Why do we have to take some drugs differently?


I often wonder why there are different ways of taking drugs: Most people have to swallow the drugs whilst others are asked to insert it in their anus or inject it at their buttocks. Intriguing, right? If you have the same opinion, journey with me as we explore the different methods of drug administration and the reasons behind them.


A drug is a chemical substance that is taken to produce a biological effect. Drugs are given to treat a symptom, cure a disease or prevent a symptom. Drugs are very important yet dangerous. Knowing when and how to take a certain drug can save a life or cause the death of a person. There are different ways to take a drug which is affected by factors such as:

· Convenience: How easy it is to take the drug. Is the drug common?

· The state of the patient: Is the patient awake or sleeping?

· The willingness of the patient: Is the patient ready to take the drugs on their own and comply or will they need help?

· The age of the patient

Most importantly drugs have are taken differently based on these main factors:

· The part of the body being treated: Is the drug needed at only one region or even throughout the entire body?

· The way the drugs work in  the body: Some drugs work quickly whilst others take time. Some drugs are affected by the pH and enzymes in the body so they have to be given such that they escape most of them.

· The nature of the drug:  The physical state of the drug. A solid drug may either be swallowed whilst a gaseous one may be inhaled.

Based on the action of the drug, drugs routes are grouped into two: local and systemic. Local means that the drugs are taken to affect one particular part or region of the body whilst systemic means they pass through more than one part of the body.‌‌

Local routes

The local route is also referred to as the topical route. This type of drug administration usually affects body surfaces such as the skin and mucous surfaces of the eye, nose, ear, mouth, vagina, etc. The intention is to provide relief to these local areas. They come in forms such as creams, ointments, drops, etc. They are usually high in concentration because they stay in one place. Sometimes, they escape to other parts of the body but the majority remains at the local site. Below are some examples.

1. Mouth inhalation- drops.

2. Nose- nasal drops.

3. Eyes- eye drops.

4. Skin surfaces- ointments, creams, etc.

Pros of local/topical routes

· It is easy to apply and convenient. Almost anyone can take this type of drug at home without the help of a professional.

· Drugs work at the desired origin and fast because they are delivered specifically to a site.

· The drugs avoid the risk of being degraded by enzymes and other substances in the body.


· There may be an allergic reaction especially on the skin where the drug was applied.

· Most drugs cannot use this process due to their structure and chemical properties.

Systemic routes

Systemic routes involve drugs that do not affect just one part of the body but go through at least more than one body part. The two main divisions are the enteral and parenteral routes. The enteral route deals with drugs that pass through the alimentary canal (gut) such as the mouth whilst parenteral routes deal with those that do not pass through the alimentary canal which includes injections, inhalations, etc.

1. Enteral route

· Oral

Taking drugs orally is the most common form of drug administration because it is usually easy and less expensive. The drugs are placed in the mouth and swallowed. They pass through the stomach and are absorbed into circulation just like food. Because the stomach contains acids and digestive enzymes, these drugs are manufactured to withstand the conditions of the stomach and the alimentary canal. They have to be able to permeate the lining in the gut. Drugs that are taken orally include tablets/pills, capsules, solutions, syrups, emulsions and solutions.


i. It is the simplest, most common way of taking drugs.

ii. Almost everyone can take drugs using this approach.

iii. It is painless as compared to other routes such as injection.

iv. It is less expensive, as compared to the others.


i. Drugs take time to work.

ii. It is not suitable for people who are unconscious and need immediate relief or treatment.

· Buccal/ Sublingual

Unlike oral drugs which are swallowed, this type stays in the mouth only. Patients are asked to keep the drug under the tongue (sublingual) or between the gums and lining of the cheeks (buccal). As mentioned earlier, patients are advised not to swallow the drugs. The drug dissolves and is absorbed into the blood vessels in the mouth. It goes through the liver first and is later sent to other parts of the body. The drugs are not swallowed because the acid and enzymes in the stomach will inactivate them.


i. It is easy to take such drugs or medications.

ii. It is convenient for people who have difficulty swallowing.

iii. Effect of the drug is achieved quickly.


i. It is inconvenient for drugs that are bitter since drugs must not be swallowed.

ii. Drugs should be small else patients might spit them out.

· Rectal

Drugs of this type are usually solids (suppository form) or liquids. These type of drugs are injected from the anal region to the rectum. They are quickly absorbed into the bloodstream than oral drugs.


i. It is good for patients who are constantly vomiting their drugs.

ii. It escapes the harsh conditions in the stomach.

iii. Drugs are absorbed quickly so the effect is seen quickly.


i. The patient might interrupt the process especially when the drug is irritant.

ii. Some microorganisms at the rectum can slow the process or reduce the potency of the drug.

2. Parenteral routes

· Injections

Injections are the second most common form of drug administration. Injections are usually given when drugs are in solutions or suspensions at various body parts using a needle and a syringe. There are different routes of injection sites. Below are a few.

a) Intra-venous- the drug is introduced directly into a vein which is sent to the heart to be pumped to the rest of the body. It is the quickest way for a drug to reach the body. It may be given during emergencies or usually for infusions (drips) especially when a patient is admitted to a hospital.

b) Intra-muscular- these are delivered directly into the muscles. The muscles contain a greater amount of blood vessels so the absorption is higher and the effect is soon. Injection sites involve the buttocks, the thighs or the upper arm. An example is the hepatitis A, B and Covid-19 vaccine administration.


i. Drug absorption is really fast.


ii. It is painful.

iii. There may be swelling at the site of injection.

· Inhalations

· Transdermal: It involves both intra-dermal and subcutaneous routes of administration. The upper part of the skin is called the epidermis, beneath it is the dermis. Intra-dermal involves an injection into the dermis whilst sub-cutaneous is injection below the dermis. An example is the BCG vaccine and measles vaccine which is given to children at birth to treat tuberculosis intra-dermally and measles sub-cutaneous form respectively.

Drugs can save life or cause death. Knowing when or how to take drugs can save a life today. The next time you are given a medication, I hope you appreciate why and how the drug is going to work.


  1. Routes of administration. Retrieved from https://www.pharmapproach.com/routes-of-drug-administration/
  2. Routes of administration. Retrieved from https://www.medindia.net/patientinfo/routes-of-drug-administration.htm#introduction-on-routes-of-drug-administration


A young lady who is excited to influence the society and world with the knowledge she has acquired.