Administration, drugs oral route

All routes of drug administration can affect ocular structures and functions. OADRs have been associated with topical ophthalmic administrations as well as local injections. Systemically, oral drug administration has been implicated most frequently in the development of OADRs. However, parenteral as well as inhaled or nasally applied drugs have also produced OADRs. Topical application to the skin, particularly if it is abraded or burned, may result in sufficient systemic absorption to lead to ocular side effects. Dermatologic use of antibiotics has resulted in ocular hypersensitivity reactions. 

Drug administration route An obstructed catheter connection pin discovered during intrathecal baclofen pump exchange caused increased intrathecal drug dosage requirements and eventually oral baclofen was required [51 ]. 

Among the various systemic drug delivery routes, oral administration is considered to be the most popular. Oil-in-water emulsions are already considered very interesting formulations for oral drug administration of poorly... 

The oral route is the most frequent route of drug administration and rarely causes physical discomfort in patients. Oral drug forms include tablets, capsules, and liquids. Some capsules and tablets contain sustained-release drag s, which dissolve over an extended period of time. Administration of oral dru is relatively easy for patients who are alert and can swallow. 

For the majority of drugs, the preferred administration route is by oral ingestion which requires good intestinal absorption of drug molecules. Intestinal absorption is usually expressed as fraction absorbed (FA), expressing the percentage of initial dose appearing in a portal vein [15]. 

Opioids maybe administered in a variety of routes including oral (tablet and liquid), sublingual, rectal, transdermal, transmucosal, intravenous, subcutaneous, and intraspinal. While the oral and transdermal routes are most common, the method of administration is based on patient needs (severity of pain) and characteristics (swallowing difficulty and preference). Oral opioids have an onset of effect of 45 minutes, so intravenous or subcutaneous administration maybe preferred if more rapid relief is desired. Intramuscular injections are not recommended because of pain at the injection site and wide fluctuations in drug absorption and peak plasma concentrations achieved. More invasive routes of administration such as PCA and intraspinal (epidural and intrathecal) are primarily used postoperatively, but may also be used in refractory chronic pain situations. PCA delivers a self-administered dose via an infusion pump with a preprogrammed dose, minimum dosing interval, and maximum hourly dose. Morphine, fentanyl, and hydromorphone are commonly administered via PCA pumps by the intravenous route, but less frequently by the subcutaneous or epidural route. 

The transdermal route of drug administration offers several advantages over other methods of delivery. For some cases, oral delivery may be contraindicated, or the drug may be poorly absorbed. This would also include situations for which the drug undergoes a substantial first-pass effect [173] and systemic therapy is desired. 

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