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Prevacid: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Sep 8, 2021.

1. How it works

  • Prevacid is a brand (trade) name for lansoprazole. Lansoprazole reduces the production of stomach acid by irreversibly blocking the actions of an enzyme responsible for acid production, called H+/K+ ATPase (also known as the gastric proton pump). The proton pump is located in the parietal cells of the stomach wall. Both baseline gastric acid secretion and stimulated gastric acid secretion are affected; the degree that they are affected to depends on the dose of lansoprazole.
  • This allows damaged tissue in the esophagus, stomach, and duodenum to heal, and reduces the risk of new ulcers forming. Prevacid may also be used to treat other gastrointestinal disorders characterized by excessive acid secretion.
  • Prevacid belongs to the class of medicines known as proton pump inhibitors (PPIs).

2. Upsides

  • Used for the short-term treatment of duodenal ulcers (up to four weeks) and gastric ulcers (up to eight weeks).
  • May also be used to heal ulcers associated with NSAID use and to reduce the risk of ulcer occurrence in people using NSAIDs.
  • May be considered for the short-term treatment of gastroesophageal reflux disease (GERD) (also known as heartburn) and erosive esophagitis (a severe inflammation of the lining of the esophagus- the tube that carries food from the mouth to the stomach).
  • Prevacid capsules may be used to maintain healing of duodenal ulcers and erosive esophagitis.
  • May be used in addition to antibiotics to eradicate Helicobacter pylori (a bacteria found in the gut that is linked to gastric ulcers).
  • Useful in the treatment of hypersecretory conditions such as Zollinger-Ellison syndrome.
  • No dosage adjustment is needed in people with kidney disease; however, a dosage reduction should be considered in those with severe liver disease.
  • Prevacid is available as a delayed-release capsule, in a 15mg and 30mg strength, and delayed-release orally disintegrating tablets.
  • Prevacid is available as a generic under the name lansoprazole.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Diarrhea, abdominal pain, nausea, headache, and constipation have been the most common side effects reported. May also interfere with some laboratory tests.
  • PPIs (including Prevacid) have been associated with an increased risk of osteoporosis-related fractures of the hip, wrist, or spine. People on high-dose or long-term therapy are more at risk.
  • Has also been associated with other conditions such as lupus erythematosus and magnesium deficiency.
  • Prolonged treatment (greater than 24-36 months) may cause vitamin B12 deficiency. The risk is greater in women, people aged less than 30, and with higher dosages.
  • Administration of PPIs (such as Prevacid) has been associated with acute interstitial nephritis, a severe inflammation of the kidneys. May occur on medication initiation or at any point of therapy. Symptoms include fever, rash, and generalized aches and pains. Discontinue Prevacid and seek medical advice.
  • Has been associated with a greater risk of Clostridium difficile-associated diarrhea. See your doctor if you develop diarrhea that does not improve.
  • May not be suitable for some people including those with liver disease, low magnesium levels, lupus, phenylketonuria, pregnant or breastfeeding, or with allergies to PPIs.
  • Some studies have suggested PPIs (such as Prevacid) are associated with a higher risk of stomach cancer and kidney disease.
  • May interact with some other medications including methotrexate and sometimes warfarin. Prevacid can also reduce the absorption of drugs that are dependant on a certain gastric pH for their absorption.
  • There are no adequate or well-controlled studies of Prevacid during pregnancy but animal studies have shown changes in bone morphology in the offspring of rats dosed throughout pregnancy and lactation. Use only if potential benefits justify the risk. It is unknown how Prevacid affects a breastfeeding infant.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Prevacid decreases stomach acid production which promotes the healing of gastric and duodenal ulcers and other inflamed gastrointestinal tissue areas. Prevacid, like other PPIs, should only be used short-term.

5. Tips

  • Take as directed by your doctor (usually once or twice daily). Do not take for longer than directed or share your capsules.
  • Take Prevacid capsules before eating (usually 30 minutes before food).
  • Swallow delayed-release Prevacid capsules whole; do not crush or chew.
  • Delayed-release capsules may be opened and the contents sprinkled on a tablespoon of applesauce, ENSURE pudding, cottage cheese, yogurt, or strained pears and swallowed immediately. Alternatively, 60mL of apple, orange, or tomato juice may be used.
  • Allow the orally disintegrating tablet to dissolve in your mouth, do not crush, chew, or break it. The tablet should dissolve within a minute.
  • See your doctor if you develop any unexplained fever, rash (particularly one that gets worse after you have been in the sun), new or worsening joint pain, persistent diarrhea or generalized aches and pains.
  • Also see your doctor if you develop any muscle cramps, spasms, or weakness; jitteriness; abnormal heartbeat; dizziness; seizures; or any other symptoms of concern.
  • Tell your doctor if you are breastfeeding, pregnant, or intending to become pregnant because Prevacid may not be suitable for you.

6. Response and effectiveness

  • Peak plasma levels of Prevacid are reached within 1.7 hours of oral administration. Prevacid does not accumulate with multiple dosing.
  • A response to Prevacid does not preclude the presence of gastric cancer. Further investigations should be conducted if symptoms recur on discontinuation, or other worrying symptoms (such as blood in the stools) occur.

7. Interactions

Medicines that interact with Prevacid may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Prevacid. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Prevacid include:

  • aminophylline or theophylline
  • astemizole
  • bisphosphonates, such as alendronate, etidronate, or risedronate
  • clopidogrel
  • digoxin
  • HIV medications (eg, atazanavir, indinavir, ritonavir, or saquinavir)
  • methotrexate
  • medications that rely on a certain gastric pH for absorption, such as ampicillin, bisacodyl, dasatinib, erlotinib, iron salts, ketoconazole/itraconazole, mycophenolate mofetil, or nilotinib
  • medications that affect either CYP3A4 or CYP2C19 hepatic enzymes, such as erythromycin, fluconazole, fluvoxamine, itraconazole, ketoconazole, or voriconazole
  • sucralfate
  • tacrolimus
  • warfarin.

In addition, Prevacid may affect some diagnostic tests, for example, those for neuroendocrine tumors or the secretin stimulation test. There have also been reports of false positive urine screening tests for tetrahydrocannabinol (THC) in patients receiving PPIs, such as Prevacid.

Note that this list is not all-inclusive and includes only common medications that may interact with Prevacid. You should refer to the prescribing information for Prevacid for a complete list of interactions.


Prevacid (lansoprazole) [Package Insert] 05/2021. Takeda Pharmaceuticals America, Inc.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Prevacid only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2022 Revision date: September 8, 2021.