Routes of Poison Administration

Question: Considering mode of administration, poison acts more rapidly when:

(A) Inhaled in gaseous state

(B) Injected intramuscularly

(C) Injected subcutaneously

(D) Applied to skin

Answer: (A) Inhaled in gaseous state


The route of administration is the path taken or administered by a drug, toxin, or poison into a person’s body, as distinguished by the site where any drug is applied. It is generally classified according to its target:

Not every path is equally effective. The following are the fastest to slowest pathways:

Intravenous (into a vein) injection > inhalation > intraperitoneal (into the body) injection > intramuscular (into the muscle) injection> ingestion > topical (onto the skin) absorption

Some poisons, no matter how they are administered, do not have a quick effect.

The concentration of poison in the body might build up over time, redistribute, or exceed repair and elimination mechanisms.


Once in the body, the poison must overcome or bypass the body’s natural defences and translocate to the place where it will act.

When a toxin is ingested, it is in gas form and travels through the body as absorbed gases through the alveoli via the bloodstream.

When poison is consumed, it is absorbed through the GI tract and small intestine.

When absorbed through the skin, the toxin first enters the pores, then the subcutaneous tissues, and lastly the bloodstream.

Routes of administration can be classified into two categories:

• Enteral routes/gastrointestinal routes.

• Parenteral routes.

Enteral routes

An enteral route is one in which the medicine is delivered through the gastrointestinal tract. It is available in both oral and rectal forms. Sublingual and sublabial pathways are also included. It is a relatively slower mode of action for medication absorption.

Oral route: Absorption often occurs in the tongue and gums of the oral tract.

Absorption is greatly influenced by the sublingual and supralingual pathways. Sublingual absorption is faster since the toxin is converted directly to the heart, although it takes longer.

Rectal route: Drugs can be administered via anus and absorbed directly into the bloodstream via the mucosal membrane. Because the rectum is so sensitive, this administration may induce tissue burning or bleeding.

Read More: Source of Poison

Parenteral Route

The Parenteral route encompasses all other routes that do not involve the gastrointestinal tract. It affects the body on a systemic level. It has the following administration categories:

Intradermal: Drugs are administered from the skin’s surface in this case. This type of poisoning is especially common in cases of chronic poisoning.

Intravenous: It is one of the quickest forms of drug delivery since the injection is given immediately and the drug is transported directly into the veins, where it is swiftly circulated into the blood. This type of medicine could result in instant death.

Intraosseous: This method includes injecting a medication directly into the bone marrow. This modality is actually utilised for the medicinal administration of medications.

Intra-arterial: This procedure includes injecting a medication straight into the artery. It is a quick method of administration.

Intramuscular: The medicine or poison is injected into the muscle of the thigh, upper arm, or buttock in this manner. This mode requires more time than other parental settings.

Subcutaneous: The medicine is injected into the layer beneath the skin, known as the subcutaneous layer, in this manner. The medication subsequently enters the bloodstream via small blood vessels. This technique is mostly utilised for protein medications that would be degraded if supplied via the gastrointestinal tract.

Inhalation: Poison inhalation is caused by chemical absorption through the respiratory tract (lungs). Once poison enter the respiratory system, they can be absorbed into the bloodstream and distributed throughout the body. Poison can be ingested as vapours, fumes, mists, aerosols, or fine dust.

The nose is the principal channel in this phase. The nasal aperture is particularly absorptive due to the presence of mucous membrane. Poison microparticles are easily absorbed and rapidly transferred to the lungs. They are circulated into the blood from the lungs.

Read Also: Classification of Poison