What Is Loxonin? Loxoprofen, Explained in English

Loxonin (ロキソニン, rokisonin) is a brand of painkiller in Japan. Its active ingredient is loxoprofen sodium (ロキソプロフェンナトリウム), a pain and fever reliever in the NSAID group, the same group as ibuprofen.

Depending on where you're from, you may not know it. Loxoprofen isn't listed in the US (DailyMed) or UK (emc) medicine databases. In Japan, you'll see it on the box as ロキソニン or ロキソプロフェン.

Loxonin S vs S Premium vs S Premium Fine

Each dose has the same amount of loxoprofen. Here's what each box adds:

Loxonin SロキソニンS

Just loxoprofen

1 tablet a dose · Class 1 · 15+

Loxoprofen 60 mg per dose, and nothing else active.

Loxonin S PremiumロキソニンSプレミアム

Loxoprofen plus three extras

2 tablets a dose · Class 1 · 15+

Adds allylisopropylacetylurea, caffeine, and a stomach-protecting ingredient (magnesium aluminometasilicate). The insert says not to drive after taking it, because it can make you drowsy.

Loxonin S Premium FineロキソニンSプレミアムファイン

Loxoprofen plus a herbal extract and more

2 tablets a dose · Class 1 · 15+

Adds peony (shakuyaku) extract, hesperidin, and the same stomach-protecting ingredient. The insert says it has no ingredient that makes you drowsy.

Loxoprofen Tablets Kunihiroロキソプロフェン錠「クニヒロ」

Same loxoprofen as Loxonin S

1 tablet a dose · Class 1 · 15+

A different maker, with the same 60 mg of loxoprofen per tablet.

From each package insert. Every ingredient is listed on each product page.

Loxoprofen in a Patch and in Cold Medicine

Loxoprofen also comes in a patch, and in three cold medicines sold by a pharmacist. The cold medicines differ in what they add to it:

Loxonin S TapeロキソニンSテープ

A loxoprofen patch

Once a day · Class 2 · 15+

For back, shoulder, joint, and muscle pain. Up to 4 patches a day, and not for more than 2 weeks in a row.

Loxonin Cold Medicineロキソニン総合かぜ薬

Cold medicine with loxoprofen

Pharmacist-Guidance Drug · 15+

Adds dihydrocodeine, dl-methylephedrine, bromhexine, and clemastine. Abuse-prevention designated.

Colgen Kowa LX TabletsコルゲンコーワLX錠

Cold medicine with loxoprofen

Pharmacist-Guidance Drug · 15+

Adds dihydrocodeine, dl-methylephedrine, guaifenesin, d-chlorpheniramine, and caffeine. Abuse-prevention designated.

Pabron LX TabletsパブロンLX錠

Cold medicine with loxoprofen

Pharmacist-Guidance Drug · 15+

Adds L-carbocisteine, tipepidine, and mequitazine. No dihydrocodeine or dl-methylephedrine, so it isn't abuse-prevention designated.

Don't take a loxoprofen cold medicine together with Loxonin tablets. Each insert says not to combine it with other pain relievers or cold medicines.

How to Take Loxonin S

• Dose: 1 tablet for Loxonin S. 2 tablets for S Premium and S Premium Fine.
• How often: up to 2 times a day. If the symptoms come back, you can take a 3rd dose.
• Gap: at least 4 hours between doses.
• Food: try to avoid taking it on an empty stomach. Take it with water or lukewarm water.
• Age: 15 and up only.

Who Shouldn't Take Loxonin

The package inserts for the Loxonin tablets say not to take them if you:

• Have had an allergic reaction to the product, or asthma after taking it, another pain reliever, or a cold medicine.
• Are under 15.
• Are being treated at a medical institution for a stomach or duodenal ulcer, liver disease, kidney disease, or heart disease.
• Have been told by a doctor that you have a blood disorder (such as anemia, a low platelet count, or a low white blood cell count).
• Are pregnant and within 12 weeks of your due date.

Also from the inserts:

• Don't take other pain relievers, cold medicines, or sedatives at the same time. For S Premium, also no motion sickness medicines.
• Don't drink alcohol before or after taking it.
• Don't take it for a long time. If pain keeps coming back after 3 to 5 days, stop and see a doctor.

Tap a product name above for its full warnings in English, including side effects and the rare serious symptoms to watch for.

Buying Loxonin in Japan

The Loxonin tablets are Class 1 medicines (第1類医薬品, dai-ichi-rui iyakuhin). A pharmacist has to be on duty to sell them, and will explain the medicine before you buy. Loxonin S Tape is Class 2, and the three loxoprofen cold medicines are Pharmacist-Guidance Drugs. Our guide to Japan's medicine classes explains the difference.