Duodenal Ulcer
Active: 15 mg PO qDay for 4 weeks
Maintenance: 15 mg PO qDay
Gastric Ulcer
30 mg PO qDay for 8 weeks
NSAID-associated GU
Treatment: 30 mg PO qDay for 8 weeks
Prevention: 15 mg PO qDay for 12 weeks
Gastroesophageal Reflux Disease
15 mg PO qDay for 8 weeks
Erosive Esophagitis
30 mg PO qDay for 8-16 weeks
Maintenance: 15 mg PO qDay
Hypersecretory Condition (eg, Zollinger-Ellison Syndrome)
60 mg PO qDay initially; up to 180 mg q12hr used
If dose >120 mg/day PO, administer in divided doses q12hr
Helicobacter Pylori Infection
Triple therapy: Lansoprazole 30 mg + amoxicillin 1 g + clarithromycin 500 mg PO q12hr for 10-14 days
Dual therapy (clarithromycin resistant): Lansoprazole 30 mg + amoxicillin 1 g PO q8hr for 14 days
Penicillin allergy: Lansoprazole 30 mg + clarithromycin 500 mg + metronidazole 500 mg q12hr for 10-14 days
Heartburn
OTC product: 15 mg PO qDay for 14 days; may repeat q4MonthsAdministrationShould be taken on an empty stomach. Take before meals. ContraindicationsConcomitant use w/ rilpivirine and atazanavir.Special PrecautionsGastric malignancy should be ruled out. Hepatic impairment. Pregnancy and lactation. Monitoring Parameters Monitor Mg levels prior to initiation and periodically during prolonged use.Adverse Drug ReactionsIncreased risk of Clostridium difficile-associated diarrhoea (CDAD) and osteoporosis-related fractures. Diarrhoea, abdominal pain, nausea, vomiting, flatulence, constipation, headache, dry mouth, peripheral oedema, dizziness, sleep disturbances, fatigue, paraesthesia, arthralgia, myalgia, rash, pruritus, pancreatitis, glossitis, tremor, anorexia, restlessness, impotence, petechiae, purpura. Rare or very rarely, taste disturbance, stomatitis, hepatitis, jaundice, hypersensitivity reactions (e.g. bronchospasm), fever, depression, hallucinations, confusion, gynaecomastia, interstitial nephritis, hyponatraemia, hypomagnesaemia, blood disorders (e.g. leucopenia, leucocytosis, pancytopenia, thrombocytopenia), visual disturbances, sweating, photosensitivity, alopecia; colitis, increased serum cholesterol or triglycerides. Potentially Fatal: Anaphylaxis, Stevens-Johnson syndrome and toxic epidermal necrolysis.Drug InteractionsIncreased risk of hypomagnesaemia w/ diuretics and digoxin. May decrease plasma concentration of erlotinib, dasatinib and lapatinib. May decrease the bioavailability of itraconazole and ketoconazole. May increase plasma concentration of cilostazol and methotrexate. Reduced bioavailability w/ antacids and sucralfate. Potentially Fatal: May decrease serum levels and pharmacological effects of rilpivirine and atazanavir.Food InteractionAvoid St John’s wort as it may decrease the serum levels of lansoprazole.Pregnancy Category (US FDA)Category BStorageIntravenous: Store at 25°C. Oral: Store at 25°C.Mechanism of ActionLansoprazole is a substituted benzimidazole, and is also known as PPI due to its property to block the final step of acid secretion by inhibiting H+/K+ ATPase enzyme system in gastric parietal cell. Both basal and stimulated acid are inhibited. Onset: Oral: 1-3 hr. Duration: Oral: >1 day. Absorption: Rapidly absorbed from the GI tract (oral). Reduced absorption and bioavailability (approx 50%) w/ food. Bioavailability: ≥80%. Time to peak plasma concentration: Approx 1.5-2 hr. Distribution: Volume of distribution: 14-18 L. Plasma protein binding: Approx 97%. Metabolism: Hepatic metabolism via CYP2C19 isoenzyme to form 5-hydroxyl-lansoprazole and CYP3A4 to form lansoprazole sulfone. Excretion: Mainly in faeces via the bile; 15-30% of a dose via urine. Plasma elimination half-life: Approx 1-2 hr.