A Taste of Taxol

Pets can become an integral part of the support system of a patient facing debilitating or life-threatening disease. Unintended, this close proximity can lead to health risks for both patient and animal. Recently, one of our patients required consolation and support during an overnight hospitalisation after her chemotherapy course, because she became upset upon realising that she had been poisoning two of her three pets.

The patient was a 60-year-old woman who received paclitaxel (125 mg/m²) and carboplatin (300 mg/m²) for stage IV ovarian cancer. After the first two courses, she had noticed that her Yorkshire terrier and one of her two cats suffered from considerable hair loss, leading to baldness mimicking that of their master. The second cat remained unaffected. During the sleepless night, worrying over her affected dog and cat, she figured out that her pet-feeding habit might be to blame. She fed her dog with the inside of chocolate bonbons, because he hated the chocolate cover. Since the dog became almost addicted to them, she licked off the chocolate every time before feeding the content of the bonbon to the dog. The affected cat became accustomed to meat that had been tested and adapted for temperature in her mouth, and later on pre-chewed by her before feeding it to the cat. Both animals grew bald, while the second cat, who was completely self-supporting, did not. Consulted veterinarians could not establish any apparent cause for the alopecia. After consoling her, we advised her to stop this practice during chemotherapy; both affected animals subsequently regrew their fur. Approximately 4 weeks after the end of chemotherapy, the patient started giving food to her two pets in the aforementioned manner, without adverse effects.

Directed by the observations of the patient, we have measured saliva and blood concentrations during a treatment course in our patient (Table 1). Blood concentrations and pharmaco-kinetic measurements were in compliance with the reports from the literature (Huizing et al 1993). Paclitaxel was detected in saliva in concentrations that are relatively low in comparison with reports in other body fluids; however, pharmacologically relevant levels (0.05–0.1 μM) were detected (Huizing et al 1993). Transfer of drugs by saliva to patient's pets is possible, yet oral resorption of paclitaxel is poor. The observations mentioned above support the argument that apparently in this patient's pets, the oral uptake of paclitaxel was sufficient to induce alopecia.

Table 1.

Plasma and saliva concentration of paclitaxel

	Plasma	Saliva
t=0	0	0
t=4 (end of infusion)	3787 ng/ml	112 ng/ml
t=5	1493	42
t=5.5	848	51
t=6.5	550	38

Clearance: 290 ml/min/m².

We conclude that paclitaxel can be detected in saliva shortly after an in vitro gift. As is shown in our patient, pets can occasionally run unexpected risk from their owner, but we would otherwise consider this message as frivolous.