Isotonicity

Definition

Isotonicity is the state in which two solutions have the same osmotic pressure across a semipermeable membrane. In pharmacology, it is important for ensuring that intravenous solutions do not cause cells to shrink or swell.

5 Must Know Facts For Your Next Test

1. Isotonic solutions have an osmolality similar to that of blood plasma, around 275-295 mOsm/kg.
2. Common isotonic solutions used in clinical settings include normal saline (0.9% NaCl) and lactated Ringer's solution.
3. Administering isotonic solutions helps maintain fluid balance without causing fluid shifts between compartments.
4. Isotonicity is crucial for avoiding cellular damage during intravenous therapy.
5. Checking the isotonicity of a solution ensures compatibility and safety when formulating medications.

Review Questions

• What is the osmolality range of isotonic solutions?
• Why is isotonicity important in intravenous therapy?
• Name two common isotonic solutions used in healthcare.

Related terms

Hypertonic: A solution with a higher osmotic pressure than another solution, causing cells to shrink.

Hypotonic: A solution with a lower osmotic pressure than another solution, causing cells to swell.

Osmolality: A measure of solute concentration defined as the number of osmoles of solute per kilogram of solvent.