How Sublingual Administration Works
Sublingual, from the Latin for "under the tongue," describes a pharmacological route of administration where substances are absorbed directly into the bloodstream through the tissues beneath the tongue. This process is highly effective due to the rich network of tiny blood vessels, or capillaries, that lie just under the surface of the oral mucosa. When a medication is placed in this area, it dissolves quickly, and the active ingredients diffuse into these capillaries. From there, the drug enters the systemic circulation directly, without first passing through the gastrointestinal (GI) tract and the liver.
This method of delivery offers several key advantages over traditional oral pills, which must be swallowed, digested, and then filtered by the liver. The sublingual route avoids the first-pass metabolism, a process where the liver breaks down a portion of the drug before it can reach its target. By bypassing this metabolic process, a higher concentration of the drug can enter the bloodstream, resulting in a more predictable and potent effect at a potentially lower dose. Sublingual medications come in various forms, including fast-dissolving tablets, films, sprays, and lozenges.
What Drug Is Put Under the Tongue? Common Examples
Many different medications utilize sublingual delivery for specific therapeutic reasons. Here are some of the most common examples:
- Nitroglycerin (Nitrostat): One of the most classic and well-known sublingual medications, nitroglycerin is used to treat episodes of angina (chest pain) in individuals with coronary artery disease. The sublingual tablet dissolves quickly, allowing the medication to relax and widen blood vessels, which rapidly relieves chest pain during an attack.
- Buprenorphine/Naloxone (Suboxone): This combination medication is prescribed to treat opioid use disorder. The sublingual film or tablet contains buprenorphine to prevent withdrawal symptoms and reduce cravings, while naloxone is included to prevent misuse by injection.
- Zolpidem (Edluar): A sublingual tablet of this medication is used for the treatment of insomnia, providing a rapid onset of action to help with sleep.
- Asenapine (Saphris): A sublingual tablet used for the treatment of schizophrenia and bipolar disorder. Rapid absorption is beneficial for managing acute symptoms.
- Ergotamine (Ergomar): This medication is used for the acute treatment of migraine headaches. The sublingual route can provide quicker relief than swallowed tablets.
- Vitamins and Supplements: Certain supplements, like vitamin B12 and vitamin D, are available in sublingual formulations. This can be beneficial for individuals with absorption issues in the GI tract.
Advantages of Sublingual Administration
Sublingual administration offers several significant benefits that make it the preferred route for certain medications:
- Faster Onset of Action: For conditions requiring immediate relief, such as angina, the rapid absorption via the sublingual route is a critical advantage.
- Higher Bioavailability: By bypassing the liver's first-pass metabolism, a higher percentage of the drug reaches the systemic circulation, meaning a more predictable and often lower dose can be used.
- Alternative for Swallowing Difficulties: Patients who struggle to swallow pills, such as children or elderly individuals, can benefit from sublingual formulations.
- Avoids GI Tract Breakdown: Drugs that would be destroyed by stomach acid or digestive enzymes are protected by the sublingual route.
- Reduced Food/Drug Interactions: Because the medication bypasses the stomach and its contents, the risk of interactions with food or other medications in the GI tract is minimized.
Disadvantages and Proper Sublingual Technique
While highly effective, sublingual administration is not suitable for every medication or patient. Disadvantages include the risk of irritation to the oral mucosa and the limitation that only small doses can be absorbed efficiently this way. The taste of some medications can also be unpleasant. To ensure proper administration, follow these steps:
- Preparation: Sit upright and ensure your mouth is moist. Drinking water 10-15 minutes beforehand can help.
- Placement: Place the tablet or film directly under your tongue.
- Dissolution: Allow the medication to dissolve completely without chewing, swallowing, or talking.
- Wait: Avoid eating, drinking, or smoking while the medication is dissolving and for at least 30 minutes afterward to prevent washing the drug away.
Comparison Table: Sublingual vs. Oral Administration
| Feature | Sublingual Administration | Oral (Swallowed) Administration |
|---|---|---|
| Speed of Onset | Rapid (minutes) | Slower (30+ minutes) |
| Bioavailability | High and predictable | Variable, affected by digestion |
| First-Pass Metabolism | Avoided | Extensive for many drugs |
| GI Tract Exposure | Bypassed | Exposed to stomach acid and enzymes |
| Swallowing Issues | Ideal for patients with difficulties | Difficult or impossible for some patients |
| Dose Size | Limited to small amounts | Can accommodate larger doses |
Conclusion
Sublingual administration is a powerful and valuable drug delivery method used for specific medications where speed and efficacy are paramount. By leveraging the highly vascularized area under the tongue, drugs can bypass the digestive system and liver, leading to a faster onset of action and higher, more predictable bioavailability. This route is not a universal solution, as some medications are unsuitable due to taste, irritation, or dose size. However, for critical medications like nitroglycerin for chest pain and buprenorphine for opioid use disorder, knowing what drug is put under the tongue and how to administer it properly is essential for achieving optimal therapeutic outcomes.
This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting or changing any medication regimen. For more detailed information on specific medications, visit the FDA's drug database.
