NAPLEX Exam Dumps : North American Pharmacist Licensure Examination

It is not necessary that all the drugs get completely absorbed after oral administration. Most of them are incompletely absorbed. The extent of absorption varies from 5 to less than 100 % with oral ingestion of drugs.

Drugs which are too hydrophilic like atenolol are incompletely absorbed because the drug cannot cross the

lipid membrane due to high hydrophilic nature of the drug. Similarly, drugs which are too lipophilic like acyclovir are not soluble enough to cross the water layer adjacent to the cell. P-glycoprotein is an efflux transporter which is present in the enterocytes and it inhibits absorption of drug. It is also known as export transporter or reverse transporter. It has many drugs as its substrate. Grape juice in fact inhibits P-glycoprotein in the intestine thereby decreasing the efflux of drug from the cells by P-glycoprotein. Thus ingestion of grape juice may lead to significantly increased absorption of the drug.

The standard oral dose of alendronate in the treatment of osteoporosis is 70mg weekly – or 10mg per day.

The following NSAIDs belong to the propionic acid derivatives group - Ibuprofen - Ketoprofen - Naproxen - Fenoprofen - Flurbiprofen - Oxaprozin whereas piroxicam belongs to the class of Enolic acid derivative which also includes other agents like meloxicam and Nabumetone. They are non-selective COX inhibitors and act by preventing the production of certain prostaglandins.