Prevacid is a brand name for the proton-pump inhibitor (PPI) lansoprazole. It belongs to the digestive health therapeutic class and is available in pill form in strengths of 15 mg and 30 mg. In Hong Kong, Prevacid is a prescription-only medication regulated by the Department of Health. The active ingredient, lansoprazole, works by reducing stomach acid production, which helps manage a variety of acid-related gastrointestinal conditions.
Lansoprazole belongs to the proton-pump inhibitor family. It blocks the H⁺/K⁺-ATPase enzyme-commonly called the gastric proton pump-located on the parietal cells of the stomach lining. By inhibiting this enzyme, lansoprazole prevents the final step of gastric acid secretion, leading to a sustained reduction in both basal and stimulated acid output.
Lansoprazole is well absorbed after oral administration, with a bioavailability of roughly 80 % in fasting conditions. It is metabolized primarily by the liver enzyme CYP2C19 (and to a lesser extent CYP3A4) and eliminated in the urine and feces.
Prevacid is approved in Hong Kong for the following indications:
These uses are supported by regulatory approvals and clinical guidelines that recognize lansoprazole’s efficacy in reducing gastric acidity and promoting mucosal healing.
Evidence from peer-reviewed studies suggests additional uses that are not formally approved in Hong Kong:
Disclaimer: Off-label use requires medical supervision and individualized risk assessment. These applications have not received regulatory approval in Hong Kong.
Absolute contraindications
Relative contraindications
Special populations
Major:
Clopidogrel: Lansoprazole can reduce conversion to its active metabolite via CYP2C19 inhibition, potentially diminishing antiplatelet effect.
Warfarin: May increase INR; monitor coagulation parameters closely.
Moderate:
Methotrexate (high-dose): Decreased renal clearance; monitor serum levels.
Digoxin: Slight increase in serum concentrations; observe for toxicity.
CYP enzyme considerations: Lansoprazole is a substrate of CYP2C19; inhibitors (e.g., fluconazole) can raise plasma concentrations, while inducers (e.g., rifampin) may lower them.
General advice: Patients should disclose all medications, supplements, and herbal products to their healthcare provider before starting Prevacid.
Standard adult dosing:
GERD or ulcer healing: 15 mg or 30 mg once daily, taken before the first meal of the day.
H. pylori eradication regimens: Typically 30 mg once daily for 7-14 days together with appropriate antibiotics.
Special populations:
Renal or hepatic impairment: No routine dose modification, but clinicians may adjust based on clinical response.
Elderly: Start with the lowest effective dose (15 mg) to assess tolerance.
Administration: Swallow the pill whole with a glass of water. Do not crush, chew, or split the tablet, as this may affect its delayed-release properties.
Missed dose: Take the missed dose as soon as remembered unless it is near the time of the next scheduled dose; then skip the missed dose and resume the regular schedule. Do not double the dose.
Overdose: Symptoms may include confusion, drowsiness, blurred vision, fast heartbeat, or seizures. Seek emergency medical care; treatment is supportive.
Discontinuation: For short-term therapy, abrupt cessation is generally safe. For long-term use, tapering is recommended to reduce rebound acid hypersecretion, especially after more than several weeks of continuous therapy.
This article provides educational information about Prevacid and is not a substitute for professional medical advice. Treatment decisions, including the use of unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.
Take the missed dose as soon as you remember, unless it is almost time for your next scheduled dose. In that case, skip the missed dose and resume your regular dosing schedule. Do not take two doses at once.
Concurrent use of multiple PPIs or H2-receptor antagonists is generally unnecessary and may increase the risk of side effects. Discuss any combination therapy with your healthcare provider.
Most gastric or duodenal ulcers begin to heal within 4-6 weeks of daily lansoprazole therapy, though complete healing may require up to 8 weeks depending on ulcer size and patient factors.
Both strengths contain the same active ingredient, lansoprazole, but the 30 mg tablet provides a higher dose per administration, which may be required for more severe acid-related conditions.
Long-term PPI use can lower serum magnesium and vitamin B12 levels, potentially altering routine laboratory values. Periodic monitoring is advisable for patients on prolonged therapy.
Prevacid is classified as Category C for pregnancy in many jurisdictions, meaning risk cannot be ruled out. It should only be used if the expected benefit justifies potential risk to the fetus, and always under medical supervision.
Antacids containing aluminum or magnesium may be taken several hours after a lansoprazole dose without affecting its efficacy. They can provide immediate symptom relief while the PPI works.
Symptoms may include rash, itching, swelling (especially of the face or throat), severe dizziness, or difficulty breathing. Seek emergency medical attention if any of these occur.
Keep the tablets in their original container, protected from heat and moisture. If traveling internationally, ensure you have a copy of the prescription and comply with Hong Kong customs regulations regarding medication import.
