If you search “Which Loxonin S should I buy in Japan?”, the safest answer is:
Do not choose only by the box name. Check the ingredients, warnings, age limit, and pharmacist advice.
This article focuses on the oral Loxonin S tablet series sold as OTC medicine in Japan. It does not cover Loxonin patches, gels, tapes, or other external products.
Loxonin S oral products are common Japanese OTC pain and fever medicines, but the boxes are not all the same. Some are simple oral loxoprofen tablets. Some add stomach-protecting ingredients. Some add other pain-support ingredients or use a different tablet design concept.
This article is a label-reading guide for travelers. It is not a product recommendation or personal medical advice.
Quick Answer: Which Oral Loxonin S Box Are You Looking At?
| Oral box name | Basic meaning | Main point to check |
| Loxonin S | Basic oral loxoprofen pain/fever medicine | Class 1 OTC; pharmacist involvement; age 15+ |
| Loxonin S Plus | Loxoprofen plus magnesium oxide | Adds a stomach-protecting ingredient, but it is still an NSAID and still needs safety checks |
| Loxonin S Quick | Loxoprofen plus a stomach-protecting ingredient, with a quick-disintegrating tablet design | Designed around faster tablet disintegration and a “works quickly” concept; not automatically the best choice for everyone |
| Loxonin S Premium | Loxoprofen plus additional pain-support ingredients | Has extra warnings, including drowsiness/driving-related caution |
| Loxonin S Premium Fine | Menstrual pain-focused oral formula | Still Class 1 OTC and age 15+; check all ingredients and warnings |
For most travelers, the practical question is not “Which is the strongest?” It is:
Which oral product matches my symptom and my safety situation?
The Most Important Things First
Before using an oral Loxonin S product, check these points:
- Oral Loxonin S series products are Class 1 OTC medicines in Japan.
- A pharmacist must be involved in the sale.
- They are generally for people aged 15 and older.
- They contain loxoprofen sodium hydrate, an NSAID-type pain and fever medicine.
- Do not combine them with other pain relievers, fever medicines, cold medicines, or sedatives unless pharmacy staff confirms it is safe.
- Premium has an additional warning about motion sickness medicine and driving or operating machinery.
- Do not drink alcohol around use.
- Ask first if you have asthma triggered by pain relievers, stomach or duodenal ulcer, liver disease, kidney disease, heart disease, blood disease, pregnancy, breastfeeding, older age, dehydration, heat illness risk, or regular medicines.
If the pharmacist counter is closed, you may not be able to buy oral Loxonin S even if the drugstore itself is open.
Why There Are Different Oral Loxonin S Boxes
The shared pain/fever ingredient in the main oral Loxonin S series is loxoprofen sodium hydrate.
The difference is what else the product is designed to do.
Loxonin S
This is the basic oral Loxonin S tablet. It contains loxoprofen sodium hydrate as the active pain/fever ingredient and does not contain a sedative-hypnotic ingredient.
This may be the simpler option to ask about if you do not need added stomach-protecting or pain-support ingredients and only want the basic oral loxoprofen effect, as long as the pharmacist confirms it is suitable for you.
Loxonin S Plus
Loxonin S Plus contains loxoprofen sodium hydrate plus magnesium oxide, described as a stomach-protecting ingredient.
This may be worth asking about if you are worried about stomach irritation from pain medicine. However, the added stomach-protecting ingredient does not remove the usual NSAID cautions.
This does not mean it is safe for anyone with stomach problems. If you have stomach ulcer history, stomach pain, black stool, vomiting blood, kidney disease, or regular medicines, ask before use.
Loxonin S Quick
Loxonin S Quick contains loxoprofen sodium hydrate plus magnesium aluminometasilicate, a stomach-protecting ingredient.
It is designed around a quick-disintegrating tablet concept. The official product positioning emphasizes faster tablet disintegration and quick action for pain such as headache or menstrual pain.
This may be worth asking about if you are worried about stomach irritation and also want a product designed around quicker action. It is still not automatically the best choice for everyone.
Loxonin S Premium
Loxonin S Premium contains loxoprofen sodium hydrate plus additional ingredients, including allylisopropylacetylurea and anhydrous caffeine.
This may be worth asking about for headache when the pharmacist agrees that the added ingredients match your situation. Because it includes a sedative-related ingredient, drowsiness and driving cautions matter more.
The official product information warns not to drive or operate machinery after taking it because drowsiness may occur. This is especially important for travelers who plan to drive, cycle, ski, work, drink alcohol, or take motion sickness medicine.
Loxonin S Premium Fine
Loxonin S Premium Fine is positioned for menstrual pain. It contains loxoprofen sodium hydrate plus additional ingredients such as shakuyaku dry extract, hesperidin, and a stomach-protecting ingredient.
