IV Compatibilities and Incompatibilities

Question 1

Drug compatibility

Answer 1

Ability to mix two or more drugs without adverse physical or chemical reactions

Question 2

Drug incompatibility

Answer 2

In vitro reactions between drugs that result in degradation or changes affecting drug efficacy or safety

Question 3

Physical compatibility

Answer 3

No visible changes e.g. precipitation, crystallisation

Question 4

Chemical compatibility

Answer 4

No degradation or reaction between drugs

Question 5

Therapeutic compatibility

Answer 5

No pharmacological antagonism or toxicity.
Drug works together

Question 6

Physical incompatibility

Answer 6

Precipitation or phase separation

Question 7

Chemical incompatibility

Answer 7

Degradation of >10% - 10% potency lost meaning drug is expired

Question 8

Therapeutic incompatibility

Answer 8

Diminished therapeutic effect or increased toxicity

Question 9

Causes of incompatibility

Answer 9

pH differences - precipitation or degradation when drugs have different pH levels
Solubility issues - incompatible drugs may precipitate out of solution
Drug concentration - high concentrations increase the risk of incompatibility
Diluents - using incompatible diluents can destabilise drug mixtures
Temperature sensitivity - temperature influences chemical reactions where heat can speed up degradation

Question 10

Y-site administration

Answer 10

Practice of administering two or more drugs through the same IV site
Common in ICU due to the need for multiple infusions
Consider - diluent, concentration and pH

Question 11

Syringe drivers

Answer 11

Small, portable infusion pump used to deliver continuous SC or IV infusions over a specified period, often 24 hrs
Drugs must remain stable and compatible through the infusion period as they sit in the syringe for a long time
Consider - pH of the solution and individual stability of each drug

Question 12

Consequences of drug incompatibility

Answer 12

Catheter occlusion - drug precipitates block catheters
Therapeutic failure - incompatible drugs degrade, reducing efficacy
Severe reactions - embolism or toxicity can increase patient mortality

Question 13

Multi-lumen catheters

Answer 13

Specialised catheters with multiple channels (lumens) within one tube
Enable simultaneous administration of fluids, medications and blood draws
Reduces multiple IV lines and prevents drug incompatibility
Used in critical care, anaesthesia and long-term therapy

Question 14

Filtration as prevention strategy

Answer 14

In line filters - devices inserted into IV lines to filter out particles, air bubbles that causes air embolism or contaminants from solutions before they enter the bloodstream
Prevents particulate matter from reaching bloodstream, reducing risk of embolism
Recommended for drugs prone to precipitation

Question 15

Common incompatibility scenarios

Answer 15

Antibiotics + Electrolytes - e.g. Ceftriaxone and Calcium
Cardiovascular agents + pH mismatch - e.g. Dopamine + Sodium Bicarbonate
Midazolam and Vancomycin - leads to precipitation
Phenytoin and Dextrose - incompatible