Prevacid NapraPAC

Uses

Lansoprazole is used for:

• Short term treatment of active duodenal ulcer
• Maintenance of healed duodenal ulcers
• Short term treatment of active benign gastric ulcers
• Short term treatment of active erosive esophagitis
• Maintenance of healing of erosive esophagitis
• Pathological hypersecretory conditions including Zollinger- Ellison Syndrome
• H. pylori eradication to reduce the risk of duodenal ulcer recurrence

Prevacid NapraPAC is also used to associated treatment for these conditions: Gastro-esophageal Reflux Disease (GERD), Gastrointestinal Bleeding, Helicobacter Pylori Infection, Peptic Ulcer Disease, Hypersecretory conditions

How Prevacid NapraPAC works

As a PPI, lansoprazole is a prodrug and requires protonation via an acidic environment to become activated. Once protonated, lansoprazole is able to react with cysteine residues, specifically Cys813 and Cys321, on parietal H+,K+-ATPase resulting in stable disulfides. PPI's in general are able to provide prolonged inhibition of acid secretion due to their ability to bind covalently to their targets.

Dosage

Prevacid NapraPAC dosage

Benign gastric ulcer: 30 mg daily in the morning for 8 weeks.

Duodenal ulcer: 30 mg daily in the morning for 4 weeks; maintenance 15 mg.

NSAID-associated duodenal or gastric ulcer: 15-30 mg daily for 4 weeks, followed by a further 4 weeks if not fully healed.

Zollinger-Ellison syndrome (and other hypersecretory conditions): Initially 60 mg once daily adjusted according to response; daily doses of 120 mg or more is given in two divided doses.

Gastroesophageal reflux disease: 30 mg daily in the morning for 4 weeks, followed by a further 4 weeks if not fully healed; maintenance 15-30 mg daily.

Acid-related dyspepsia: 15-30 mg daily in the morning for 2-4 weeks.

Side Effects

Severe or irreversible adverse effects: The possible induction of carcinoid tumors by profound acid suppression, and a rise in serum gastrin may occur. There is a rise in serum gastrin levels in the first 3 months of treatment, which are then maintained though at a lower level than those found in pernicious anaemia. Long term treatment with a proton pump inhibitor in patients with Helicobacter pylori infection may accelerate the development of atrophic gastritis.

Symptomatic adverse effect: Dose dependent diarrhoea occurs with an incidence of about 4% at 30 mg per day, rising to 8% at 60 mg per day. Headache occurs in 2-3% of treated patients

Toxicity

The most commonly reported adverse events occurring more frequently in lansoprazole treated patients compared to placebo include abdominal pain, constipation, diarrhea, and nausea. There is a case report of toxic epidermal necrolysis (TEN), which is a rare but very serious cutaneous reaction, caused by lansoprazole. The previously healthy patient presented with symptoms of TEN 15 days after starting lansoprazole to manage peptic disease. Although the use of PPI's is rarely associated with TEN, causation should be considered if a patient presents with TEN shortly after newly commencing a PPI.

In a single case report, a patient ingested 600 mg of lansoprazole and did not experience any adverse effects or symptoms of overdose. Overall, lansoprazole is well tolerated with relatively few adverse effects.

Lansoprazole is classified as Pregnancy Category B. Although there are animal studies that suggest lansoprazole does not cause harm to the fetus, there is still a paucity of human data. Hence, lansoprazole should only be administered to pregnant women if other options with more safety data have been exhausted.

It is unknown if lansoprazole is excreted in human breast milk. It is worth mentioning that lansoprazole has been used safely in infants, and is therefore likely safe to use during breastfeeding.

Precaution

Gastric malignancy should be ruled out. Hepatic impairment. Pregnancy and lactation.

Interaction

Lansoprazole appears to be a selective inhibitor of the cytochrome P-450 monooxygenase system; there may be an effect on hepatic clearance, but there have been no reports to date of clinically relevant interactions. There is some uncertainty over the effect of Lansoprazole on the oral combined contraceptive pill. Further assessment is currently underway. Physiological changes similar to those found with Omeprazole are likely to take place because of the reduction in gastric acid, which is likely to influence the bacterial colonization of the stomach and duodenum and also vitamin B12 absorption.

Volume of Distribution

The apparent volume of distribution of lansoprazole is 0.4 L/kg.

Elimination Route

The oral bioavailability of lansoprazole is reported to be 80-90% and the peak plasma concentration(Cmax) is achieved about 1.7 hours after oral dosing. Food reduces the absorption of lansoprazole (both Cmax and AUC are reduced by 50-70%); therefore, patients should be instructed to take lansoprazole before meals.

Half Life

One source reports the half life of lansoprazole to be 0.9 - 1.6 hours, while another source cites 0.9 - 2.1 hours. The general consensus is that lansoprazole has a short half life and is approximately 2 hours or less. These numbers may be misleading since it suggests that lansoprazole has a short duration of action when in practice, lansoprazole can effectively inhibit acid secretion for ~24 hours due to it's mechanism of action.

Clearance

The reported clearance of lansoprazole is 400-650 mL/min.

Elimination Route

A reported 14-23% of a lansoprazole is eliminated in the urine with this percentage range including both conjugated and unconjugated hydroxylated metabolites.

Pregnancy & Breastfeeding use

Lansoprazole should be avoided in pregnancy unless there are compelling reasons.

Contraindication

Lansoprazole is contraindicated in patients with known hypersensitivity to any component of the formulation.

Special Warning

Neonates:There is no relevant human data. The drug is not recommended for use with neonates.

Children: The youngest person to have received Lansoprazole in clinical trials was 13 years old.

The Elderly: No problems have been encoun- tered in clinical use and there has been no increase in adverse drug reaction in the elderly.

Storage Condition

Store at 25° C.

Innovators Monograph

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