Exam 2 Parenteral Products 3

Question 1

What does USP <797> have to say about IV and intra-spinal routes of administration?

Answer 1

CSPs are potentially more dangerous to patients when the CSPs are administered into the vascular (aka IV) and central nervous systems (aka intra-spinal) than when administered by most other routes

Question 2

What does it mean that IV is the “least forgiving” parenteral route of administration?

Answer 2

1. has immediate distribution → no line of defense if something goes wrong since it bypasses the body’s defenses
2. in general, if an excipient is acceptable for IV injection, it is acceptable for other parenteral routes of administration → but not always true
3. but some excipients that are acceptable for parenteral routes such as IM, for example, are totally UNACCEPTABLE for IV use → can put into muscle but not into bloodstream

Question 3

What are the methods of administration for IV?

Answer 3

1. bolus (push) → a shot in which everything goes in at once

2. infusion → over a period of time (not all at once)

Question 4

What are the different sites of administration for IV?

Answer 4

1. peripheral vein → on limbs (like the arm)

2. central vein → close to the heart so there is more blood flow, for prolonged and higher doses

Question 5

What are the different infusion modes of administration?

Answer 5

1. continuous administration → like the 24h in a day

2. intermittent administration → come every few hours and do it again in a given time period

Question 6

Why is the IV route characterized by a rapid onset of action?

Answer 6

there is no absorption step → for a drug to exert its effect, you take it and it gets dissolved and absorbed and then distributed to the site of action, but with IV, it’s already right there in the bloodstream

Question 7

What is characteristic of a bolus dose?

Answer 7

distributes quickly and gets eliminated quickly

Question 8

What is characteristic of IV infusion?

Answer 8

can get a fixed level of the drug which is an advantage of infusion parenterals (compared to tablets) → once the infusion has stopped being administered, the drug starts to be eliminated like an IV bolus dose

Question 9

What are some formulation considerations for IV injections?

Answer 9

1. usually aqueous solutions, but emulsions can be used such as parenteral nutrition (TPN) formulations
2. must not administer oil-based solutions not suspensions by the IV route → don’t want oil in the blood!
3. physiological pH and isotonicity are always very highly desirable but are not absolutely required → is a good thing or else we would be limited on which drugs can be administered by injection

Question 10

What are some IV suspensions that exist?

Answer 10

specialty (nanotechnology-based) in which nanoparticles can be administered by IV route

Question 11

What are some common venous complications?

Answer 11

1. phlebitis
2. thrombosis
3. thrombophlebitis

Question 12

What is phlebitis?

Answer 12

1. inflammation from the irritation of the tunica intima of the vein (inside wall of the vein)
2. moderate to severe discomfort
3. may take days to months to subside → have to use different site for injection since the body is not equipped to be hurt
4. limits veins available for future therapy

Question 13

What is an analogy related to phlebitis to help describe it?

Answer 13

Doritos like to stab you in the mouth but you keep eating it regardless → this is because the mouth tissue and GI tract are designed to be attacked all the time so the mouth starts to heal after being stabbed by the Dorito → veins are the complete opposite! → they are not designed to be cut on the inside so it takes them a very long time to heal

Question 14

What is thrombosis?

Answer 14

1. the formation of a blood clot (thrombus) in the vein → can stop blood flow and can have major organ damage so the patient can be in major trouble depending on where the clot goes → death or disabled
2. pain
3. swelling
4. pulmonary embolism → can be lethal if it goes to the lungs or brain

Question 15

Why should we worry about infusion rates?

Answer 15

1. the body can void about 3000 mL/day which is roughly between 100 and 150 mL/hr
2. small injection volumes can give very high injection rates that are not dangerous
3. large volumes can give very reasonable looking infusion rates that are in fact dangerous → example is like 100 mL/hr but if patient has kidney deficiency, can cause them serious problems

Question 16

What is the setup for continuous IV infusion?

Answer 16

the solution container (aka IV bag) that hydrates the patient with a drip chamber that counts the drops/min → no piggyback container

Question 17

What is the setup for intermittent IV infusion?

Answer 17

contains the piggyback container that is higher than the large volume container in which it has higher pressure so it will block the flow of the large volume container until the piggyback container is empty

Question 18

What is a central vein IV infusion?

Answer 18

from the arm like a catheter from the arm to the heart → IV goes into the vein not artery!

Question 19

Why is it important that the IV goes into the veins and not arteries?

Answer 19

arterial blood flow has stronger blood flow than veins → need a pump for arterial blood infusion

Question 20

What did metal syringes look like?

Answer 20

had the gauges printed/engraved on the metal syringe and they were reusable → would boil the syringes to disinfect them

Question 21

What are the different sites of intramuscular administration and the typical maximum volumes of administration?

Answer 21

1. deltoid muscle → about 2 mL
2. thigh → about 5 mL
3. gluteal muscle → about 5 mL

Question 22

What is the difference between IV and IM in terms of the volume that can be injected?

