Babies and children are particularly at risk when they're given the wrong drug, or when they get the wrong dose of the right drug. Medication errors not only delay treatment for the initial ailment, but they also can lead to bad side effects, serious harm, or even death.

One drug mix-up with tragic results occurred in an Indianapolis hospital in September 2006, when three premature infants received overdoses of the anticoagulant heparin and died. While an event such as that is quite rare, significant drug reactions in children may be more common than many people realize. A recent review of drug reactions that occurred in children during a hospital stay found that about 1 out of 10 experienced an adverse reaction; of those, 12 percent were severe.

Drug errors can happen when the name of one medication looks or sounds like another--a problem compounded by poor penmanship on doctors' prescriptions, sloppy pronunciation, mistaken memory, and hard-to-read labels. A recent report from the Institute of Medicine of the National Academies noted that up to 25 percent of errors reported were due to confusion caused by drugs having similar names.

Babies and children are vulnerable for two main reasons. First, their lower body weight makes them less tolerant than adults of variations in a drug's dosage. This can be a special concern when a drug--prescription or over the counter--is delivered with a dropper or a spoon because the measurement is less exact than a tablet.

Second, a drug's side effects can be harder to recognize in a child than in an adult. An adult can tell you if something is wrong, but a child may simply cry, and a caregiver may dismiss those cries as colic, a tantrum, or discomfort caused by the illness itself. A small child may not yet be able to speak or, even if verbal, may not have the vocabulary to express what's bothering him.

Here are some strategies for protecting your child from a drug mix-up:

• When your child's pediatrician prescribes a drug, ask the doctor to print the name for you and even spell it aloud. If it's a brand-name drug, make note of the generic name as well.
  
  
• Ask your child's pediatrician to briefly note the drug's intended purpose on the prescription form. That will enable the pharmacist to double-check the name against that indication.
  
  
• Before filling a prescription, have the pediatrician describe what the medication should look like. If you spot a difference in the color of the liquid or the color, size, or shape of the pills, tell your pharmacist immediately.
  
  
• Don't leave the pharmacist's counter until you've checked the label on the container to verify that it's the right drug.
  
  
• Choose over-the-counter medications by their active ingredients, not by brand name. Drug manufacturers often use well-established brand names to launch a series of related--but different--products.
  
  
• Find out what the side effects of the medication are. Once your child starts taking the drug, be alert to any unforeseen effects, which could signal a mix-up.
  
  
• Maintain a complete list of all the drugs your child takes, prescription and over-the-counter, including dosages as well as brand and generic names. Update the list regularly, and bring it with you whenever you visit the pediatrician or drugstore. For lists of soundalike or look-alike drugs, visit the Web site for the Institute for Safe Medication Practices or the United States Pharmacopeia.
  
  See Consumer Reports' free report on vaccinations, and free overviews of a range of children's health topics, for more information.