This may be worth asking about when menstrual pain is the main symptom, especially if lower-abdominal cramping is part of the problem. It is not a general “stronger Loxonin” for every kind of pain.
It still requires pharmacist involvement and is not for people under 15. If pain is unusually severe, new, one-sided, accompanied by fever, heavy bleeding, faintness, pregnancy possibility, or worsening symptoms, consider medical care instead.
What to Ask at a Japanese Pharmacy
You can show these phrases:
| English meaning | Japanese to show |
| Which oral Loxonin S product is this? | これは飲み薬のロキソニンSシリーズのどれですか？ |
| Does this contain loxoprofen? | これはロキソプロフェンを含んでいますか？ |
| What ingredients are added besides loxoprofen? | ロキソプロフェン以外に、どんな成分が入っていますか？ |
| Does this have ingredients that may cause drowsiness? | 眠気が出る可能性のある成分は入っていますか？ |
| Can I drive after taking this? | これを飲んだ後に運転してもよいですか？ |
| I already took cold medicine. | すでに風邪薬を飲みました。 |
| I have asthma / stomach ulcer / kidney disease / liver disease / heart disease. | 喘息／胃潰瘍／腎臓病／肝臓病／心臓病があります。 |
| I am pregnant / breastfeeding. | 妊娠中です／授乳中です。 |
| Should I see a doctor instead? | 市販薬ではなく、受診した方がよいですか？ |
For broader pharmacy phrases, see: Show This at a Japanese Pharmacy: OTC Medicine Questions in English and Japanese.
When Not to Self-Treat
Do not rely only on Loxonin S or another OTC pain medicine if symptoms are severe, unusual, worsening, or not improving.
Seek medical care promptly for:
- severe or sudden pain
- chest pain, trouble breathing, weakness, numbness, confusion, or pain spreading to the arm, shoulder, jaw, back, or neck
- severe headache with stiff neck, rash, repeated vomiting, confusion, or neurological symptoms
- high or persistent fever
- severe abdominal pain
- black stool, bloody stool, vomiting blood, or vomit that looks like coffee grounds
- pain after a major injury
- possible heat illness, dehydration, repeated vomiting, or inability to drink fluids
- symptoms in a child under 15, pregnant person, elderly person, or medically fragile person
If symptoms feel severe or urgent in Japan, call 119.
If you are not sure how to find care, see: How to See a Doctor in Japan as a Traveler.
Bottom Line
Oral Loxonin S is not just one box. In Japan, travelers may see Loxonin S, Plus, Quick, Premium, and Premium Fine.
The safest way to choose is:
- Check that it is an oral product.
- Check that it contains loxoprofen.
- Check added ingredients and drowsiness/driving warnings.
- Check age, other medicines, alcohol, pregnancy, and medical conditions.
- Ask the pharmacist before buying or using it.
For a broader ingredient comparison, see: Loxoprofen vs Acetaminophen in Japan: Pain, Fever, Inflammation, and Age Checks.
Related Guides
- Loxoprofen vs Acetaminophen in Japan: Pain, Fever, Inflammation, and Age Checks
- Fever in Japan: How to Choose OTC Medicine Safely as a Traveler or Resident
- Headache Medicine in Japan: OTC Pain Relievers and Safety Checks
- Heat Illness in Japan: What Travelers Should Check Before Taking Fever Medicine
- Drugstore Basics in Japan: How to Buy OTC Medicine Safely
- How to See a Doctor in Japan as a Traveler
References
- Daiichi Sankyo Healthcare. Official Loxonin S product information. https://www.daiichisankyo-hc.co.jp/products/details/loxonin-s/
- Daiichi Sankyo Healthcare. Official Loxonin S Plus product information. https://www.daiichisankyo-hc.co.jp/products/details/loxonin-s_plus/
- Daiichi Sankyo Healthcare. Official Loxonin S Quick product information. https://www.daiichisankyo-hc.co.jp/products/details/loxonin-s_quick/
- Daiichi Sankyo Healthcare. Official Loxonin S Premium product information. https://www.daiichisankyo-hc.co.jp/products/details/loxonin-s_premium/
- Daiichi Sankyo Healthcare. Official Loxonin S Premium Fine product information. https://www.daiichisankyo-hc.co.jp/products/details/loxonin-s_premium_fine/
- Pharmaceuticals and Medical Devices Agency (PMDA). OTC medicine package insert search. https://www.pmda.go.jp/PmdaSearch/otcSearch/
- Ministry of Health, Labour and Welfare. Information on Japan’s OTC medicine sales system. https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000082514.html
