Injection Types and Volume Classification

Injections

• Injections constitute sterile drug solutions/suspensions in aqueous or nonaqueous vehicles.
• Administered via needle into almost any body part.
• Commonly injected into a vein (intravenous), muscle (intramuscular), skin (intradermal, or under the skin (subcutaneous).
• Parenteral route is any medication route other than the alimentary canal, hence including all injection routes.

Parental Product Classification by Volume

• Small Volume Parenteral (SVP): Ranging from 1-10 ml in ampules or prefilled disposable syringes, it's for single-dose use and rapid effect.
• Large Volume Parenteral (LVP): Ranging from 100 to 1000 ml, in plastic bags/glass containers.
  • Given by slow IV infusion.
  • Functions: supplying electrolytes/nutrients, blood volume restoration, prevents tissue dehydration, and dilutes toxic body fluids.
• Available as solutions/suspensions or as dry powder for reconstitution.

Intravenous (IV) Infusions

• Sterile, aqueous preparations administered intravenously in large volumes.
• Used to restore blood volume, provide electrolytes/nutrients/medications, and prevent tissue dehydration.
• Typically given to critical care, dehydrated, or malnourished patients, and those undergoing/recovering from surgery.
• Dosage can be solutions, fine nutrient dispersions, therapeutic agents or blood-based.
• Isotonicity not critical, some IV solutions are isotonic/close to it with blood as volumes rapidly dilute in circulation.

Common intravenous Infusion solutions

• 0.9% Sodium Chloride (NS) is normal saline.
• 0.45% Sodium Chloride (1/2NS).
• 5% Dextrose in Water (D5W or D5W).
• 10% Dextrose in Water (D10W or D10W).
• 5% Dextrose in 0.9% Sodium Chloride (D5NS or D5NS).
• 5% Dextrose in 0.45% Sodium Chloride D512NS or D51/2NS
• Lactated Ringer's (0.86% Sodium Chloride, 0.03% KCl, 0.033% Calcium Chloride) is written as LR
• 5% Dextrose in Lactated Ringer's (D5LR or D5LR).
• All solutions are prepared in Water for Injection, USP and may be used as vehicles for introducing more agents.

Example calculation

• Preparation of 250-mL bag of D5½NS: this requires 12.5 g of dextrose and 1.125 g of sodium chloride.

Comparing IV solutions

• Microdrip set with a rate of 60 drops/mL will require 3000 drops and 50 minutes to deliver 50 mL of IV solution.
• Standard set with a rate of 15 drops/mL, requires 750 drops and 12.5 minutes to deliver 50 mL.

Sodium chloride and dextrose

• A 1000mL IV bag of 0.18% sodium chloride and 4% dextrose contains 1.8 g of NaCl and 40 g of dextrose.

Additives

• A 500-mL IV bag of D5LR with additives contains these compounds in the following amounts:
  • 25g of 5% dextrose.
  • 4.3g of 0.86% NaCl.
  • 0.15g of 0.03% Kcl.
  • 0.165g of 0.033% CaCl2.

Intravenous Push (IVP) Drug Administration

• Is also Known as IV Stat or a bolus dose.
• It involves rapid intravenous medication injection during emergencies.
• Usually done in under a minute.
• Designed for quick control of heart rate, blood pressure, cardiac output, respiration, or other critical conditions.
• Safe administration needs precise dose and rate calculations.

IV Admixtures

• Involves adding one+ drugs to large-volume sterile fluids like sodium chloride, dextrose, or lactated Ringer's injection.
• Additives are generally small-volume sterile solutions in ampules/vials.
• Accurate checking of basic fluids, additives and calculations versus orders is critical.

Rate of Flow for IV Fluids

• Physicians set rates for intravenous fluids in milliliters/minute or drops/minute.
• The rate of drug administered (mg per hour), or administration duration for infusion volume is also set
• Pharmacists verify/perform flow rate calculations.

Using Rate-of-Flow Calculations

• With 10 mL of 10% calcium gluconate/ multivitamin infusion, mixed with a 500 mL of a 5% dextrose injection and infused over 5 hours (dropper calibrates 15 drops/mL) it should be set at approximately 26 drops per minute.
• 1000 mL D5W to be infused over 8 hours using a set that delivers 10 drops/mL requires about 21 drops per minute.
• Infusion of 10 mL of 1:5000 isoproterenol hydrochloride with 500 mL of 5% dextrose should be administered at 1.28 mL per minute to give 5 µg of isoproterenol hydrochloride per minute, taking about 6.5 hours in total.