Oral Dosage Forms 101
Full update September 2017
There’s a wide variety of oral dosage forms available. Capsules, tablets, and liquids are likely to come to mind immediately. However, these categories can be broken down further. There are different kinds of tablets, such as immediate-release, extended-release (including controlled- and sustained-release), chewable, orally disintegrating, effervescent, buccal, and sublingual. For capsules, there are immediate-release, extended-release, and sprinkle. Oral liquids include solutions, syrups, suspensions, and elixirs. And then there are a number of other oral dosage forms, such as lozenges and troches, powders, sprays, and films (or strips). Adding a possibility for confusion, there are even tablets and capsules that should NOT be taken orally.
Any of the dosage forms mentioned can require special considerations when they’re prescribed and dispensed to patients, or when they’re purchased over-the-counter.
Mr. Morris comes into the pharmacy to drop off a prescription for his 3-year-old daughter, Claire. The prescription is for Singulair 4 mg to be taken by mouth once daily. You confirm the demographic information you have on file for Claire and ask about allergies. You update Claire’s weight in the computer and write it on the prescription hardcopy. As you start to enter the prescription into the computer system, you notice that Singulair is available as a 4 mg chewable tablet and 4 mg oral granules. It isn’t clear from the prescription which product the prescriber intended to order, and this is the first time Claire is getting this medication filled at your pharmacy. You ask the pharmacist for help.
How do oral dosage forms work?
Most oral dosage forms are meant for absorption into the bloodstream. Once in the bloodstream, they are transported throughout the body to have their effect. Examples of this would be most oral tablets, capsules, and liquids. The drug is swallowed, travels down through the gastrointestinal (GI) tract, and is absorbed into the blood through the lining of the stomach or small intestine. The drug can then act on receptors in different parts of the body to have its specific effect.
It’s important to understand the difference between immediate-release tablets and capsules and extended-release tablets and capsules. Extended-release formulations have a special coating or other mechanism to help release the drug more slowly. Often, this can reduce the number of times a day that a patient needs to take a drug. For example, immediate-release diltiazem (Cardizem) is given three or four times a day. However, extended-release formulations of diltiazem, like Cardizem CD, can be given just once a day. (However, you can’t depend on suffixes to have uniform meanings. We have more information on drug names with suffixes in our technician tutorial, What Drug Names Really Mean.)
Sprinkle capsules, such as Depakote (divalproex) sprinkle (U.S.) or Topamax (topiramate) sprinkle, can either be swallowed whole or opened, and the contents taken by mouth, usually with some food such as applesauce. But don’t assume all sprinkle capsules can be swallowed whole. For example, AcipHex Sprinkle capsules (rabeprazole [U.S.]) should NOT be swallowed whole; the capsule must be opened and the contents sprinkled on food. Swallowing the capsule whole could cause this drug to not work as well.
Some drugs, such as proton pump inhibitors (e.g., omeprazole, lansoprazole, etc), are formulated to delay the release of the drug. These delayed-release capsules help ensure that the drug is released in a specific part of the GI tract so exposure to acid, which could destroy the drug, is reduced.
Most oral liquids can be thought of as similar to immediate-release tablets or capsules. Liquids can come as suspensions, solutions, syrups, and the less common elixirs.
Chewable tablets are a convenient dosage form for children and adults who have a hard time swallowing pills. These are intended to be chewed first and then swallowed. Examples of chewable tablets include antacids; chewable low-dose aspirin; Fosrenol (lanthanum carbonate); Singulair (montelukast) chewable tablets; and children’s versions of Tylenol (acetaminophen), Advil (ibuprofen), Benadryl (diphenhydramine), etc. Chewable tablets are most useful for their ease of administration. Some chewable tablets may get absorbed faster in the stomach because chewing the drug helps start the process of breaking it down for absorption.
In most cases, swallowing tablets meant to be chewed shouldn’t cause any issues. The stomach will just have to do more work to break them up. However, there can be exceptions. For example, Fosrenol MUST be chewed before swallowing because it can cause severe GI problems if swallowed whole (blockage of the intestines, formation of holes in the GI tract, etc). Get the pharmacist involved if a patient asks if they can chew a med not meant to be chewed. In some cases, this can be dangerous, such as with extended-release meds which can release large doses all at once if chewed.
Buccal and sublingual tablets or films are also meant for absorption into the blood. However, the drug is actually absorbed into the blood through the lining of the mouth instead of the lining of the stomach or small intestine. So these don’t need to be swallowed to be absorbed. (If they are swallowed, they may take longer to work and/or be less effective). Buccal tablets such as Fentora, a formulation of fentanyl, are placed between the teeth and the cheek. Sublingual tablets, such as nitroglycerin (Nitrostat), go under the tongue. An advantage to these types of tablets is that they act quickly, since they skip steps such as moving down through the esophagus and into the stomach. So it makes sense that some meds for pain, like fentanyl, and meds for chest pain related to heart issues, like nitroglycerin, are formulated in this way.
