L21 Routes of administration Flashcards
(111 cards)
1
Q
What is a dosage form?
A
The physical form in which medication is delivered into the body.
2
Q
What are the three major considerations when choosing a dosage form?
A
Therapeutic considerations, drug property considerations, and biopharmaceutical considerations (ADME).
3
Q
Define enteral administration.
A
Drug administration into the gastrointestinal tract, usually orally or rectally.
4
Q
Define parenteral administration.
A
Drug administration by routes that bypass the gastrointestinal tract (e.g. injection), avoiding first-pass metabolism.
5
Q
What are the main solid dosage forms?
A
Tablets, capsules, suppositories, powders, and implants.
6
Q
Name three liquid dosage forms.
A
Solutions, suspensions, and emulsions.
7
Q
Name three semi-solid dosage forms.
A
Creams, ointments, and gels.
8
Q
List three advantages of oral drug delivery.
A
Convenient and non-invasive, good patient compliance, wide range of dosage forms available.
9
Q
List three disadvantages of oral drug delivery.
A
Slow onset, first-pass metabolism, variable absorption.
10
Q
Why is parenteral drug delivery used?
A
For rapid absorption, in unconscious patients, or when drugs are poorly absorbed orally.
11
Q
Why must parenteral drugs be sterile?
A
To prevent infections and ensure safety due to direct entry into the body.
12
Q
What determines the rate of absorption for injected drugs?
A
Whether the drug is in solution or suspension, and whether it’s in aqueous or oily vehicle.
13
Q
Describe the IV route.
A
Aqueous solution injected into a vein; rapid onset, bypasses first-pass metabolism. 25 degree angle
14
Q
Describe the IM route.
A
Injected into skeletal muscle; aqueous solutions absorb quickly, oily forms provide slow, sustained release. 90 degree angle
15
Q
Describe the ID route.
A
Injected into the dermis; slow absorption, used for small volumes like vaccines. 10-15 degree angel
16
Q
Describe the SC route.
A
Injected into loose tissue; absorption depends on molecular weight and lipophilicity. 45 degree angle
17
Q
Name two vehicle types that modify drug solubility.
A
Water-miscible solvents (e.g. alcohols), and water-immiscible oils (e.g. almond oil).
18
Q
List two advantages of parenteral delivery.
A
Rapid onset (IV), bypasses issues with poor oral bioavailability.
19
Q
List two disadvantages of parenteral delivery.
A
Painful, requires aseptic technique and trained staff.
20
Q
Why must IV solutions be isotonic with blood?
A
To prevent damage to blood cells and ensure compatibility with the circulatory system.
21
Q
What is a route of administration?
A
The path by which a drug is taken into the body to reach the site of action.
22
Q
What are the two major routes of administration?
A
Enteral (via GI tract) and Parenteral (bypassing GI tract).
23
Q
What are the subcategories of the enteral route?
A
Oral, sublingual, buccal, and rectal.
24
Q
What are the subcategories of the parenteral route?
A
Intravenous (IV), intramuscular (IM), subcutaneous (SC), intradermal (ID), and intrathecal.
25
Why is the route of administration important?
It affects onset, intensity, duration of drug action, patient compliance, and formulation design.
26
Name five oral dosage forms.
Tablets, capsules, solutions, suspensions, emulsions.
27
What is first-pass metabolism?
Metabolism of a drug by the liver before it reaches systemic circulation, reducing bioavailability.
28
Name two oral routes that bypass first-pass metabolism.
Sublingual and buccal routes.
29
Give one example each of drugs given via sublingual and buccal routes.
Sublingual – Nitroglycerin; Buccal – Prochlorperazine.
30
What must all parenteral formulations be?
Sterile, pyrogen-free, and isotonic.
31
Compare IV and IM administration in terms of onset and duration.
IV – rapid onset, short duration; IM – slower onset, longer duration (especially with oily vehicles).
32
What is the difference between an aqueous and oily vehicle in injections?
Aqueous – fast drug release and absorption; Oily – sustained, slow release.
33
What volume is typically used for SC injections?
