Pharm Basics, part 5: Routes of Administration: Oral, NG/G-tube, Sublingual, Transdermal, Inhalation, Optic, Otic

by Cathy Parkes August 13, 2021 Updated: February 23, 2022 15 min read

In this article, we’ll discuss the routes of medication administration and best practices for each route. A route of administration refers to one of the many ways a patient's medication is administered. Routes include oral, nasogastric tube/G-tube, sublingual, transdermal, inhalation therapy, optic, and otic medication administration. We’ll cover each one below.

This series follows along with our Pharmacology Basics and Safe Medication Administration Flashcards for Nursing Students which are intended to help RN and PN nursing students build a strong foundation going into Pharmacology and as preparation for the ATI, HESI, and NCLEX.

Routes of administration are how nurses administer a patient's medication, literally the route the medication takes from its container into the patient’s body. A route of medication administration defines where a drug is applied, for example, orally (in the mouth) or intravenously (via an I.V.).

The choice of which route of administration to use depends not only on the convenience of a particular route, it also depends on the drug’s properties and pharmacokinetics. Pharmacokinetics is the study of the movement and processing of drugs within the body.

Below, we will discuss the following (seven) routes of administration:

  • Oral
  • NG and G-tube (nasogastric tube and gastrostomy tube): a nasogastric (NG) tube is a tube that is placed through the nose into the stomach; a gastrostomy tube is an enteral feeding device placed endoscopically, radiologically, or surgically with its tip in the patient's stomach ("enteral" means passing directly through the intestine; "endoscopic" is when the provider inserts a tool called an endoscope, usually a thin plastic tube, into a person’s body)
  • Sublingual: medication that dissolves under the tongue
  • Transdermal: the application of a medicine or drug through the skin
  • Inhalation therapy: medication dispersed via an aerosol spray, mist, or powder that patients inhale into their airways
  • Optic: medication administered in the eye (eye drops)
  • Otic: medication administered in or to the outside of the ear

Oral medication administration

Oral medication administration is the process by which drugs are delivered by mouth through the alimentary tract. The alimentary tract comprises the organs that food and liquids travel through when they are swallowed, digested, absorbed, and exit the body.

The kinds of drugs most often administered orally include: liquids, capsules, tablets, and chewable tablets.

How to administer an oral medication

Here are the key points for administering oral medications to your patient.

Upright seated position

When administering an oral medication, sit the patient in an upright seated position, such as a high Fowler's position. In the high Fowler's position, the patient is usually seated upright with their spine straight. Their upper body is between 60 degrees and 90 degrees and their legs may be straight or bent.

Mix with food

Certain medications, usually regular tablets, can be crushed and mixed with a small amount of food, for example applesauce or pudding. Do not mix the medications with a large amount of food, because if the patient decides they don't want any more of the food that the medication is mixed into, they will not get the full dose of the medication.

Enteric-coated or extended-release medications

Do not crush enteric-coated or extended-release medications when you administer them. An enteric-coated drug is designed to keep its active ingredient from releasing until it has passed through the stomach and into the small intestine. These medications are also known as "slow release" — they are intended to dissolve in the patient's intestines and not their stomach because of the harmful effect these substances can have on the stomach.

Liquid medications

When measuring a dose of a liquid medication, you are most likely pouring the dose into a container. To ensure you measure out the correct dose, first observe the meniscus of the liquid. A liquid's meniscus is the upward (convex) or downward (concave) curve of the surface of the liquid as it sits in the container. Make sure that the lowest point of the meniscus is at the ordered dose level.

Contraindications for administering an oral medication

A contraindication is a specific situation in which a drug, procedure, or surgery should not be used because it may be harmful to the patient.

When administering oral medications, the following are contraindications and require an alternative method of medication administration:

  • Decreased level of consciousness
  • Lack of a gag reflex
  • Difficulty swallowing (dysphagia)
  • Vomiting
  • Connection to NG (nasogastric) suctioning

In any of these cases, oral medications would be contraindicated for that patient.

Nasogastric (NG) and G-tube medication administration

Another route of medical administration is via a nasogastric (NG) or gastrostomic tube. As noted above, an NG tube is a tube that is placed through the nose into the stomach. “Naso” is the medical term for nose, and “gastric” means stomach, so administering medication through a nasogastric tube is when a tube is inserted through the patient’s nostrils, passes through the posterior pharynx and down the esophagus, and into the stomach. Nasogastric tubes can be used to deliver (liquid) medications to a patient.

A gastrostomy tube (or G-tube) is an enteral (directly inserted into the intestines) feeding device placed endoscopically, radiologically, or surgically with its tip in the patient's stomach. Medications may be delivered into the patient through a G-tube.