Orally disintegrating tablets (e.g., Maxalt-MLT – U.S. and Maxalt RPD – Canada [rizatriptan], Zyprexa Zydis [olanzapine], Zofran ODT [ondansetron], etc), or orally soluble/disintegrating films (e.g., Zuplenz – U.S. and Ondissolve ODF – Canada [ondansetron]) are kind of tricky. As the name implies, these dissolve in the mouth and should be placed on top of the tongue. However, they still need to be swallowed so that the drug can be absorbed through the GI tract. Because of this, they may not be a good choice for patients who can’t swallow, such as those with breathing tubes. The advantage of orally disintegrating tablets and films is that they fall apart in the saliva, and can then be easily swallowed with or without taking a drink of liquid. They’re good because patients can’t hold them in their cheeks, pretend to swallow them, and later spit them out. So it makes sense that some medications for psychiatric conditions, such as olanzapine, are formulated as orally disintegrating tablets. It also makes sense that anti-nausea medications, like ondansetron, and triptans for migraines, like rizatriptan, are formulated in this manner. These oral dosage forms provide an option for patients who are too nauseous to drink liquid or swallow a tablet or capsule.
Effervescent tablets (e.g., Airborne [vitamin supplement], Alka-Seltzer Original – U.S. and Alka-Seltzer Fast Relief – Canada [antacid/aspirin], Binosto – U.S. [alendronate], Effer-K – U.S and K-Lyte – Canada [potassium citrate/potassium bicarbonate], etc) are typically placed in water to dissolve completely, then swallowed. The problem with effervescent tablets is that they can contain a lot of sodium since sodium bicarbonate is the ingredient that typically gives them their “fizz.” (Effervescent potassium supplements have potassium bicarbonate instead of sodium bicarbonate.) Consider that most people should limit their total sodium intake per day to about as much found in one teaspoon of table salt (about 2,300 mg). One Alka-Seltzer Original (or Fast Relief in Canada) tab alone has over 500 mg of sodium and one Airborne effervescent tab has over 200 mg.
Powders are another dosage form that requires swallowing and for the drug to travel to the stomach for absorption. These can be mixed with liquid and swallowed, or placed on the tongue and washed down with a drink of liquid. Some examples of oral powders are Goody’s Powders (U.S. only) and BC Powders (U.S. only), both OTC pain relievers. Oral granules, which are similar to a powder but more grainy, are also an available dosage form for drugs like Singulair and Kalydeco (ivacaftor).
The pharmacist reaches out to the prescriber and confirms that the prescription is for Singulair 4 mg chewable tablets, not the oral granules.
Do ALL oral dosage forms work by getting absorbed into the blood?
No, not all oral dosage forms work by getting absorbed into the blood. There are some medications that are swallowed, but work by having local effects in the GI tract. Examples of this would include bismuth (Pepto-Bismol, etc) and sucralfate (Carafate [U.S.], Sulcrate [Canada]). These drugs are both used to coat the lining of the stomach to protect it from injury from acid. They do not work by being absorbed into the blood.
Most lozenges, sprays, troches, and some liquids act locally in the mouth or throat. Think about Chloraseptic lozenges and spray for numbing a sore throat. Or about nystatin suspension or clotrimazole troche (U.S. only), which treat fungal infections in the mouth and throat. (Some exceptions here include the fentanyl lozenge, Actiq [U.S. only], and nitroglycerin sprays, Nitrolingual, etc, which are absorbed into the blood stream and ARE NOT used for their local effects.)
What are the EXCEPTIONS, such as capsules or tablets, which are not to be placed in the mouth at all?
Watch for capsules whose contents are meant to be inhaled with the use of an inhaler device to act in the lungs, such as Arcapta (indacaterol [U.S.]) or Spiriva (tiotropium) for chronic obstructive pulmonary disease (COPD). And watch for tablets that are meant for vaginal use where they act locally, such as Vagifem (estradiol). These will require special attention to make sure patients understand how to use them. Since these may be referred to as, and look like, oral “capsules” and “tablets,” they can be especially tricky. If patients swallow them, they won’t have the desired effect, which could be dangerous. For example, COPD patients who swallow a capsule meant for inhalation could end up with severe breathing problems requiring medical attention.
How can I help prevent errors with oral dosage forms?
Make sure the directions for use are clear. For example, the directions on a label for nystatin suspension should clearly state to swish in the mouth before swallowing or spitting it out. Otherwise, the drug may not be effective in clearing a yeast infection from the mouth. It’s also important for patients to know if these types of meds should be “swished and spit” or “swished and swallowed.”