0.5–2 mL.
34
What are common SC injection sites?
Upper arm, abdomen, thigh.
35
What is the typical use of the ID route?
Diagnostic tests (e.g. tuberculin skin test), vaccines.
36
Name three mucosal routes of administration.
Nasal, vaginal, rectal.
37
What are the advantages of nasal delivery?
Rapid absorption, avoids first-pass metabolism, useful for peptides/proteins.
38
What is a limitation of vaginal drug delivery?
Localised effect; less suitable for systemic absorption.
39
What are the characteristics of rectal administration?
Partial avoidance of first-pass metabolism; useful for unconscious patients or those with vomiting.
40
What properties of the drug affect route selection?
Solubility, stability, permeability, pKa, molecular weight.
41
What are important excipients in parenteral formulations?
Solvents (e.g. water for injection), co-solvents (e.g. ethanol), buffers, preservatives, antioxidants.
42
What is an emulsion?
A biphasic liquid dosage form of two immiscible liquids, stabilised by emulsifiers.
43
Why might a depot injection be used?
To provide prolonged drug release and reduce dosing frequency (e.g. IM oil-based injections).
44
What are three major advantages of enteral routes?
Safe, convenient, inexpensive.
45
What are three disadvantages of enteral routes?
Variable absorption, degradation in GI tract, first-pass effect.
46
What are three advantages of parenteral routes?
Rapid action, suitable for unconscious patients, avoids GI degradation and first-pass.
47
What are three disadvantages of parenteral routes?
Invasive, risk of infection, requires sterile technique and trained personnel.
48
Why is morphine often given parenterally in hospitals?
To achieve rapid pain relief and avoid variable oral absorption and first-pass metabolism.
49
Why might insulin be given subcutaneously?
To allow slow, steady absorption into circulation; oral insulin would be degraded in the GI tract.
50
What determines whether a drug is suitable for IV use?
Water solubility, pH compatibility with blood, absence of particulate matter.
51
How does the route of administration influence bioavailability?
Bioavailability is highest for IV (100%) and varies for other routes due to absorption barriers and first-pass metabolism.
52
What is the significance of drug lipophilicity in parenteral absorption?
Lipophilic drugs can diffuse more easily across biological membranes, enhancing absorption via IM or SC routes.
53
Why might a drug given orally have delayed onset of action?
Due to disintegration, dissolution, gastric emptying time, and intestinal transit before absorption.
54
Name three methods to sterilise parenteral preparations.
Autoclaving (moist heat), dry heat, filtration through 0.22 µm membrane.
55
Why is pyrogen testing necessary for injectable formulations?
Pyrogens (e.g. bacterial endotoxins) can cause fever and inflammatory reactions even if the solution is sterile.
56
What is the significance of isotonicity in injectables?
Prevents haemolysis or crenation of red blood cells; maintains cellular integrity.
57
What excipients help control tonicity?
Sodium chloride, dextrose, mannitol.
58
What are sustained-release (SR) formulations and when are they used?
Formulations designed to release drug slowly over time to maintain plasma levels and reduce dosing frequency — ideal for chronic conditions.
59
Name an example of an IM depot injection.
Haloperidol decanoate – used for long-term schizophrenia management.
60
How does an emulsion enhance drug delivery?
Improves solubility of lipophilic drugs; can allow controlled or targeted release.
61
What is intrathecal administration and when is it used?
Injection into the cerebrospinal fluid (CSF); used for spinal anaesthesia or CNS infections when drugs must bypass the blood-brain barrier.
62
What is the inhalation route used for, and why is particle size important?
Used for respiratory drugs (e.g. salbutamol); particles 1–5 µm are optimal for alveolar deposition.
63
Why is the transdermal route useful for some medications?
Provides continuous systemic delivery, bypasses GI tract and first-pass metabolism (e.g. nicotine, fentanyl patches).
64
Compare rectal vs. oral drug administration in terms of absorption.
Rectal may provide partial first-pass avoidance and is useful when oral route is not possible (e.g. vomiting), but absorption is often erratic.
65
Compare sublingual vs. buccal delivery.
