable foods, according to psychologists Susan Schiffman and Jennifer Zervakis, Duke University, Durham, N.C. A series of studies analyzing the taste effects of certain medications found that specific drugs used to treat AIDS, heart disease, and depression either had a foul taste or significantly distorted the flavor of foods, which accounts for why some patients fail to take medications as recommended.

Just a short lapse in taking a prescribed medication can have a dramatic health consequence for some patients, Schiffman emphasizes, enabling the human immunodeficiency virus (HIV) to reach dangerously high levels or to build resistance against drugs used to fight it, for example. In one extreme case, a patient of Schiffman's found his AIDS medications so bitter and unpalatable that he refused to take them and consequently died.

"Distortions in taste and smell are far more than a nuisance, especially for patients whose conditions necessitate proper nutrition and a tightly controlled medication regimen," she points out. "Patients with sensory distortions can suffer from malnutrition, accidental poisonings, and chronic diseases like hypertension and diabetes that require the ability to taste, and thus regulate, salt or sugar intake"

Schiffman and Zervakis examined the taste impact of 63 different medications by applying them topically to the tongue's surface, a process that mimics how the drug is secreted in the saliva, but does not allow it to enter the bloodstream. Among the drugs analyzed were protease inhibitors and nucleoside analogs, two commonly prescribed classes of drugs used to reduce HIV loads and stave off the onset of AIDS symptoms. Three of the protease inhibitors--indinavir, ritonavir, and saquinavir--were described by subjects as bitter, medicinal, metallic, astringent, sour, and burning. All of the nucleoside analogs--didanosine, lamivudine, zidovudine, and stavudine--were cited as having the same unpleasant tastes. Patients with HIV (but not taking medications) perceived the drugs as being more bitter than did subjects without HIV, suggesting that the disease process itself altered taste perception to some degree.

While unpleasant physical side effects are a common excuse that patients cite for halting their medications, Schiffman argues that taste impairment is one effect that has received little attention, but is emerging as a critical factor in compliance. Several studies conducted around the nation have documented the noncompliance rate due to taste distortions.

"The senses of taste and smell are often overlooked as second-class citizens to the more obvious senses of sight, hearing, and touch, but their loss or distortion can have equally devastating consequences as the loss of sight, hearing, and touch," she maintains. Elderly people are at particular risk for taste and smell deficits because of their advanced age and the multitude of diseases from which they suffer. The sheer quantity and interaction potential of the drugs they take can further compound taste loss and distortions. That is one concern with certain anti-depressants and heart medications commonly prescribed in the elderly, Zervakis and Schiffman's studies found. Not only did the drugs taste bitter, but they altered taste perception of other foods to a significant degree.

Subjects tasting the heart drug captopril reported a reduction in the intensity of sweet, salty, and bitter tastes, while the heart drug procainamide increased the intensity of spiciness. All nine of the heart medications studied (labetalol HCI, captopril, diltiazem HCI, enalapril maleate, hydrochlorothiazide, propranolol HCI, mexiletine HCI, procainamide HCI, and propafenone HCI) were described as being predominantly bitter, with other negative qualities including metallic, medicinal, sour, sharp, and astringent.

The four tricyclic anti-depressants studied (clomipramine HCI, desipramine HCI, doxepin HCI, and imipramine HCI)produced similar taste complaints among all subjects, old and young. However, elderly patients required as much as seven times more of certain drugs than younger ones did before they could taste it.

Zervakis explains that taste distortions and deficits like these put all patients at risk--particularly the elderly--for ceasing to take critical medications and for consuming excess sugar, salt, and spoiled foods they cannot adequately taste. Additionally, many drugs cause foods to become unpalatable for patients, which affects not only nutrition, but mood and well-being.

Without taste and smell, elderly or sick people are unable to select appropriate food and portion sizes, and they eventually lose the primary reinforcement to eat--the pleasure derived from tasting and smelling food. That pleasure takes on particular importance among people for whom other sources of gratification--such as work, family, and hobbies--may be limited.