Improving tastes of liquid antibiotics

July 2004

Liquid medication dosage forms are most often used in infants and young children due to ease of use and administration. Many medications, however, are not commercially available in liquid dosage forms. Fortunately, many antibiotics are available as liquids.

Several factors determine the acceptability of a specific medication by patients, caregivers and clinicians, such as cost. Taste is also an important determinant. The risk of not completing a liquid antibiotic course likely increases with poor acceptance of taste by the patient.

Several characteristics besides taste determine the palatability and acceptability of a specific liquid antibiotic by a child. Smell, texture and aftertaste are other determinants. Some liquid antibiotics may have a pleasant smell and initial taste, yet a strong bitter aftertaste may cause administration of subsequent doses to be difficult. A thick, sand-like texture also can contribute to reduced acceptance of a product by a child. A product’s palatability is additionally determined by not only the active drug but also the product’s excipients and specific pharmaceutical formulation.

Taste tests

In an attempt to assess the tastes of liquid antibiotic products, many taste tests have been conducted and their results published. Most studies have been conducted in adults, although several have been conducted in children. Taste tests usually evaluate the liquid antibiotic products in a manner analogous to wine testing, grading the product’s smell, texture, taste and aftertaste.

Liquid antibiotics that have commonly scored high include Lorabid (loracarbef, King), Suprax (cefixime, Lupin), Keflex (cephalexin, Lilly), Cefzil (cefprozil, Bristol-Myers Squibb), Ceclor (cefaclor, Lilly), Omnicef (cefdinir, Abbott), and Trimox (amoxicillin, Apothecon). Antibiotics that have scored poorly include Vantin (cefpodoxime, Pharmacia and Upjohn), Ceftin (cefuroxime, GlaxoSmithKline), Dynapen (dicloxacillin, Apothecon), Biaxin (clarithromycin, Abbott), VeeTids (penicillin V, Apothecon), Pediazole (erythromycin-sulfisoxazole, Ross Labs), and Sulfatrim (trimethoprim-sulfamethoxazole, Alpharma). The palatability of Zithromax (azithromycin, Pfizer) has been evaluated in several studies and compared with Biaxin, and it has outscored Biaxin in all studies.

In assessing the results and applicability of these taste tests, it is important to note that specific products may have been reformulated to enhance tastes since publication of these studies. Thus, while it still may be appropriate to use this information in daily practice, it remains wise to frequently elicit feedback from patients and caregivers on the patient’s acceptability of specific products, including brand and generic formulations.

It is interesting to note taste test results of the antibiotics recently recommended for the treatment of acute otitis media. As stated above, two of these antibiotics, Vantin and Ceftin, unfortunately have not scored well. This is largely due to these products’ bitter aftertastes. Amoxicillin has generally scored well, as has Omnicef. One study (Chan) compared two amoxicillin products – Amoxil (GlaxoSmithKline) and Trimox. While both products scored well overall, Trimox scored significantly better than Amoxil. This study additionally indicates that not all products of the same antibiotic have similar tastes. Several taste tests have revealed that some generic products scored equally well compared with brand products (eg, Pediazole, Keflex), while other generic products scored below brand products (eg, Bactrim [Women First Healthcare], Septra [Monarch] [both trimethoprim-sulfamethoxazole]). Augmentin (amoxicillin-clavulanate, GlaxoSmithKline) has been evaluated in several studies; it scored above average in one study and below average in others. It has not consistently been ranked as either good or poor.

Testing compliance

Several studies have additionally attempted to evaluate and correlate antibiotic taste with compliance. Compliance has been assessed by several means, including number of doses attempted and given, drug volume remaining at study conclusion, parent interview and urine testing for microbial bioinhibition. Although differences in palatability and taste perception were often noted by children enrolled in these studies, compliance did not differ in most of the studies. This may indicate the difficulty in accurately measuring compliance or, perhaps more likely, that factors contributing to medication adherence are more complex than one may assume. While product taste is likely to be an important consideration, other factors may include caregiver characteristics (eg, skill of medication administration).