Both avoid first-pass; sublingual acts faster due to richer blood supply; buccal may be better for sustained release.
66
Compare IV bolus vs. IV infusion.
IV bolus provides rapid peak plasma concentration; infusion allows controlled, sustained plasma levels.
67
Why is aseptic technique critical in parenteral administration?
To avoid introducing infections or pyrogens into sterile body compartments.
68
What are the risks of administering a non-isotonic or non-sterile IV solution?
Risks include phlebitis, haemolysis, embolism, or systemic infections.
69
What training is needed for parenteral administration?
Staff must be trained in aseptic technique, injection site selection, handling of needles/syringes, and emergency management (e.g. anaphylaxis).
70
Why might a patient with Crohn’s disease receive medications parenterally?
Because GI inflammation can impair drug absorption and bioavailability, making oral delivery ineffective.
71
A patient on chemotherapy is vomiting repeatedly. What route of administration should be considered and why?
IV or rectal — both avoid the need for swallowing and bypass the vomiting reflex.
72
What is the difference between topical and transdermal drug administration?
Topical aims for local action at the site of application (e.g. hydrocortisone cream for eczema).
Transdermal aims for systemic delivery via skin absorption (e.g. fentanyl patch).
73
When is intranasal drug delivery clinically useful?
Rapid systemic absorption via the rich vascular plexus in the nasal mucosa.
Used in emergencies (e.g. naloxone for opioid overdose, midazolam for seizures).
74
What are co-solvents and why are they important in injections?
Co-solvents like ethanol, PEG, or propylene glycol help dissolve poorly soluble drugs in injectable solutions.
Must be used with care due to potential for irritation or toxicity.
75
What are suspensions used for in parenteral formulations?
Depot injections (e.g. corticosteroids) where prolonged release is desired.
Require proper shaking before administration and must never be used intravenously.
76
What are the key requirements for ophthalmic formulations?
Sterile, isotonic, pH balanced, non-irritant.
Viscosity enhancers (e.g. hypromellose) often added to prolong contact time.
77
Why are otic preparations not interchangeable with ophthalmic ones?
Otic (ear) products are not necessarily sterile, whereas ophthalmic (eye) ones must be.
Never use otic products in the eye.
78
When is the vaginal route preferred and what are its features?
For local treatment (e.g. antifungals like clotrimazole) or hormonal therapy (e.g. oestrogen).
Avoids GI tract and can partially avoid first-pass effect.
79
What is meant by bioequivalence in relation to different dosage forms?
Two formulations are bioequivalent if they show similar rate and extent of absorption.
Critical when switching between generic and branded products — especially in narrow therapeutic index drugs like phenytoin.
80
What regulatory bodies oversee the safety of different routes of administration in the UK?
MHRA (Medicines and Healthcare products Regulatory Agency) ensures that medicines (regardless of route) are safe, effective, and properly labelled.
Also works with EMA for EU-linked data when relevant.
81
Which of the following statements about intravenous (IV) administration is TRUE?
A) It avoids the need for sterile formulation
B) It results in a delayed onset of action
C) It bypasses the first-pass metabolism
D) It is suitable for oily drug solutions
✅ Correct answer: C
💡 Explanation: IV administration delivers the drug directly into systemic circulation, bypassing absorption barriers and the liver's first-pass metabolism.
82
Which of the following routes is most appropriate for delivering a drug intended for rapid onset in a patient experiencing status epilepticus?
A) Oral
B) Rectal
C) Intravenous
D) Transdermal
✅ Correct answer: C
💡 Explanation: IV delivery ensures immediate therapeutic levels, critical in emergencies like status epilepticus.
83
Which route of administration avoids both the gastrointestinal tract and first-pass metabolism?
A) Oral
B) Sublingual
C) Rectal
D) Inhalation
✅ Correct answer: B
💡 Explanation: Sublingual delivery avoids the GI tract and first-pass metabolism via absorption through the oral mucosa.
