Since Celebrex went on the market in January, the Food and Drug Administration has received at least 95 reports of errors by physicians and pharmacists, who confused the drug for Celexa, a depression treatment, and Cerebyx, an anti-seizure drug.
Monsanto actually had changed the drug's name before from Celebra, after federal regulators said it resembled other brand names. Pharmacists say the reported mix-ups occur because they are unable to read the doctors' handwriting.
None of the cases involved serious injury or death, and there were only 22 cases in which a patient took the wrong drug. At the urging of federal regulators, the two companies that jointly sell Celebrex - Monsanto Co. and Pfizer Inc. - have recently tried to clarify the differences between their product and others with an educational campaign aimed at medical professionals.
Monsanto officials said the percentage of mix-ups occurring with the drug are small compared to the high volume of prescriptions written so far, which is expected to make the company more than $1 billion in sales this year.
But medical experts note that reports to the FDA are voluntary, and many more mix-ups may have taken place.
"We are still concerned about the problem," FDA official Jerry Phillips told the Associated Press. "This is a significant number of errors."
The FDA says hundreds of drugs have similar names. The problem of possible medication mix-ups is clear when comparing the names of some other prescription drugs:
- Nicoderm (for quitting smoking) and Nitroderm (for angina).
- Accutane (for acne) and Accupril (for hypertension.
- Rimantadine (for flu) and Ranitidine.
- Paxil (for depression) and Paclitaxel (for ovarian cancer).
- Proventil (for asthma) and Prinivil (for hypertension).
- Zyrtec (for allergies) and Zyprexa (for psychoses).
Experts say doctors, in turn, need to be careful how they spell the drug on prescription sheets, and pharmacists should double check that the treatment is compatible with other medications the patient may have ordered from the pharmacy.
Monsanto and Pfizer have paid for advertisements in major medical journals to make sure doctors and pharmacists understand the difference between the similar-sounding drugs.
Celexa is made by Forest Laboratories, and Cerebyx, by Warner-Lambert.