X-ray confirmation of correct placement of the NG or G-tube

Once it has been inserted, and before any medications are administered via an NG or G-tube, confirm that the placement of the tube is correct. The first time this confirmation is made, it is done by taking an X-ray, allowing you to see the tube and its placement within the patient.

pH testing to confirm the correct placement of the NG or G-tube

Once the position of the nasogastric or gastrostomic tube has been confirmed via X-ray, subsequent confirmations that the tube is still correctly placed must be made. These subsequent confirmations may be made using gastric pH testing. Using a sample of gastric fluid (the fluid from the stomach), check the pH. A pH of 5.5 is recommended to confirm the correct placement of an NG or G-tube. Correct placement of the tube is important because this will reduce the risk of potentially fatal aspiration.

Use liquid medications if possible

When administering medications via an NG or G-tube route, it is best to use liquid forms of medications. If it is not possible to use a liquid form of the medication, crush a tablet version of the medication into 15 - 30 mL of sterile water and administer via the NG or G-tube. Make sure you are using sterile water and not normal saline, as saline may alter the effectiveness of the medication.

As mentioned above, never use crushed enteric-coated or extended-release capsules in an NG or G-tube medical administration route, because they are intended to be slow-release and dissolve in the patient's intestines and not their stomach.

Flush the line

Before and after medication administration, flush with 30mL of sterile water. This cleans the line before its next use.

Administer multiple medications separately

When administering more than one medication, administer each medication separately and flush the line with sterile water both before and after each medication.

Sublingual and buccal medication administration

Two routes of administration closely related to each other are sublingual and buccal.

Sublingual medication administration is when medication is placed under the tongue to be dissolved and absorbed into the bloodstream through the tissue. Literally "sub" (under) and "lingual" (tongue).

Buccal medication is absorbed in a similar way — it is also administered in the mouth to be absorbed into the bloodstream, but in this case the medicine is placed in the space between the inside of the cheek and the teeth, also known as the "buccal cavity."

Administer after oral medications

Administer sublingual and buccal medications after you have administered a patient's oral medications. That is because these medications need time to fully dissolve in the mouth. If a patient mistakes these medications for regular oral medications, they might swallow them, potentially administering too big a dose in the incorrect manner (these medications are supposed to be absorbed into the bloodstream, not digested in the stomach).

Avoid eating or drinking

Similarly, it is also important that the patient does not eat or drink anything until the medications have completely dissolved. This is to ensure proper drug absorption; if the patient eats or drinks anything before the medications are completely dissolved, they might swallow them, negating their effectiveness and potentially causing harm.

Transdermal medication administration

Transdermal medication administration is another route of medication administration. Transdermal drugs deliver medication through the skin, for example, via a patch. For example, hormonal contraceptives are available in a transdermal patch.

Transdermal drug delivery relies on the ability of the drug to pass through the skin into the systemic circulation.

These medications have become increasingly popular because of their particular advantages, for example, bypassing the first-pass metabolism of the liver (associated with the oral route), thus protecting the liver from damage. Transdermal medications also decrease the risk of damage to the gastrointestinal system (also suffered by using the oral route). Their ease, efficacy, and painlessness increase the likelihood of consistent patient use. This in turn allows for consistent and stable drug administration (ensuring regular use).

How to administer transdermal medications

Choose a spot on the upper body or upper arms to apply a patch. Do not apply the patch to the arms below the elbows, to the legs below the knees, or to skin folds. Apply the medication to a clean, dry, hairless area of skin that is not irritated, scarred, burned, broken, or calloused. When changing patches, choose a different area for the new patch.

Disinfection/preparation of the area

Always start by properly disinfecting and cleaning the skin where the medication is to be applied.

Wear gloves

Wear gloves when applying transdermal medications. This prevents accidentally absorbing any of the medication through your own skin.

Do not cut transdermal patches

Do not cut a transdermal patch because cutting a patch could result in the medication being released all at once. This could cause serious harm to the patient, including death from overdose.

Removing and reapplying transdermal medications

To remove and reapply a transdermal patch, peel off the old dose, fold it in half (sticky sides together), and dispose of it properly, as the used patch might still have active medicine on its surface. As noted above, rotate sites for patches and apply the new patch in a clean, hairless, dry area of the body. Finally, label the new patch with date, time, and initials.

Inhalation therapy

Another route of medical administration is inhalation therapy. This is when medication is dispersed via an aerosol spray, mist, or powder that patients inhale. This route of administration allows the conveying of the medication directly into the airways.

The patient holds an inhalation therapy device between their lips and activates it to dispense the medication. Different devices require different techniques to administer the medication properly.

To ensure high bronchial deposition of the drug, all inhaler-type devices should deliver a high proportion of fine particles, be easy to use, and provide constant and accurate doses of the active substance. Nebulizers are easy to use, which makes them more patient-friendly, but they do not provide constant or accurate doses of medication, which may have a negative impact on their effectiveness.