84
A transdermal patch is MOST suitable when the drug:
A) Requires rapid onset
B) Is highly water-soluble
C) Needs frequent dosing
D) Has low dose and good lipophilicity
✅ Correct answer: D
💡 Explanation: Drugs suitable for transdermal delivery are typically potent, lipophilic, and require consistent plasma levels.
85
Which route would be most appropriate for delivering insulin?
A) Oral
B) Sublingual
C) Intramuscular
D) Subcutaneous
✅ Correct answer: D
💡 Explanation: Insulin is usually administered subcutaneously because it is degraded in the GI tract.
86
What is the main advantage of using a depot IM injection?
A) Rapid action
B) Avoids injection site pain
C) Sustained drug release over time
D) Enhanced liver metabolism
✅ Correct answer: C
💡 Explanation: Depot injections release the drug slowly, allowing prolonged therapeutic effect (e.g., antipsychotics)
87
Which of the following is a key requirement for ophthalmic solutions?
A) Must be hypertonic
B) Do not require sterility
C) Must be sterile and isotonic
D) Must contain alcohol for preservation
✅ Correct answer: C
💡 Explanation: Sterility and isotonicity are essential to avoid irritation or infection in the eye.
88
What is the PRIMARY reason rectal administration may be preferable to oral in some cases?
A) Faster onset than IV
B) Higher patient compliance
C) Partial avoidance of first-pass metabolism
D) No formulation limitations
✅ Correct answer: C
💡 Explanation: The rectal route partially avoids the portal circulation, bypassing first-pass metabolism.
89
Why is the intranasal route used for some emergency medications?
A) Poor absorption through the mucosa
B) Slower onset than oral
C) Non-invasive and rapid systemic absorption
D) Incomplete drug bioavailability
✅ Correct answer: C
💡 Explanation: The nasal mucosa is highly vascularised, allowing rapid absorption without needles.
90
A poorly water-soluble drug is best delivered parenterally using:
A) Aqueous IV injection
B) Sublingual tablet
C) Oil-based IM depot injection
D) Simple syrup solution
✅ Correct answer: C
💡 Explanation: Oil-based IM injections are suitable for lipophilic drugs requiring slow release.
91
Which of the following is an advantage of the sublingual route over oral administration?
A) Enhanced liver metabolism
B) Higher risk of degradation in saliva
C) Rapid onset due to mucosal absorption
D) Suitable for sustained release formulations
✅ Correct answer: C
💡 Explanation: Sublingual administration allows rapid systemic absorption, avoiding hepatic first-pass metabolism.
92
Which factor most limits the use of transdermal patches?
A) High water solubility of drugs
B) Variability in hepatic enzyme activity
C) Short half-life of the drug
D) Poor skin permeability of large molecules
✅ Correct answer: D
💡 Explanation: The skin is a strong barrier; only small, lipophilic, and potent drugs can pass effectively.
93
Buccal tablets differ from sublingual tablets because they:
A) Are swallowed for absorption
B) Are absorbed more rapidly
C) Provide prolonged release
D) Are suitable for high-dose drugs
✅ Correct answer: C
💡 Explanation: Buccal tablets dissolve more slowly, allowing prolonged drug absorption via the buccal mucosa.
94
In which of the following patients would the rectal route be particularly useful?
A) A conscious adult with phobia of tablets
B) A paediatric patient vomiting repeatedly
C) A patient requiring IV antibiotics
D) An elderly patient needing daily vitamins
✅ Correct answer: B
💡 Explanation: Rectal administration is useful when oral intake is not feasible, e.g. in vomiting children.
95
Why are oil-based formulations NOT suitable for IV administration?
A) They are highly irritant
B) They block hepatic clearance
C) They can cause embolism or occlusion
D) They require refrigeration
✅ Correct answer: C
💡 Explanation: Oil-based solutions can lead to fat emboli if injected intravenously — they are used IM only.
96
Inhalation is an ideal route for: (select the most appropriate)
A) Slow systemic delivery
B) Treating systemic bacterial infections
C) Localised drug delivery in asthma
D) Administering vaccines
✅ Correct answer: C
💡 Explanation: Inhalers deliver drugs directly to the lungs for local action in respiratory conditions.
