Intravenous Drug Administration

Question 1

Name some of the reasons for IV drug administration

Answer 1

If the meds are not available in another form, it cannot be tolerated by diff route, constant/high blood levels of meds, rapid onset needed, Increased effectiveness, and to ensure compliance

Question 2

What are some of the disadvantages of IV administration?

Answer 2

Increased cost and time to administer, requires trained staff, rapid onset of meds can lead to hypersensitivity, volume of fluid to dilute meds, discomfort/pain to patient and health risks.

Question 3

Name some of the types of intravascular devices

Answer 3

Peripheral venous catheters, central venous catheters (peripherally inserted or skin tunneled) and arterial catheters. Then you have syringes, bags, pumps and drivers

Question 4

What are the different methods of administering intravenous medications

Answer 4

Continuous infusion, intermittent infusion and bolus injection

Question 5

Describe features of intermittent infusion

Answer 5

Used for:

• Unstable drugs,
• Long half-life,
• Concentration dependant effects,
• Less compatibility concerns

Question 6

Describe features continuous infusion

Answer 6

• Use of stable drugs,
• Short half-life,
• Time dependant effects,
• Needs dedicated IV site
  (as soon as you stop infusing then concentration in plasma will drop quickly)

Question 7

Describe features bolus injection

Answer 7

• Used when rapid response required,
• With incompatibilities,
• Unstable drugs

Question 8

What are the complications of IV drug administrations? (side effects)

Answer 8

• Fear/phobia/pain,
• Infection/sepsis,
• Thrombophlebitis,
• Extravasation/Infiltration,
• Emboli,
• Anaphylaxis/hypersensitivity,
• Overdose

Question 9

Describe what is meant by extravasation/ Infiltration

Answer 9

Extravasation - Where the catheter has been inserted into the tissue and injected vesicant or chemotherapy into surrounding tissue.
Infiltration - Catheter inserted into surrounding tissue and injects fluid/meds that cause mild inflammation and stretching.

Question 10

What is red man syndrome?

Answer 10

Hypersensitivity reaction due to histamine release causing erythematous rash of face, neck and upper torso. It can cause burning, itching and generalised discomfort.

Question 11

How is the incidence of red man syndrome reduced?

Answer 11

By slowing infusion rate and more dilute drug solution.

Question 12

What is the complications of IV drug administration with the medicine itself.

Answer 12

• Insufficient mixing
• Stability of medicines in solutions (due to light, temperature, concentration and pH)
• Interactions of medicines with the syringe/bag

Question 13

Define bioavailability and the percentage that IV injections

Answer 13

• The fraction of unchanged drug that reaches the systemic circulation. Bioavailability of IV = 100%

Question 14

Describe the elimination of drugs

Answer 14

For most drugs, the amount of drug eliminated per unit time is related to conc of drug in plasma. So higher concentrations more drug removed and with lower concentrations, less drug removed.

Question 15

Define what steady sate is?

Answer 15

It is when plasma concentration increases during infusion until the rate of input equals rate of output. This means it will plateau.

Question 16

Define clearance

Answer 16

The volume of blood or plasma cleared of drug per unit time. In 1st order kinetics the amount of drug eliminated change but the clearance stays the same.

Question 17

What is the plasma steady state concentration dependant on?

Answer 17

The rate of drug administered / clearance

Question 18

What is the elimination half life dependant on?

Answer 18

t1/2 is dependant on the volume of distribution and inversely on the clearance. So if volume of distribution increases then the half life increases. If clearance is decreased then half life is increased.

Question 19

The time taken to reach the plasma steady concentration is dependent on?

Answer 19

Elimination half life