ROA

Overview

A route of administration is the path by which a drug, fluid, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance is applied. While there are many used medically, the most common forms of ROA are oral, inhalation, injections, and, controversially, rectally. The choice of route is usually selected on a variety of factors, including:

• Bioavailability
• The form of the drug (liquid, powder, crystal, etc)
• Rate of absorption
• Desired effects (i.e. Certain drugs produce different results based on ROA)
• Convenience

Oral

Oral is generally seen as the most convenient and safest ROA. The limitation is in the fact that the liquids, capsules, tablets, or chewable tablets have to move through the digestive tract. When a drug is taken orally, food and other drugs in the digestive tract may affect how much of and how fast the drug is absorbed. Besides swallowing the dose may be administered through:

• Buccal (dissolving against the cheek membrane)
• Sublingual (dissolving under the tongue)
• Sublabial (dissolved under the lip)

Inhalation

Inhalation is known to be one of the faster and widely used ROA's. These typically involve the:

• Nasal passageways (insufflation) - The drug gets absorbed by the nasal membranes for rapidly doses to the brain. Repeated use can cause long term damage such as a deviated septum.
• Lungs- This is done through the form of vapor or smoke. This ROA is a bit hard to dose. Long term use can cause damage to the respiratory system.

Injections

This ROA is the most rapid, effective, and dangerous. The most popular injection routes are:

• Intravenious (injection into the vein) - Drugs used this way have a 100% bioavailability and are felt within 10-30 seconds. This is a very easy way to overdose. Long term use can lead to absesscess, vein damage, and tissue/muscle damage.
• Intramuscular (injection into the muscles) - Most drugs cannot be safely done this way. This allows for slower absorption and is often very painful.
• Intradermal (Also known as subcutaneous or skin-popping) - This method is for slow, steady absorption. This is often not a recommended ROA for most drugs.

Rectal

While largely stigmatized, A drug that is administered rectally will in general (depending on the drug) have a faster onset, higher bioavailability, shorter peak, and shorter duration than the oral route. Another advantage of administering a drug rectally, is that it tends to produce less nausea compared to the oral route and prevents any amount of the drug from being lost due to vomiting. In addition, the drug will reach the circulatory system with significantly less alteration and in greater concentrations. The bioavailability is usually second only to the IV ROA.

References and More Information

https://wiki.tripsit.me/wiki/Quick_Guide_to_Plugging

https://www.ncbi.nlm.nih.gov/mesh?term=Drug+Administration+Routes

https://www.merckmanuals.com/home/drugs/administration-and-kinetics-of-drugs/drug-administration