Reminyl and Amaryl don't look alike, but when said aloud they're easily confused. The result: Some doctors and pharmacists have given Amaryl (glimepiride), a diabetes drug, to Alzheimer's patients who are supposed to take Reminyl (galantamine hydrobromide), and vice versa. This from a May 2005 warning by the U.S. Pharmacopeia (U.S.P.) which sets official standards for drug manufacturing, packaging, and labeling. The patients involved not only failed to receive adequate treatment of their real problem, but some suffered adverse events as a result. Ortho-McNeil, maker of Reminyl, responded by changing the name of its drug to Razadyne.

Some 15 percent of drug errors occur when the name of one drug looks or sounds like another, a problem compounded by poor penmanship, sloppy pronunciation, mistaken memory, and hard-to-read drug labels. The U.S.P. has a list of over 1,000 pairs of sound-alike or look-alike names on its Web site (www.usp.org).

The table below lists some of the confusing drug pairs that include commonly prescribed medicines or have most often led to documented cases of patient harm. Each row in the table shows two drugs with confusingly similar names, listed in capital letters. Those highlighted names may be either the brand name (listed first within each box) or the generic name (listed second, in parentheses).

ACCUPRIL (quinapril) for hypertension
ACIPHEX (rabeprazole) for heartburn and ulcers

AMBIEN (zolpidem) for insomnia
AMEN (medroxyprogesterone) to control menstrual cycles

CELEBREX (celecoxib) for arthritis
CELEXA (citalopram) for depression

CLOZARIL (clozapine) for schizophrenia
COLAZAL (balsalazide) for ulcerative colitis

Deltasone, Orasone, others (PREDNISONE) for inflammation
Mysoline (PRIMIDONE) for seizures

Flumadine (RIMANTADINE) for influenza
Zantac (RANITIDINE) for heartburn and ulcers

FOSAMAX (alendronate) for osteoporosis
FLOMAX (tamsulosin) for enlarged prostate

LAMICTAL (lamotrigine) for epilepsy
LAMISIL (terbinafine) for fingernail fungus

OXYCONTIN (oxycodone) for pain
Ditropan (OXYBUTYNIN) for urinary incontinence

PAXIL (paroxetine) for depression
PLAVIX (clopidogrel) to prevent heart attack and stroke

PRAVACHOL (pravastatin) for high cholesterol
Inderal (PROPRANOLOL) for hypertension

SINGULAIR (montelukast) for asthma
SINEQUAN (doxepin) for depression and anxiety

Thorazine (CHLORPROMAZINE) for severe psychotic behavior
Diabinese (CHLORPROPAMIDE) for diabetes

Valium (DIAZEPAM) for anxiety, muscle spasms
Ativan (LORAZEPAM) for anxiety

XANAX (alprazolam) for anxiety
ZANTAC (ranitidine) for heartburn and ulcers

ZYPREXA (olanzapine) for bipolar mania, and schizophrenia
ZYRTEC (cetirizine) for allergies

To prevent drug errors, it's essential that you obtain key information from your doctor and pharmacist about the drugs you're taking: what they're for, what the dosage should be, how long you should take them, what the possible side effects are, even what they look like. Supplement that information with your own research.