Among the most widely used types of inhalers are metered-dose inhalers or MDIs (also known as pressurized metered-dose inhalers, or pMDIs) and dry powder inhalers (DPIs).

Below, we explain how to use MDIs and DPIs to administer medications and differentiate between the two.

Metered-dose inhaler (MDI)

An MDI is a pressurized canister of medicine in a plastic holder with a mouthpiece. When sprayed, it gives a reliable, consistent dose of medication.

How to use an MDI correctly

First, the patient should shake their inhaler and, if applicable, attach a spacer. A spacer is a device that attaches to the MDI and helps deliver the medicine to the airways of the lungs instead of into the mouth. This helps the medicine work better and lessens possible side effects.

Next, the patient should take a deep breath and exhale.

Next, they place the MDI between their lips and press down on the inhaler as they take a slow, deep breath that lasts at least 3 to 5 seconds.

The patient should then hold their breath for 10 seconds, after which they may remove the inhaler from their mouth and slowly exhale.

If the patient is using a glucocorticoid inhaler (a glucocorticoid is a class of corticosteroid), it's important that the patient rinse their mouth after administration to prevent a fungal infection in the mouth.

Dry powder inhaler (DPI)

Like MDIs, DPIs deliver medication into the lungs. Unlike the pressurized MDI, DPIs don’t push the medication into the patient's lungs. The patient has to breathe in strong and steady to get the medicine.

How to use a DPI correctly

There are a few key differences between a DPI and an MDI. Do not shake a DPI device, nor is there the need to attach a spacer.

Instead of taking a long, slow inhale, the patient should breathe in rapidly and deeply for only 1 to 2 seconds. A long inhalation risks the powdered medication combining with the moisture in the patient's mouth, which could clog or otherwise impair the device.

Optic medication administration

Optic medications are another route of medication administration and refer to drugs specifically for the eyes. These drugs can be used to diagnose, treat, and prevent eye diseases. The most common therapeutic uses for eye medications include glaucoma (an eye disorder that results in increased pressure inside the eyeball), eye infections, allergies, and inflammation (redness) of the eye.

How to administer optical medications

Wash hands and shake the container. Then have the patient look up.

With the non-dominant hand, gently lower the patient's lid to expose the conjunctival sac. This is the clear moist membrane that covers the inner surfaces of the eyelids and the front of the eyeball. The dominant hand is used to hold the container because it is more steady for aiming the droplets.

Drop the medication into the conjunctival sac without touching the tip of the applicator to the eye. This is to keep the dropper free from bacteria, which can then be easily transferred into the patient’s eye the next time the dropper is used.

After administering the drops, apply gentle pressure to the nasolacrimal duct, also known as the tear duct, for approximately one minute. This is to help prevent systemic absorption of powerful drugs, for example, those used to treat glaucoma. Applying pressure to the duct (holding a finger over it), also prevents the medication from entering the tear duct and draining away.

If the patient has been ordered to receive multiple eye drops, wait approximately five minutes between applications of the next set of drops.

Otic medication administration

The last route of medication administration in this article concerns otic administration. Otic medications are applied to, or into, the ear to treat conditions of the external and middle (inner) ear. These drugs are used to treat dermatitis of the ear (itching, scaling, flaking, and swelling of the skin of the ear canal and skin at the entrance of the ear canal), wax buildup, and ear infections.

How to administer otic medications

Ensure ear drops are at room temperature before administration.

Have the patient lay on their unaffected side so that the affected side is up.

Pull the pinna (the "outside" of the ear) up and back for adults and down and back for children under three years of age. An easy way to remember this difference is adults will be taller, so they're up higher, hence pull up and back. Children, on the other hand, are shorter, so they'll be down lower, so for them, pull down and back.

To administer the drops, hold the dropper approximately one centimeter above the ear canal.

After the drops are instilled, apply gentle pressure to the tragus (the small protrusion of skin-covered cartilage situated in front of the ear canal).

The patient should remain on their side for about one to two minutes to allow the medication to seep into the ear and be absorbed.


Full Transcript

Hi, I'm Cathy with Level Up RN. In this video, I am going to start talking about routes of medication administration and best practices for each route. The routes I'll be covering in this particular video include the oral route, NG and G tube, sublingual, transdermal, inhalation therapy, optic, and otic medication administration. So let's start with oral medication administration. There are some contraindications for a patient receiving their medications orally, for example, if they have a decreased level of consciousness, if they lack a gag reflex, if they have difficulty swallowing, so dysphagia, or if they're vomiting. Or if we have them connected to NG suctioning, then oral medications would be contraindicated for that patient. In terms of some key points, when we're administering an oral medication, we want to sit the patient up in an upright seated position, such as a high Fowler's position. We do not want to mix the medications with a large amount of food. So we can crush certain medications with a small amount of food, like a small amount of applesauce or pudding. You don't want to mix it with a lot of food because if the patient decides they don't want any more pudding and don't want any more applesauce, then they're not going to get all of their medication.

