On September 19, 2007, researchers at the National Institutes of Health in Bethesda, Maryland presented research showing that 12 percent of patients on the anti-fungal drug Vfend experience hallucinations.

Patient stories of hallucinations presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy in Chicago, Illinois, include one cancer patient who saw a “Wookie,” the 7-foot tall alien of Star Wars fame, standing over his bed. Among the reported incidents of hallucinations were patients who saw scenic images of Montana or saw an unfamiliar person enter their room.

One doctor expressed concern that the hallucinations may cause some patients to be mistakenly diagnosed as psychotic. John E. Bennett, head of the clinical mycology section of the National Institute of Allergy and Infectious Diseases, says it is important for physicians to be aware of the side effects, so they don’t make such a mistake.

“These people aren’t going crazy,” Bennett said. “They’re lucid and oriented.”

About 13 million people take Vfend to treat fungal infections, according to statistics from Pfizer, the manufacturer of Vfend. Hallucinations appear to begin within 24 hours of starting the drug, appear most often in patients who are taking the drug intravenously, and often disappear when the patient is switched to a pill form.

Current data does not explain the reason for the hallucinations, but Pfizer representatives have said that the hallucinations are well-documented and not a big enough concern to keep the drug off the market.

“Cases of treatment-emergent hallucinations have occurred in clinical studies and are described in the product labeling for Vfend,” said Shreya Prudlo, a spokeswoman for Pfizer. “Health care professionals should be aware of the risk of this potential side effect so they are able to manage this symptom and reassure patients.”

Source: Elizabeth Lopatto, “Wookie Sighting? Pfizer Drug Causes Hallucinations,” Bloomberg.com, September 18, 2007.