Omeprazole

What it is

Omeprazole is a proton pump inhibitor: it shuts down the enzyme that pumps acid into the stomach, so far less acid is produced across the day. Lower acid lets heartburn settle and gives an irritated stomach lining or an ulcer a chance to heal. It is sold without prescription for reflux and heartburn, and is also used as part of ulcer treatment.

Used for

• Heartburn
• Ulcer

What to know while taking it

It acts on acid pumps as they switch on, so it is taken before breakfast rather than with food. Because it removes the acid step that absorption depends on, long use can pull down vitamin B12, magnesium, iron and calcium, which is why those markers and ferritin are worth checking. It weakens the activation of clopidogrel, its own level rises alongside clarithromycin, and it lowers the absorption of levothyroxine, so thyroid control can drift. Courses are meant to be short, and a long one is worth reassessing.

When to see a doctor

Cramps, muscle twitching or an irregular heartbeat, or lasting tingling with unexplained fatigue, can mean magnesium or B12 has fallen, and mean it is time to see a doctor. Heartburn that returns as soon as a course ends, difficulty swallowing, black stools or unplanned weight loss also mean see a doctor rather than repeat the packet.

Worth knowing

• Reassess the need for long courses
• Long use affects bone density

Markers to watch

• Magnesium
• Vitamin B12
• Ferritin
• Calcium, total

Nutrients affected

• vitaminB12 — depleted by (Hemoglobin, Homocysteine, Mean cell volume (MCV))
• magnesium — depleted by (Glucose, HOMA-IR, Magnesium)
• iron — absorption blocked with (Ferritin, Hematocrit, Hemoglobin)
• calcium — absorption blocked with (Calcium, ionized, Calcium, total, Ferritin)