A white, round pill marked K18 can match 2 prescription medicines in the United States. The placement of the imprint and the score line separate them, so both sides of the tablet must be checked before identification.
- K and 18 on the same face, separated by a score line, with a blank back: oxycodone hydrochloride 5 mg.
- K on one face and 18 on the other, with no score line: olmesartan medoxomil 20 mg.
Do not take a loose pill until a pharmacist confirms it.
K18 pill identification: 2 possible matches
| Feature | Oxycodone hydrochloride | Olmesartan medoxomil |
| Strength | 5 mg | 20 mg |
| Color and shape | White and round | White and round |
| Imprint | K and 18 on the same face | K on one face and 18 on the other |
| Score line | Between K and 18 | No score line |
| Back | Blank | Marked 18 |
| Size | About 6 mm | About 8 mm |
| Main use | Severe pain | High blood pressure |
| Controlled status | Schedule II | Not controlled |
The scored oxycodone tablet has K and 18 together on one face. The unscored olmesartan tablet has one part of the imprint on each face.
Color can change slightly in photographs because of lighting, cameras, and screen settings. Check the imprint layout, score, size, shape, both faces, and the original pharmacy label. For comparison, another white 5 mg oxycodone tablet carries the M 05 52 imprint rather than K18.
What should you do with an unknown K18 pill
- Check both faces in good light.
- Look for a score line and note where K and 18 appear.
- Compare the tablet with the description on its pharmacy container.
- Place a loose pill in a closed container away from children and pets.
- Ask a pharmacist to examine it before anyone takes it.
Emergency: Call 911 if someone collapses, has a seizure, has trouble breathing, or cannot be awakened. For an uncertain pill exposure without those emergency signs, call Poison Control at 1-800-222-1222 in the United States.
What is the oxycodone K18 pill
The scored K18 tablet contains oxycodone hydrochloride 5 mg. It is an immediate-release prescription opioid used for pain severe enough to require an opioid when other treatments do not provide enough relief or cannot be used.
Oxycodone changes how the brain and nervous system respond to pain. It can also cause sleepiness and slow breathing. The K18 oxycodone tablet is a Schedule II controlled substance because it has accepted medical uses and a high risk of misuse and dependence.
What is K18 oxycodone used for
A prescriber may use immediate-release oxycodone for severe short-term pain after surgery or injury. It may also be used for some severe ongoing pain when other treatment choices are inadequate.
The reason for treatment, dose, and length of use depend on the patient. Take oxycodone only under the directions written on your prescription label.
What is the olmesartan K18 pill used for
The unscored 8 mm K18 tablet contains olmesartan medoxomil 20 mg. It is a prescription medicine used to lower high blood pressure.
Dizziness is its most common listed side effect in adults. Olmesartan may affect kidney function or raise potassium levels, so some patients need blood tests. Severe, ongoing diarrhea with weight loss needs medical advice.
Contact the prescriber promptly if pregnancy occurs because olmesartan can harm a developing baby. Confirm the pill with a pharmacist and follow the prescription label.
Is K18 oxycodone 5 mg a strong pill
The K18 tablet contains 5 mg of immediate-release oxycodone. It is the lowest tablet strength in this manufacturer’s immediate-release oxycodone range, but it can still cause dangerous breathing problems, overdose, dependence, and addiction.
A dose that is appropriate for one patient may be unsafe for another. Opioid tolerance, age, health conditions, and other medicines can change how strongly oxycodone affects a person.
How should K18 oxycodone be taken
- Follow the dose and timing on the prescription label.
- Use the lowest prescribed dose for the shortest prescribed time.
- Take it with or without food, as directed on the prescription label.
- Do not take an early or extra dose.
- Do not share oxycodone with another person.
- Do not combine it with alcohol.
- Do not drive until you know how the medicine affects you.
The score line does not mean every patient should split the tablet. Divide it only when the prescriber or pharmacist has told you to do so.
How long does the K18 pill last
The exact length of pain relief varies from person to person. K18 oxycodone is an immediate-release tablet, and its prescribing information uses 4-to-6-hour intervals as needed for pain. Follow the schedule on your own prescription. Do not take an early or extra dose because the pain returns.
Oxycodone can remain in the body after pain relief fades. Sleepiness and breathing effects may continue, especially after a higher dose or when it is combined with another medicine that slows the nervous system.
Is K18 the same as Percocet or OxyContin
| Medicine | Ingredients | Release type | Key detail |
| K18 | Oxycodone only | Immediate-release | Contains no acetaminophen |
| Percocet | Oxycodone and acetaminophen | Immediate-release | Acetaminophen affects its safety limits |
| OxyContin | Oxycodone only | Extended-release | Used on a fixed schedule for severe persistent pain |
These products contain oxycodone, but they are not interchangeable. Each has separate dosing instructions and risks. A white oxycodone-acetaminophen tablet marked 512 contains 5 mg of oxycodone plus 325 mg of acetaminophen, while K18 oxycodone contains oxycodone alone.
K18 oxycodone side effects
Common side effects
- Nausea
- Constipation
- Vomiting
- Headache
- Itching
- Trouble sleeping
- Dizziness
- Weakness
- Sleepiness
Other possible side effects include dry mouth, sweating, stomach pain, or a rash. Contact the prescriber if a side effect is severe, continues, or interferes with normal activities.