Answer 22

IV allows flexibility since it can put small or large volume compared to IM that only allows small volumes

Question 23

What is the comparison between the onset of action between IM route and oral route?

Answer 23

IM route is characterized by an absorption step (since it is not administered directly into the blood so it has to go through absorption first) → onset of action is not always faster than oral → unless it is a local anesthetic in which it will work right away

Question 24

What are some things to note about the subcutaneous route of administration?

Answer 24

1. similar to the IM route, except that the volume administered usually does not exceed 1.5 mL (aka smaller volume than IM injections) → example is insulin shots
2. absorption tends to be slower than IM because of lower vascularization of the tissue → has to cross some barriers before getting to the muscle then to blood (has more barriers to go through than IM injections)
3. infusion by subcutaneous route is called hypodermoclysis
4. formulation considerations are similar to those for the IM route (close in injection site area)

Question 25

What does the plasma concentration v time graph look like for the different routes of administration?

Answer 25

1. IV bolus gets eliminated rapidly but starts out very high
2. IM goes up faster (aka faster absorption) and then goes down (having higher concentration than SC) → closer to the vein so it is faster than SC
3. SC goes up slower (aka slower absorption) and not as high and then goes down → is farther from the vein so it’s slower

Question 26

What affects the rate of absorption?

Answer 26

formulation and physiological factors

Question 27

What are the two types of intra-spinal routes of administration?

Answer 27

1. intrathecal

2. epidural

Question 28

Intra-spinal routes of administration are commonly used for what?

Answer 28

used for anesthesia

Question 29

What is the intrathecal route of administration?

Answer 29

into the subarachnoid space and cerebrospinal fluid

Question 30

What is the epidural route of administration?

Answer 30

into the space at the thoracic or lumbar level between the dura mater and the vertebral canal (epidural space) → more commonly used than intrathecal

Question 31

What is the dura mater?

Answer 31

the dura mater is the layer that isolates the spinal cord from everything else → if crosses the dura mater, you’re on the extension of the brain (aka basically inside the brain!)

Question 32

What is the major difference between intrathecal and epidural?

Answer 32

epidural is right outside spinal space (not yet inside or crossed the dura mater) while intrathecal is inside the space and has crossed the dura mater (now directly into the brain)

Question 33

What is the spinal space?

Answer 33

aka the subarachnoid space that contains cerebrospinal fluid

Question 33

What are some things to know about intrathecal route of administration?

Answer 33

1. a bolus administration directly into the CSF (in brain!)
2. continuous administration not recommended (want to go in and out)
3. meds have higher potency than epidural
4. no membranes (dura) to cross so the drug goes straight into the CSF

Question 34

What are some things to know about the epidural route of administration?

Answer 34

1. bolus or continuous administration
2. in neonates → at the caudal level near the tip of the tailbone (the sacrum) into a small opening (sacral hiatus) → very difficult to do in neonates

Question 35

What is special about epidural needles?

Answer 35

1. have little bars on the needle like a ruler to measure how far in and how far still left to go in
2. tip is to minimize poking things it shouldn’t be poking
3. epidural needles do not have a bevel → more of a curvature

Question 36

What is the major difference between the sites of administration for intrathecal and epidural routes of administration?

Answer 36

intrathecal is into the subarachnoid space while epidural is between the dura mater and the vertebral canal

Question 37

What is the special care regarding intra-spinal routes of administration?

Answer 37

1. cannot get away with not being isotonic → HAVE TO BE ISOTONIC
2. cannot get away with not having physiological pH → HAVE TO HAVE PHYSIOLOGICAL PH
3. cannot have preservatives → NO PRESERVATIVES

Question 38

Why does the gauge of the needle even matter with intra-spinal routes of administration?

Answer 38

the volume of the tubing (aka the gauge) can have a difference in how it works → need to contact the manufacturer since all gauges are different with each manufacturer

Question 39

What are some important things to remember?

Answer 39

1. in general, if an injectable excipient is tolerated by the IV route, it will be well tolerated by the IM or SC routes → but not always the case (aka citrates)
2. the terms parenteral and IV are not synonyms → parenteral is big overarching category while IV is a subset of parenterals
3. every IV product is a parenteral but not every parenteral product is an IV → IV is subset of parenterals
4. IV route has no absorption step → straight into the bloodstream
5. the IM and SC routes do have an absorption step → because not straight into the bloodstream
6. parenteral routes of administration bypass hepatic first pass metabolism → don’t lose as much of the drug (as if it was taken orally) since it bypasses the liver and won’t get metabolized by it

Question 40

Which route is the most stringent?

Answer 40

intra-spinal since it goes to the brain!

Question 41

All products have what requirements?

Answer 41

1. right potency

2. properly labeled

Question 42

All parenterals have what requirements?

Answer 42

1. right potency
2. properly labeled
3. sterile
4. free of particles
5. free of pyrogens

Question 43

Intra-spinal products have what requirements?

Answer 43

1. right potency
2. properly labeled
3. sterile
4. free of particles
5. free of pyrogens
6. isotonic
7. has physiological pH