Patients should be made aware of the amount of water effervescent tabs should be dissolved in, and that the tabs must be fully dissolved in water prior to taking. Swallowing effervescent tabs whole can lead to choking or irritation of the stomach and esophagus. Check with the pharmacist about how he/she prefers to share this information with patients, if it isn’t clear from the instructions provided by the prescriber. For example, your pharmacy may have auxiliary labels that include instructions for how to take effervescent tabs.
The directions for sublingual tabs (or films, such as Suboxone – U.S. [buprenorphine/naltrexone]) should state to place the dose under the tongue. The directions for buccal tablets (or films, such as Onsolis – U.S. [fentanyl]) should state to place the dose in-between the cheek and molar. Otherwise, the patient might simply swallow them.
The same is true for inhaled capsules and vaginal tablets. These should have explicit directions for use. Don’t assume that the patient knows what to do with different dosage forms. There are endless stories of patients who have used drugs incorrectly because they did not have proper information describing how to take them.
Watch that the product can be taken as directed. For example, if you know that a patient cannot swallow a capsule or tablet, these might be inappropriate dosage forms unless they can be crushed (tablet) or opened (capsule). This is especially true in the hospital setting, where patients are more likely to have medications given through a feeding tube. Use our chart, Meds That Should Not Be Crushed, to find this information.
If a dose is ordered that would necessitate the patient taking a fraction (usually half) of a tablet, it’s important to make sure that dividing the tablet is okay. Often, extended-release tablets should NOT be split. We have a technician tutorial, Which Tablets and Capsules Can Be Crushed, Opened, or Split?, dedicated to this topic, and an algorithm called Tablet Splitting: “To Split or Not to Split.” If you notice that there are problems with the way a tablet or capsule is supposed to be given, alert the pharmacist.
Make sure the patient has a good way to measure the appropriate dose. Dispense a measuring device with oral liquids (i.e., calibrated dosing cup, dropper, spoon, or oral syringe) that don’t already come with one. Using a household teaspoon for measuring oral liquids is a bad idea, because the amount of liquid they hold can vary. Also, make sure that the dosing units on the prescription label match the dosing units on the measuring device to avoid confusion for the patient.
In the hospital setting, you’re likely to be packaging individualized doses of oral liquids for patients. Regardless of your practice setting, NEVER send oral meds in IV syringes. This could lead to administration of the oral med through an IV line, which is a potentially serious error. Always package oral liquids in ORAL syringes that can’t be connected to IV lines, or other packaging that is specific for oral liquids (e.g., amber bottles, etc). Use “For oral use only” auxiliary labels on these syringes as an extra precaution.
Suggesting a pill splitter for patients who require a fraction of a tablet is also a good idea. For patients with poor coordination or eyesight, a special easy-to-use pill splitter might really help. Or the pharmacist might prefer that the tablets be split BEFORE they are dispensed to the patient. In the hospital setting, you will usually dispense tabs that are already split, instead of whole tabs for the nurse to split. Double-check with the pharmacist if you’re not sure what to do. It’s important to help ensure that patients get the most accurate dose possible.
Follow the right technique when handling oral suspensions. Many oral suspensions, such as antibiotic suspensions for pediatrics, need to be reconstituted. When reconstituting suspensions, make sure to tap and invert the bottle a few times first. This will help loosen the powder that may have settled. Then add the quantity of water indicated on the package labeling in two steps. First, add about one-half to two-thirds of the total amount of water for reconstitution. Shake the bottle vigorously to uniformly suspend the powder. Then add the remaining quantity of water, shaking vigorously again to make sure the powder is distributed evenly. Some oral suspensions come pre-made, such as sulfamethoxazole/trimethoprim, nystatin, and Tussionex (hydrocodone/chlorpheniramine – U.S hydrocodone/phenyltoloxamine – Canada). Shake these pre-made suspensions well before pouring to distribute the medication and ensure the patient will get enough drug in each dose.
As you are filling Claire’s prescription for Singulair 4 mg chewable tablets, you see that there is a generic available. You select the generic, montelukast sodium, double checking to make sure you pick the chewable tablets, and not one of the other oral dosage forms also available as a generic. You then proceed to enter instructions that say, “Chew and swallow 1 tablet by mouth once a day.”
Do any of these dosage forms require special labeling?
Use auxiliary labels to indicate if a med should be taken with food or on an empty stomach. The contents of the stomach and changes in acidity caused by meals can cause more or less drug to be absorbed into the blood, depending on the characteristics of the drug. For example, levothyroxine should be given first thing in the morning on an empty stomach, because calcium, fiber, iron, etc, found in food can reduce its absorption. On the other hand, the cholesterol-lowering drug lovastatin should be taken with food, so that it is absorbed to the fullest extent. Other drugs, like amoxicillin/clavulanate (Augmentin [U.S.], Clavulin [Canada]) and ibuprofen, should be given with food, not only because stomach contents can affect absorption, but because having food in the stomach can prevent stomach upset from the drug.
