Pharmacology Chapter: Routes of Drug Administration

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Questions and Answers

Which dosage form can be used for both topical and systemic effects when administered rectally?

Syrup

Suppository (correct)

Enteric coated tablet

Effervescent tablet

What is a significant disadvantage of using the oral route for drug administration in severely ill patients?

It allows for easier dosage adjustments.

It produces higher bioavailability than other routes.

It can be administered without cooperation.

It often requires the patient to be alert. (correct)

Which benefit of the sublingual route enhances its use in emergency situations?

High bioavailability (correct)

Can be given rectally if needed

Ability to take larger doses

Slow onset of action

Which of the following routes prevents first-pass metabolism in the liver most effectively?

Sublingual route Signup and view all the answers

What is a common disadvantage associated with the rectal route of drug administration?

Patients often find it unacceptable Signup and view all the answers

Which of the following drugs is primarily unsuitable for the sublingual route?

Antibiotics Signup and view all the answers

Which dosage form allows for immediate dissolution in the stomach after oral administration?

Effervescent sachet Signup and view all the answers

What type of dosage form is NOT commonly used in oral administration?

Inhalation powder Signup and view all the answers

Which dosage form is specifically mentioned for single-dose administration?

Ampules Signup and view all the answers

What is a significant advantage of inhalational drug administration?

Avoidance of first-pass metabolism Signup and view all the answers

Which of the following is a disadvantage of using the inhalational route for drug administration?

Difficulty in dose adjustment Signup and view all the answers

Which method of parenteral injection is associated with the highest risk of spinal injury?

Intrathecal Signup and view all the answers

In what clinical scenario would the intraarticular injection of corticosteroids be most appropriate?

Localized joint inflammation Signup and view all the answers

Which route is most suitable for achieving a rapid systemic effect with drugs that vaporize easily?

Inhalational route Signup and view all the answers

Which parenteral injection technique involves injecting directly into the spinal canal?

Intrathecal Signup and view all the answers

What is a key disadvantage associated with the use of inhalational route in drug delivery?

Not suitable for irritant drugs Signup and view all the answers

Which of the following is NOT an enteral route of drug administration?

Inhalation Signup and view all the answers

What is a significant disadvantage of the oral route of drug administration?

Delayed onset of action. Signup and view all the answers

Which drugs are most affected by first-pass metabolism?

Orally administered drugs Signup and view all the answers

What is a primary advantage of sublingual administration?

It bypasses first-pass metabolism. Signup and view all the answers

What effect does enteric coating have on a drug?

Protects the drug from gastrointestinal fluids. Signup and view all the answers

Which of the following routes provides partial first-pass metabolism effects?

Rectal Signup and view all the answers

What limits the usefulness of orally administered drugs in emergency situations?

Slow absorption leading to a delayed onset of action. Signup and view all the answers

Why are drugs like lidocaine and insulin not recommended for oral administration?

They undergo extensive first-pass metabolism. Signup and view all the answers

Study Notes

Routes of Drug Administration

Presented by Dr. Mariam Ashraf Amin, Pharmacology and Toxicology department, Faculty of Pharmacy (2024-2025)
Drug administration has two main categories: enteral and parenteral.

Enteral Routes

Enteral routes are related to the gastrointestinal tract (GIT).
This includes: oral, sublingual, buccal, and rectal administration.

Oral Route

Advantages: easy, economical, self-administered, and safe due to potential for overdose management.
Disadvantages: slow absorption (limiting in emergencies), destruction by digestive fluids, interactions with food, and unsuitable for unconscious/uncooperative/severely ill patients or if vomiting/convulsions occur.
Dosage forms: oral drops, suspension, tablets, effervescent sachets (enterically coated, sustained release), colored, effervescent, chewing tablets, and lozenges.

Sublingual Route

Advantages: rapid onset, suitable for emergencies (angina/hypertension), bypasses first-pass metabolism (high bioavailability), and excess dose can be expelled.
Disadvantages: not suitable for all drugs (e.g., nitrates/captopril).

Rectal Route

Advantages: suitable for patients unable to take oral drugs (e.g., unconscious/vomiting). 50% of drug bypasses the liver, offers localized or systemic effects (depending on drug), and avoids gastric irritation.
Disadvantages: not suitable for diarrhea, inconvenient/unacceptable by many patients.
Dosage forms: suppositories and enemas.

Parenteral Routes

Parenteral routes bypass the GIT, involving injections, topical application, and inhalation.

Injections

Advantages and Disadvantages of different types of injection are discussed (Intravenous (IV), Intramuscular (IM), Subcutaneous (SC), and Intrathecal)
IV: rapid onset, suitable for emergencies, maintains drug in active form, and high bioavailability. Disadvantages include expense, aseptic conditions are needed, difficulty in self-administration, pain, need for patent vein, and difficulty eliminating the drug if toxicity occurs.
IM: suitable for moderate-volume drugs and irritant drugs. Disadvantages include not suitable for anticoagulants, lower volume given (4-5 ml), expense, need aseptic condition, and pain.
SC: suitable for suspensions and oily solutions, provides slow duration of action, suitable for hormones. Disadvantages include slow onset, not suitable for irritant/large volumes.
Intrathecal/Intra-thecal: high concentration in CSF suitable for treating CNS disorders, diagnosing CNS disorders and injecting antibiotics. Need highly specialized physician and special precaution for avoiding infection/spinal nerve injury.

Inhalational Routes

Advantages: suitable for volatile compounds (gases), allows for local/systemic effects, avoids first-pass metabolism, rapid onset (similar to IV) and self-administered.
Disadvantages: not used for irritant drugs, difficult to adjust dose, and may need special inhaler apparatus.
Used for bronchial asthma and volatile anesthetics.

Topical/Local Administration

Advantages: local high concentrations of drug, bypasses first-pass metabolism (transdermal), localized effects.
Disadvantages: some systemic absorption can occur; unsuitable for highly lipid-soluble drugs.
Dosage forms: drops, creams, ointments, lotions, transdermal patches.

First-Pass Metabolism

Metabolism that occurs as drugs are absorbed from the Gastrointestinal tract before reaching systemic circulation.
Hepatic first-pass: Drugs absorbed from the GIT are carried first in portal circulation to the liver.
Intestinal first-pass: due to intestinal mucosal metabolism affecting drugs e.g., nitroglycerin, propranolol, isoprenaline, and tyramine.
First-pass metabolism can be avoided or reduced by sublingual, parenteral, or partially by rectal administration.

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Description

Explore the different routes of drug administration in pharmacology, focusing on enteral and parenteral methods. This quiz covers various aspects, including advantages and disadvantages of oral, sublingual, buccal, and rectal routes, along with dosage forms related to each method. Enhance your understanding of drug delivery systems essential for effective pharmacological treatments.