Also, it's important to note that you do not crush enteric-coated or extended-release medications. These may not be crushed. You can only crush regular tablets. For liquid medications, when you are measuring those out, when you're holding up the little cup, you want to make sure that the lowest point of the liquid, which is the meniscus, is at the ordered dose level. If we need to administer medications through the NG tube or G tube, we need to first confirm placement of the tube. So if you've just put in an NG tube for a patient, you need to have the location of that NG tube confirmed via x-ray first, before you administer any medications. Once we have that confirmed, then from there on out, you can confirm placement of that NG tube using gastric pH testing. This is where you would aspirate some gastric fluid, check the pH. Gastric pH should be under 5.5. So whenever possible, when you're giving medications via the NG tube route or G tube route, you want to use liquid forms of medications whenever you can. If that's not possible, you can crush tablets in 15 to 30 milliliters of sterile water, and that is not normal saline. You want to use sterile water.

However, just like I mentioned before, we never want to crush enteric-coated or extended-release capsules. You want to flush with 30 milliliters of sterile water before and after medication administration. And if you're administering more than one medication, you want to administer each medication separately and flush with sterile water before and after each medication. Next, we have sublingual or buccal medications. So you always want to administer these types of medications after you provide the patient with their oral medications. As far as placement, you're going to put sublingual medications under the tongue, so sub means under, and lingual means tongue. And you would place buccal medications between the gum and cheek. And it's important to teach your patient not to eat or drink anything until those medications have been completely dissolved. All right. Next, we have transdermal medications. You always want to wear gloves when you're applying transdermal medications. And you never want to cut those transdermal patches. You want to remove the prior dose. So you want to take the prior patch off, fold it in half, and dispose of it properly. And then you want to rotate sites for the patches and apply the patch in a clean, hairless, dry area of the body and label that patch with the date, time, and initials.

Next, let's talk about inhalation therapy, which includes a metered-dose inhaler as well as a dry powder inhaler. So if your patient has to use a metered-dose inhaler, you want to provide teaching for how to do this effectively. So first of all, they should shake their inhaler and attach a spacer, if applicable. They should take a deep breath and exhale. Then they can place the inhaler between their lips and press the inhaler as they take a slow deep breath over 3 to 5 seconds. Then they should hold their breath for 10 seconds, take the inhaler out of their mouth and slowly exhale. Now, if they are using a glucocorticoid inhaler, it's going to be important that the patient rinse their mouth after administration to prevent a fungal infection in the mouth. Now, in terms of a dry powder inhaler, there's a few key differences between this and an MDI. So with a dry powder inhaler, you do not shake the device. You do not attach a spacer. And instead of inhaling slowly and deeply over 3 to 5 seconds, you should advise the patient to breathe in rapidly and deeply over 1 to 2 seconds.

All right. Next, we have optic medication. So these are medications for the eye. With the non-dominant hand, you want to gently lower the patient's lid to expose the conjunctival sac. And you want to drop the medication into that conjunctival sac without touching the tip of the applicator to the eye. Then, after you put the drop in, you want to apply gentle pressure to the nasolacrimal duct here for about a minute. And that will help to prevent systemic absorption. If the patient has multiple eye drops that are ordered, you want to wait about five minutes between the application of those eye drops. All right. Lastly, we're going to talk about otic, or ear medication administration. So you always want to ensure ear drops are at room temperature before administration. You want to lay your patient on their unaffected side so that the affected side is up. You want to pull the pinna up and back for adults, and down and back for children under three years of age. The way I remember this is adults will be taller, so they're up higher, so up and back. And children are shorter, so they'll be down lower. So we want to pull down and back for children. You want to hold the dropper about one centimeter above the ear canal. After you instill the drops, you want to apply gentle pressure to the tragus. And then the patient should remain on their side for about one to two minutes.

Okay, quiz time. I have three questions for you. First question. Why do we apply pressure to the nasolacrimal duct after administration of eye drops? The answer is, to prevent systemic absorption of the medication. Question number two. You should provide sublingual medications before a patient's oral medications. True or false? The answer is false. We want to provide those sublingual tablets after oral medications because they need time to dissolve. And we don't want the patient to swallow them if we were to give them first, and then give them their oral medications that they swallow. Third question. Prior to administration, you need to shake a dry powder inhaler. True or false? The answer is false. So we would shake our metered-dose inhaler, our MDI, but we do not shake our dry powder inhaler. All right. I hope that was helpful. And I want to wish you good luck with studying. Thank you so much for listening.


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