Put on labels that indicate proper storage. Liquids are more likely to require refrigeration than other oral dosage forms. In fact, they will often have a shorter beyond-use date than other oral dosage forms. For example, unreconstituted cephalexin suspension can be stored at room temperature up to the expiration date. However, once reconstituted, the suspension should be refrigerated and given a beyond-use date of 14 days.
It’s uncommon, but refrigeration may be recommended for some capsules or tablets, like some probiotics or ritonavir (Norvir) capsules (U.S.). Refrigeration is recommended for ritonavir caps if they aren’t going to be used within 30 days.
For those meds that should not be taken orally, such as Arcapta and Spiriva capsules and Vagifem tablets, provide information for the patient to keep the med in its original packaging. Placing these in pill organizers can increase the risk that they will be taken orally and swallowed by mistake.
Effervescent tablets must also be kept in their original packaging until they are used. This helps keep them dry. If they are exposed to moisture during storage they might break down or start to dissolve on their own.
Use an auxiliary label to indicate tablets and capsules that should NOT be taken orally. Place an auxiliary label stating that meds such as inhaled capsules and vaginal tablets are not to be taken by mouth. If possible, also include a “for inhalation” or “for vaginal use” auxiliary label on these meds.
Use any other applicable auxiliary labels. Any of the usual auxiliary labels should be used for oral dosage forms (e.g., “do not split, chew, or crush,” “may cause drowsiness,” “avoid exposure to the sun,” etc) as appropriate. And liquid suspensions will require a “shake before using” label.
As you are preparing Claire’s prescription, you make sure to apply an auxiliary label to remind Claire’s parents that the medication should be chewed before swallowing. You also add an auxiliary label to let her parents know that this drug is a generic substitute for Singulair.
Project Leader in preparation of this technician tutorial (330980): Flora Harp, PharmD, Assistant Editor
Cite this document as follows: Technician Tutorial, Oral Dosage Forms 101. Pharmacist’s Letter/Pharmacy Technician’s Letter. September 2017.
“Cheat Sheet” for Handling Oral Dosage Forms
Be familiar with the different oral dosage forms available:
- Extended-release – often dosed once a day; has coating or mechanism to release the drug slowly
- Chewable – chewed first, then swallowed
- Buccal – placed between the teeth and cheek and absorbed through the mouth lining
- Sublingual – placed under the tongue and absorbed through the mouth lining
- Orally disintegrating – dissolved in mouth and swallowed
- Effervescent – dissolved in a specific amount of water, then the patient drinks the solution
- Sprinkle – can be opened and the contents sprinkled on food
- Powders and Granules – can be mixed with food or placed on tongue
- Films or strips – buccal, sublingual, or orally soluble/disintegrating
- Lozenges or troches – dissolves slowly in the mouth (takes longer to dissolve than orally disintegrating tablets); often used for local effects
- Sprays – sprayed in the mouth; often used for local effects
Prevent errors with oral dosage forms:
- Select the right product if there are multiple oral dosage forms available for the same brand or generic med
- Make sure directions for use are clear and specific
- Confirm that the product can be taken as directed
- Watch for patients who have difficulty swallowing
- Watch for prescriptions necessitating the patient take a fraction of a particular dosage form
- Make sure manipulating the dosage form is okay first; check with the pharmacist if unsure
- Ensure the patient has a good way to measure the appropriate dose
- NEVER send oral meds in or with syringes used for injection
- Always provide a calibrated measuring device; do NOT rely on household measuring tools
- Make sure dosing units on prescription match dosing units on measuring device
- Follow the right technique when handling oral suspensions
- When reconstituting, ensure powder is uniformly distributed
- Shake pre-made suspensions very well before pouring
- Apply special labeling as needed
- Take with food or take on an empty stomach
- Proper storage
- “Do not take orally,” for inhaled capsules and vaginal tablets
- “Do not split, chew, or crush,” for extended-release tablets and capsules
- “Shake well,” for suspensions
[September 2017; 330980]
- Get the Answers to Common Questions About Chewable Tabs
- Read Each New Order Twice to Ensure You Dispense the Right Dosage Form
- Draw Up Doses of Oral Liquids in Oral Syringes NOT IV Syringes
- Many patients don't realize how much sodium is in some effervescent tablets...<em>Airborne</em>, <em>Alka-Seltzer</em>, <em>Binosto</em>, etc
- avoiding mishaps with tablets and capsules that should NOT be swallowed