97
A depot injection is preferred when:
A) A drug has a long half-life
B) A drug requires continuous plasma levels
C) A drug is highly water-soluble
D) Immediate effect is needed
✅ Correct answer: B
💡 Explanation: Depot injections release the drug slowly for consistent plasma levels over time.
98
Which property is most important for drugs used in transdermal patches?
A) High molecular weight
B) Rapid renal clearance
C) Lipid solubility
D) Acidic pKa
✅ Correct answer: C
💡 Explanation: Lipid solubility is crucial for drugs to penetrate the stratum corneum of the skin.
99
100
Which of the following statements is TRUE about parenteral administration?
A) It is less expensive and more convenient than oral
B) It includes the buccal and sublingual routes
C) It avoids the gastrointestinal tract
D) It has a slower onset than transdermal
✅ Correct answer: C
💡 Explanation: Parenteral routes like IV, IM, SC bypass the GI tract, useful for drugs unstable in the stomach.
101
A patient receives a suppository for pain relief. Which route is being used?
A) Intranasal
B) Rectal
C) Buccal
D) Vaginal
✅ Correct answer: B
💡 Explanation: Suppositories are solid dosage forms administered via the rectum.
102
Which route is MOST appropriate for a drug that is acid-labile and has extensive first-pass metabolism?
A) Oral
B) Intravenous
C) Topical
D) Inhalation
✅ Correct answer: B
💡 Explanation: IV administration bypasses the stomach and liver, suitable for unstable or extensively metabolised drugs.
103
Why is the oral route generally preferred in chronic conditions?
A) It ensures 100% bioavailability
B) It is the fastest route
C) It is safe, convenient, and patient-friendly
D) It avoids hepatic metabolism
✅ Correct answer: C
💡 Explanation: Oral dosing is non-invasive and convenient for long-term management.
104
Which of the following routes provides both local and systemic effects?
A) Sublingual
B) Inhalation
C) Intramuscular
D) Rectal
✅ Correct answer: B
💡 Explanation: Inhaled drugs can act locally in lungs (e.g. salbutamol) and systemically (e.g. anaesthetics).
105
What is a major disadvantage of oral administration?
A) Rapid onset
B) Cost
C) Inconvenience
D) Variable bioavailability
✅ Correct answer: D
💡 Explanation: Oral drugs may be affected by food, pH, enzymes, and liver metabolism, leading to variable bioavailability.
106
Which is NOT a parenteral route?
A) Subcutaneous
B) Intrathecal
C) Transdermal
D) Intravenous
✅ Correct answer: C
💡 Explanation: Transdermal is non-parenteral, as it involves absorption through skin rather than injection.
107
Which of the following routes is most likely to cause tissue irritation if the formulation is incorrect?
A) Oral
B) Intravenous
C) Inhalation
D) Buccal
✅ Correct answer: B
💡 Explanation: IV formulations must be isotonic, sterile, and non-irritant. Errors can cause severe reactions.
108
An intrathecal injection delivers the drug to which site?
A) Peritoneal cavity
B) Muscle
C) Cerebrospinal fluid
D) Epidural space
✅ Correct answer: C
💡 Explanation: Intrathecal delivery involves injecting into the CSF, often for anaesthesia or chemotherapy.
109
A major risk of the intramuscular route is:
A) Slow absorption
B) Needle phobia
C) Accidental IV administration
D) Skin irritation
✅ Correct answer: C
💡 Explanation: Poor injection technique may inadvertently introduce the drug into a vein, altering pharmacokinetics.
110
Which factor is least likely to influence oral drug bioavailability?
A) Gastric emptying rate
B) Hepatic enzyme activity
C) Drug lipophilicity
D) Injection technique
✅ Correct answer: D
💡 Explanation: Injection technique is irrelevant to oral administration.
111
Which route is typically used for contraceptive implants?
A) Intramuscular
B) Subcutaneous
C) Transdermal
D) Vaginal
✅ Correct answer: B
💡 Explanation: Subdermal implants are inserted SC and release hormones over months to years.