Serious side effects
Get urgent medical help for any of these symptoms:
- Slow, shallow, difficult, or stopped breathing
- Extreme sleepiness or difficulty waking
- Fainting or severe dizziness
- Swelling of the face, lips, tongue, or throat
- A seizure
- Severe confusion or unusual agitation
Oxycodone overdose signs
- Slow, irregular, or stopped breathing
- Very small pupils
- Blue, gray, or pale lips and skin
- A limp body
- Choking, snoring, or gurgling sounds
- Loss of consciousness or inability to wake
What to do if an opioid overdose is suspected
- Call 911 immediately.
- Give naloxone if it is available. Follow the product directions and give another dose when directed if the person does not respond.
- Start rescue breathing or CPR if you are trained and the person is not breathing.
- Place the person on their side if they are breathing but unconscious.
- Stay with the person until emergency workers arrive.
Naloxone can temporarily reverse an opioid overdose, but its effects may wear off before oxycodone leaves the body. Emergency care is still needed after naloxone is given.
Ask a pharmacist or prescriber whether you should keep naloxone at home, especially if you take other medicines that cause drowsiness or if someone in your household could accidentally reach the oxycodone.
K18 oxycodone drug interactions
Tell the prescriber and pharmacist about every prescription medicine, over-the-counter product, vitamin, and supplement you use. Several combinations can cause severe sleepiness, slowed breathing, coma, or death.
- Alcohol
- Benzodiazepines such as alprazolam, diazepam, or lorazepam
- Sleep medicines and other medicines that make you sleepy
- Muscle relaxants
- Gabapentin or pregabalin
- Other opioid medicines
- Some antidepressants, migraine medicines, and other drugs that affect serotonin
- Monoamine oxidase inhibitors (MAOIs) taken now or within the past 14 days
- Some antibiotics, antifungal medicines, seizure medicines, and HIV medicines that change oxycodone levels
A pharmacist can check the exact products and doses. Do not start, stop, or change another medicine without medical advice when you are taking oxycodone.
Counterfeit K18 pills and fentanyl risk
A tablet obtained outside a licensed pharmacy may be counterfeit even when its color, shape, and imprint look correct. Counterfeit opioid pills may contain illegally made fentanyl, another drug, too much medicine, or no oxycodone. Counterfeit M30 pills are another example of tablets that may closely copy prescription oxycodone.
Visual inspection cannot prove what a loose tablet contains. Use only medicine prescribed to you and dispensed in a labeled container by a licensed pharmacy.
Can K18 oxycodone cause dependence or addiction
Oxycodone can cause physical dependence and addiction, including when it is taken as prescribed. These terms describe different problems:
- Tolerance means the same dose may have less effect over time.
- Physical dependence means withdrawal symptoms can occur when the medicine is reduced or stopped.
- Addiction involves continued use despite harm, loss of control, or strong urges to use the drug.
Tell the prescriber if you take more than directed, run out early, feel unable to control your use, or use oxycodone for reasons other than pain relief. Treatment is available.
Oxycodone withdrawal
Stopping oxycodone suddenly after regular use can cause withdrawal. Symptoms may include restlessness, sweating, runny nose, watery eyes, muscle aches, trouble sleeping, nausea, vomiting, stomach cramps, or diarrhea.
A prescriber can reduce the dose gradually when treatment ends. Seek medical advice before stopping regular oxycodone use.
Pregnancy and breastfeeding
Extended oxycodone use during pregnancy can cause withdrawal in a newborn. Tell the prescriber if you are pregnant, planning pregnancy, or become pregnant during treatment.
Oxycodone passes into breast milk. A breastfed infant exposed to oxycodone should be watched for unusual sleepiness, poor feeding, limpness, or breathing problems. Get immediate medical help if these signs appear.
Olmesartan can harm a developing baby. A patient who becomes pregnant while taking the olmesartan K18 tablet should contact the prescriber promptly.
Health conditions that require medical advice
Make sure the prescriber knows if you have any of these conditions before taking oxycodone:
- An allergy to oxycodone
- Asthma, sleep apnea, chronic lung disease, or another breathing problem
- A head injury, seizure disorder, or increased pressure in the brain
- A known or suspected bowel blockage
- Low blood pressure
- Liver or kidney disease
- Problems with the gallbladder, pancreas, thyroid, or adrenal glands
- A personal or family history of substance use problems
Older adults and people who are weak or underweight may be more sensitive to breathing problems and sleepiness. Their treatment may need closer monitoring.
Storage and disposal
Store K18 tablets at room temperature in a closed container away from moisture and light. Keep oxycodone locked away from children, visitors, and pets because one accidental dose can be fatal.
Use a medicine take-back location or mail-back program for unwanted oxycodone when one is available. If a take-back option is not readily available, FDA includes medicines containing oxycodone on its flush list. Follow the current FDA disposal directions or ask a pharmacist.
Final thoughts
Check the score line, both faces, and the pharmacy label before taking a K18 pill. If any detail does not match, set the pill aside and ask a pharmacist to identify it.
References
1. DailyMed. Oxycodone Hydrochloride Tablets USP
2. DailyMed. Olmesartan Medoxomil Tablets USP
3. Drugs.com. K 18 Pill Images
6. FDA. Disposal of Unused Medicines
7. FDA. Flush List for Certain Medicines
8. Poison Control. What Is Naloxone
Medical disclaimer: This article is for general education and pill-identification awareness. It does not replace diagnosis, treatment, or advice from a doctor, pharmacist, or Poison Control. Do not take an unknown tablet based only on an online description or image.