NAPLEX Exam Dumps : North American Pharmacist Licensure Examination

Metformin should be stopped when eGFR falls below 30. This is the only cutoff that is recommended for absolute discontinuing. If the eGFR falls between 30-44 while ontherapy, benefits and risks of discontinuing should be evaluated. New initiation is only recommended when eGFR >45.

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.

Diphenhydramine possesses anticholinergic properties. Xerostomia, or dry mouth, is a common side effect of anti-cholinergic medications, due to anti-muscarinic, parasympatholytic effects. Other adverse reactions may include: • Mydriasis with blurred vision, photophobia • Urinary retention • Constipation • Anhidrosis • Hyperthermia • Tachycardia • Altered mental status

A commonly referenced mnemonic for anti-cholinergic toxicity is “mad as a hatter, red as a beet, dry as a bone, hot as a hare, blind as a bat” to reflect confusion, flushing, dry mouth, hyperthermia and mydriasis, respectively.