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Ever popped a pill and wondered how it actually knows where to go and what to do? Or maybe you’ve seen someone get an injection and thought about why that method was chosen? It’s pretty fascinating, actually. The way a medicine gets into your body isn’t just a random choice; it’s a carefully considered decision that hugely impacts how well the drug works and how safe it is.
This process, known as drug administration, involves various “routes” – basically, the different pathways drugs take to get inside us.
Routes of Drug Administration
When we take any medicine, it needs to enter our body and reach the right place to work effectively. The way a drug is introduced into our body is called the route of drug administration. Choosing the right route is very important, as it affects how quickly the medicine acts, how effective it is, and how long it stays in the body.
In this blog, we’ll break down the different types of drug administration routes in a simple and clear way. Whether you’re a pharmacy student or just someone curious about how medicines work, this guide will help you understand the basics.
Oral Route
This is the most common route for taking medicines. Most people are familiar with this method.
How its works
You swallow the medicine, usually as a tablet, capsule, syrup, or powder. It then goes to your stomach, where it begins to dissolve. From there, the drug is absorbed in the small intestine and enters the bloodstream. Once in the blood, it travels to the site where it is needed.
Examples
- Tablets
- syrups
- Oral Liquid Solutions
Advantage of Oral Route
- Easy to take, especially for long-term treatment
- Painless and safe
- Cost-effective and does not need medical help
Disadvantage of Oral Route
- Slow onset of action (because it needs to be digested first).
- Not suitable for patients who are vomiting or unconscious.
- Some drugs can be destroyed by stomach acids or liver enzymes before reaching the bloodstream (called first-pass metabolism)
Sublingual Route (Under the Tongue)
In this method, the medicine is placed under the tongue and left to dissolve.
How it Works
The area under the tongue has many blood vessels. When the drug dissolves there, it is absorbed directly into the bloodstream without going through the stomach or liver. This means the drug acts quickly.
Examples
- Nitroglycerin tablets (used in chest pain or angina)
Advantage of Sublingual Route
- Very fast action, useful in emergencies.
- Avoids destruction by stomach acid and liver metabolism.
- Easy to use
Disadvantage of Sublingual Route
- Not suitable for all drugs.
- Some patients may find the taste unpleasant or have irritation
Buccal Route (Inside the Cheek)
Here, the medicine is placed between the gum and the inner cheek and allowed to dissolve slowly.
How it Works
Like the sublingual route, the buccal area also has rich blood supply. The drug slowly enters the bloodstream through the mucous membrane of the mouth.
Examples
- Certain hormone tablets, like testosterone or buccal forms of certain painkillers
Advantage of Buccal Route
- Avoids digestive system and liver breakdown.
- Provides longer-lasting effects compared to sublingual route
Disadvantage of Buccal Route
- Limited number of drugs can be given this way.
- Drug may be accidentally swallowed.
Rectal Route (Through the Rectum)
In this method, the drug is given through the rectum using suppositories, enemas, or rectal gels.
How it Works
The medicine dissolves in the rectum and is absorbed through the rectal lining into the bloodstream. This route is useful when oral administration is not possible.
Examples
- Paracetamol suppository (used for fever in children).
- Glycerin suppository (used for constipation).
- Diazepam rectal gel (used in seizures)
Advantage of Rectal Route
- Useful for unconscious or vomiting patients.
- Bypasses stomach acid and liver metabolism.
- Can be used for both local and systemic action.
Disadvantage of Rectal Route
- Some people may feel uncomfortable or embarrassed.
- Absorption may be irregular and slower compared to other methods.
Topical Route (Skin or Mucous Membrane)
This involves applying the drug directly on the skin or to specific areas like the eyes, nose, or ears.
How it Works
The drug acts at the site of application. In some cases, a small amount may get absorbed into the blood, but the main effect is local (at the site where applied).
Examples
- Antiseptic creams for wounds
- Eye drops for infections or dryness
- Nasal sprays for cold or allergies
Advantage of Topical Route
- Acts directly where needed
- Fewer side effects compared to oral or injectable routes
- Easy to use and generally safe
Disadvantage of Topical Route
- Not suitable for deep or internal conditions
- May cause skin irritation or allergic reactions in some cases
Transdermal Route (Via Skin Patch)
In this route, a special patch containing medicine is applied to the skin.
How it Works
The medicine in the patch slowly passes through the skin into the bloodstream. It provides continuous and controlled release of the drug for several hours or even days.
Examples
- Nicotine patches (for people trying to quit smoking)
- Hormone patches (used in hormone replacement therapy)
Advantage of Transdermal Route
- Steady and long-term drug delivery
- Convenient (just stick it on)
Avoids stomach and liver breakdown
Disadvantage of Transdermal Route
- Not all drugs can be given this way
- Can cause local skin irritation
- Slower onset of action
Inhalation Route (Through the Nose or Mouth)
Drugs are breathed in using inhalers, nebulizers, or sprays.
How it Works
The drug reaches the lungs and is absorbed through the lung tissues into the bloodstream. It can also act locally in the lungs.
Examples
- Inhalers for asthma (e.g., Salbutamol)
- Nebulized antibiotics or steroids
- Anesthetic gases (used during surgery)
Advantage of Inhalation Route
- Very fast action (lungs absorb drugs quickly)
- Ideal for treating respiratory diseases
- Smaller dose needed, reducing side effects
Disadvantage of Inhalation Route
- Requires correct technique for inhaler use
- Some drugs may irritate the respiratory tract
- Equipment like nebulizers may be expensive
Parenteral Route (By Injection)
This route involves giving drugs using a needle and syringe. It’s used when fast action is needed, or when the patient cannot take medicines orally.
Types of Parenteral Injections:
Intravenous (IV) – Directly into the vein
- Very fast action
- Used in emergency cases like heart attack or severe infections
- Example: IV antibiotics, IV fluids
Intramuscular (IM) – Into the muscle
- Slower than IV but lasts longer
- Commonly used for vaccines and painkillers
- Example: Tetanus injection
Subcutaneous (SC) – Under the skin
- Absorption is slower and steady
- Used for drugs that need to be given daily or regularly
- Example: Insulin for diabetes
Advantage of Parenteral Route
- Useful in emergencies
- Accurate dose reaches the bloodstream
- No effect of stomach or liver enzymes
Disadvantage of Parenteral Route
- Pain at injection site
- Requires trained person and sterile equipment
- May cause infection or bleeding if not done properly
