Losec
Losec 20 mg reduces stomach acid and is used by adults for short-term relief of heartburn and acid reflux.
Form
enterotabletti
Strength
20 mg
Active Ingredient
Omeprazole magnesium
Manufacturer
Bayer Oy
How to Use
Dosage
One 20 mg tablet.
Method
Take one tablet whole with at least half a glass of water, preferably in the morning. You can take it with or without food. Do not chew or crush the tablet.
Important
The maximum daily dose is one 20 mg tablet. Do not use for more than 14 days without talking to a doctor.
Possible Side Effects
COMMON
- •Headache.
- •Stomach or gut problems like constipation, diarrhea, stomach pain, and gas.
- •Feeling sick (nausea) or throwing up (vomiting).
- •Small growths in the stomach (benign polyps).
RARE
- •Swelling in the feet and ankles.
- •Trouble sleeping (insomnia).
- •Dizziness, tingling feeling, or feeling sleepy.
- •Feeling of spinning (vertigo).
- •Changes in blood tests that show how your liver is working.
- •Skin rash, itchy skin, or hives.
- •General feeling of being unwell and lack of energy.
- •Changes in blood tests like fewer white blood cells or platelets, which can cause weakness, bruising, or make you prone to infections.
- •Severe allergic reactions, including swelling of lips, tongue, throat, fever, or wheezing.
- •Low sodium in the blood, which can cause weakness, vomiting, and cramps.
- •Feeling agitated, confused, or depressed.
- •Changes in taste.
- •Vision problems, such as blurred vision.
- •Sudden wheezing or shortness of breath.
- •Dry mouth.
- •Sore mouth.
- •Oral thrush (a fungal infection in the mouth that can also affect the gut).
- •Microscopic colitis (inflammation of the large intestine).
- •Liver problems, including jaundice (yellow skin), dark urine, and tiredness.
- •Hair loss.
- •Rash caused by sunlight.
- •Joint pain or muscle pain.
- •Severe kidney problems.
- •Increased sweating.
- •Changes in blood, like a severe lack of white blood cells (agranulocytosis).
- •Aggression.
- •Seeing, feeling, or hearing things that are not there (hallucinations).
- •Severe liver problems that can lead to liver failure or brain inflammation.
- •Sudden severe skin rash with blistering or peeling skin, possibly with high fever and joint pain (e.g., Stevens-Johnson syndrome).
- •Muscle weakness.
- •Enlarged breasts in men.
- •Low magnesium in the blood, which can also cause low calcium or potassium in the blood.
- •Rash, possibly with joint pain.
Important Warnings
- Do not use if you are allergic to omeprazole or similar medicines (proton pump inhibitors).
- Do not use if you are taking nelfinavir (an HIV medicine).
- Do not use for more than 14 days without talking to a doctor.
- Talk to a doctor if your symptoms do not get better or get worse during treatment.
- Tell your doctor right away if you get a rash, especially in areas exposed to sunlight, as treatment may need to be stopped.
Show 5 more warnings
- Omeprazole can cause kidney inflammation. Contact your doctor if you have less urine, blood in urine, fever, rash, or joint stiffness.
- Contact a doctor immediately if you lose a lot of weight for no reason, have trouble swallowing, get stomach pain or indigestion, vomit food or blood, have black or bloody stools, get severe or constant diarrhea, have a history of stomach ulcers or stomach surgery, have been treated for stomach problems or heartburn for more than 4 weeks, have jaundice or severe liver disease, are over 55 and have new or changed symptoms.
- Do not use omeprazole as a preventive medicine.
- This medicine is only for adults aged 18 years or older.
- Tell your doctor or pharmacist about all other medicines you are taking, as Losec can affect them and vice versa. This includes blood thinners (e.g., clopidogrel, warfarin), antifungals (e.g., ketoconazole), digoxin, diazepam, phenytoin, rifampicin, atazanavir, tacrolimus, methotrexate, St. John's Wort, cilostazol, saquinavir.
Use in Elderly Patients
Category A
Suitable for older adults. For short-term use only. Consider the numerous potential interactions, especially with clopidogrel and (es)citalopram. Avoid long-term use. Long-term use carries an increased risk of adverse effects. Risk of hypomagnesemia in prolonged use. (updated 10.11.2025)