Pharmacies have the opportunity to enhance the palatability of not only liquid antibiotics for children but also other liquid medications (including some over-the-counter [OTC] products) for children and adults. Two commercial flavoring systems are available to pharmacies: FLAVORx and Professional Compounding Centers of America (PCCA).

FLAVORx Medical Flavoring System of Bethesda, Md., (www.flavorx.com) allows pharmacies to enhance the tastes of more than 200 liquid and other oral medications, including prescription (eg, antibiotics, antiseizure medications) and OTC products. More than 40 different flavors are available for patients and caregivers to choose from.

The patient may be offered different flavors, depending upon the specific antibiotic or product. When a flavor is chosen, the pharmacist follows a specific recipe and adds flavoring agents and, with some particularly bitter liquid products, bitterness suppressors. The most commonly requested flavor is bubble gum, with grape and watermelon close behind. The number and variety of available flavors is quite interesting, including banana, banana-orange, butterscotch, citrus punch, raspberry, sour apple, coconut, pineapple, licorice, root beer, cinnamon, peach, blackberry and lemon, among others. Even coffee, pina colada, mocha cappuccino, pumpkin pie and candy cane are available. FLAVORx reports that, upon special request, macaroni-and-cheese flavoring has also been made available.

Because some liquid antibiotic products, such as Ceftin or Biaxin, have textures that some children may find unpleasant (thick and gritty) and may be bitter, FLAVORx additionally recommends that white grape juice be given immediately following administration of a dose, as this may help reduce the bitter aftertaste. Clinicians may use the Web address above to locate a pharmacy in their geographic area that offers this flavoring system. Information on the FLAVORx Web site states that the stability of antibiotics is unaffected when flavoring enhancers are added, as determined by stability studies. The approximate additional charge to the patient for flavor enhancement is $2 to $3.

PCCA of Houston (www.pccarx.com) offers pharmacies a flavoring system similar to FLAVORx, with recipes for specific products, including a variety of flavors, such as bubble gum, cheesecake, chocolate hazelnut, crème de menthe, cran-raspberry, guava, honey and butterscotch, among others. Financial charges to the patient for PCCA flavoring are similar to FLAVORx.

Several noncommercial flavoring enhancement tips can be found in the literature or have been suggested by various antibiotic manufacturers. Perhaps the most commonly recommended (and enticing!) includes administration of chocolate syrup before and after each antibiotic dose. The relatively strong taste of chocolate may be able to mask the taste of some antibiotics, in addition to coating the tongue, which may partially suppress bitter-tasting antibiotics. It has also been suggested to administer graham crackers after a dose, for when chewed, graham crackers may be able to remove drug particles remaining on the tongue (which may contribute to an unpleasant aftertaste). Popsicles may also help mask unpleasant tastes as well as provide a beneficial effect from cold temperature upon taste perception. Another commonly recommended means for taste masking is mixing the antibiotic dose with strawberry or raspberry jam. This method can also be employed for crushed tablets or capsule contents.

Lastly, if prescribing Biaxin, clinicians should remind caregivers not to refrigerate this product, as refrigeration increases its thickness and may contribute to increased perceptions of an unpleasant texture. Data on the stability of reconstituted antibiotic suspensions when the above flavoring tips are used are rare. One manufacturer (GlaxoSmithKline) studied the stability of Ceftin when diluted in 10 mL of the following liquids and found these combinations compatible: milk (white and chocolate), apple juice, orange juice, grape juice and lemonade.

For more information:

• Chan DS. Antimicrobial liquid formulations: a blind comparison of taste of 13 commonly prescribed medications. J Pharmacy Technol. 1997;13:206-209.
• Vaughen VC. Some children’s medicine should taste icky. Pediatr Rev. 1992;13:195.
• El-Chaar GM. Randomized, double-blind comparison of brand and generic antibiotic suspension: II. A study of taste and compliance in children. Pediatr Infect Dis J. 1996;15:18-22.
• Bell EA. Tastes of liquid medications: pediatric implications. J Pediatr Pharmacy Pract. 1999;4:43-50.