Some IV drugs pose a health risk to your patient(s) when utilized in conjunction with one another; these drugs are deemed "incompatible". Drug incompatibility occurs when one drug is not of suitable composition to be mixed with another drug, resulting in chemical alteration or destruction of one or both drugs. Incompatibility reactions occur inside a fluid container or IV line. Some drug incompatibilities result in precipitation, which is the formation of solids from a liquid solution that can be visibly seen as crystals, haziness, or turbidity. Others cannot be seen, but have chemical incompatibilities that result in inactive or toxic solutions.

Incompatible Drugs in EMS

Sodium Bicarbonate is an alkaline solution that should not come into contact with any other medications. It can precipitate some medications and inactivate others. For example, when sodium bicarbonate is mixed with calcium chloride, the mixture forms a visible white, cloudy solution.

When in contact with epinephrine, norepinephrine, or dopamine, sodium bicarbonate deactivates the effects of the drugs on the body. For these reasons, it is very important to flush the IV line well before and after the administration of sodium bicarbonate.

IV diazepam (valium) is incompatible with most drugs and fluids, including normal saline. When in contact with other fluids it precipitates as well.

For the same reasons, hydroxocobalamin (a synthetic form of vitamin B12) should not be administered in the same line as dopamine, fentanyl, nitroglycerin, or sodium nitrite

Consequences for the Patient

• Damage from toxic solutions
• Particulate emboli from crystallization
• Tissue irritation due to major PH changes
• Therapeutic failure

To prevent the negative effects of drug incompatibilities, understand the medications you are administering, and be alert for medications with a history of many incompatibilities. If mixing medications, always follow manufacturers' instructions and pay attention to changes in color in the IV line when pushing multiple medications. Remember, always follow your local protocols!