L4: Drug absorption

Question 2

Why are there alternative injection routes besides oral delivery?

Answer 2

Because large molecules (e.g., proteins) cannot survive GI degradation and require direct delivery routes

Question 3

What are the main advantages of IV drug administration?

Answer 3

Fastest and most predictable route; allows high plasma concentrations; ideal for emergencies and precise dosing

Question 4

What determines peak tissue concentration in IV administration?

Answer 4

The rate of injection — fast bolus can cause dangerously high plasma levels

Question 5

How does steady IV infusion benefit drug administration?

Answer 5

Maintains therapeutic plasma levels while avoiding toxic peaks

Question 6

What drugs are commonly given IV in emergencies?

Answer 6

Lignocaine, propofol, diazepam — often used in status epilepticus

Question 7

What does subcutaneous and intramuscular absorption depend on?

Answer 7

Site of injection, local blood flow, and drug formulation

Question 8

What enzyme can be co-administered to enhance SC/IM absorption?

Answer 8

Hyaluronidase – breaks down extracellular matrix to improve drug diffusion

Question 9

What is an intrathecal injection?

Answer 9

Drug injection into the subarachnoid space via lumbar puncture, bypassing the BBB for CNS access

Question 10

Name five examples of intrathecal drugs.

Answer 10

Methotrexate, bupivacaine, baclofen, aminoglycosides, opiate analgesics

Question 11

What conditions can be treated with inhaled drug delivery?

Answer 11

Asthma, bronchitis, emphysema, lung cancer, respiratory infections

Question 12

Why is inhalation drug delivery advantageous?

Answer 12

Rapid onset, local lung action, bypasses first-pass metabolism, fewer systemic side effects

Question 13

How do inhaled drugs reach their site of action?

Answer 13

Via rapid absorption across mucous membranes of the respiratory tract and pulmonary epithelium

Question 14

What is asthma?

Answer 14

Chronic inflammatory airway disease involving swelling, mucus production, and bronchospasm

Question 15

What are common asthma symptoms?

Answer 15

Shortness of breath, wheezing, chest tightness, coughing, nighttime waking

Question 16

What are common indoor and outdoor asthma triggers?

Answer 16

Indoor: dust, smoke, pets, infections; Outdoor: pollen, pollution, exercise, temperature changes

Question 17

What is the first-line treatment for asthma?

Answer 17

Inhaled β2-agonists and glucocorticoids

Question 18

How do β2-agonists work in asthma?

Answer 18

Bind to β2-receptors on airway smooth muscle → ↑cAMP → bronchodilation

Question 19

List properties of β2-agonists.

Answer 19

Rapid onset (15–30 min), 4–6 hrs relief, minimal stimulation of β1/α receptors

Question 20

What do inhaled corticosteroids do in asthma?

Answer 20

Reduce airway inflammation, decrease immune cell activity, lower hyper-responsiveness

Question 21

Why are inhaled corticosteroids safer than oral ones?

Answer 21

Undergo first-pass metabolism, so only a small amount reaches systemic circulation

Question 22

What % of inhaled corticosteroid dose reaches airways?

Answer 22

Only 10–20%; majority deposited in mouth or pharynx and swallowed

Question 23

What is the role of spacers in inhaled drug delivery?

Answer 23

Break up particles, enhance lower airway delivery, improve coordination and reduce mouth/throat deposition

Question 24

Name common non-bronchodilator inhaled agents.

Answer 24

Sodium cromoglycate, nedocromil sodium (prophylactic anti-inflammatories)

Question 25

What is theophylline?

Answer 25

A bronchodilator with a narrow therapeutic window and significant drug interactions

Question 26

Why is prolonged-release inhalation formulation useful?

Answer 26

Extends duration of effect for drugs with short half-lives, reduces frequency of dosing

Question 27

How does liposome encapsulation help inhaled drug delivery?

Answer 27

Encapsulates both hydrophilic and lipophilic drugs → controlled release and uniform lung delivery

Question 28

How do surfactant-based inhalers improve therapy?

Answer 28

Combine drug with surfactants to slow release, prolong bronchodilation, and minimize side effects

Question 29

What is the role of biodegradable polymers in inhalation?

Answer 29

Form microcapsules for controlled sustained drug release by modulating degradation rate

Question 30

Which of the following is most likely to cause dangerously high plasma levels if injected too rapidly? A) Diazepam via IV bolus B) Baclofen via intrathecal injection C) Salbutamol via inhalation D) Sodium cromoglycate via spacer

Answer 30

A) Diazepam via IV bolus

Question 31

Why might a protein-based drug fail if given orally? A) It's highly lipid soluble B) It causes excessive inflammation C) It is degraded in the GI tract D) It undergoes enterohepatic recirculation

Answer 31

C) It is degraded in the GI tract

Question 32

Which technique enhances drug absorption from subcutaneous tissue? A) Combining with sodium bicarbonate B) Co-administration with hyaluronidase C) Inhalation via spacer D) Use of biodegradable polymers

Answer 32

B) Co-administration with hyaluronidase

Question 33

Why are inhaled corticosteroids safer than systemic ones? A) They directly stimulate β2 receptors B) They cause rapid CNS penetration C) They undergo first-pass metabolism D) They inhibit bronchodilation

Answer 33

C) They undergo first-pass metabolism

Question 34

A patient uses an MDI incorrectly and swallows most of the drug. What is the likely outcome? A) Increased therapeutic effect B) Bronchodilation within 15 mins C) Reduced efficacy and increased systemic side effects D) Enhanced drug delivery to lower lungs

Answer 34

C) Reduced efficacy and increased systemic side effects