Combination and Sequencing Matters

Adverse drug reactions are one of the leading causes of death in the United States today (Lazarou J, et al, 2008). In addition to the 1.5 million people a year who are admitted to the hospital because of adverse drug reactions, an additional three-quarters of a million people a year develop an adverse reaction after they are hospitalized. By paying close attention to potentially lethal drug combinations and planning the sequence of administration of drug combinations, nurses can prevent many adverse drug reactions.

In this month’s Tips to Treasure, RN.com highlights a few of the more common drug interactions that healthcare professionals should be aware of, as well as offering some tips on sequencing drug combinations:

• Warfarin and simvastatin (Zocor)-- There is an increased risk of bleeding problems, such as bleeding ulcers, rectal bleeding and easy bruising when these two drugs are administered together. This drug combination also increases the possibility of statin side effects like muscle pain and muscle tissue death.
• Niacin and either atorvastatin (Lipitor) or simvastatin (Zocor)-- Can increase the risk of muscle pain or muscle tissue death when these drugs are administered simultaneously.
• Lisinopril (Zestril, Prinivil) and potassium-- Increases the risk of hyperkalemia that may lead to heart attack or death.
• Ginkgo and aspirin-- Can cause an increased risk of bleeding problems. This may also occur when garlic pills and warfarin: are administered concurrently.

When a patient is prescribed several drugs, the sequence in which the ordered drugs are administered can influence the effectiveness and efficiency of the drug therapy. Some drugs interfere with absorption of others. For example, cholestyramine (Questran), colestipol (Colestid), and kaolin-pectin reduce absorption of a number of drugs including digoxin (Lanoxin) and are to be administered separately.

Often, several types of eye drops are prescribed for delivery to a patient at the same time. If one of the drops is a saline solution for moisturizing, administer the saline first so that the saline does not dilute or wash out the other eye drop medications. When more than one type of eye drop, ear drop, or inhalant is to be administered at the same time, determine whether the sequence of the medications is significant.

For additional tips on safely administering medications, please visit RN.com’s High Alert Medications.