McKenna's Pharmacology for Nursing, 2e

C

Appendix

Topical agents

T opical agents are intended for surface use only and are not meant for inges- tion or injection. They may be toxic if absorbed into the system, but they have several useful purposes when applied to the surface of the skin or mucous membranes. Some forms of drugs are prepared to be absorbed through the skin for systemic effects. These drugs may be prepared as transder- mal patches (e.g. glyceryl trinitrate, oestrogens, nicotine), which are designed to provide a slow release of the drug from the vehicle. Drugs prepared for this type of admin- istration are discussed with the specific drug in the text and are not addressed in this appendix.

Care considerations

Assessment: History and examination

■ ■ Screen for the presence of any known allergy to the drug , which would be a contraindication to its use. ■ ■ Include screening for baseline status before beginning therapy and for any potential adverse effects . Assess the following: condition of area to be treated. Implementation ■ ■ Ensure proper administration of the drug to provide best therapeutic effect and least adverse effects as follows : –– Apply sparingly. Some preparations come with applicators, some should be applied while wearing protective gloves and others are dropped onto the site with no direct contact. Consult information regarding the individual drug being used for specific procedures. –– Do not use with open wounds or broken skin, which could lead to systemic absorption and toxic effects . –– Avoid contact with the eyes, which could be injured by the drug . –– Do not use with occlusive dressings, which could increase the risk of systemic absorption. ■ ■ Monitor the area being treated to evaluate drug effects on the condition being treated . ■ ■ Provide comfort measures to help the person tolerate drug effects (e.g. analgesia as needed for local pain, itching). ■ ■ Provide teaching to enhance knowledge about drug therapy and promote compliance with the drug regimen : –– Teach the person the proper administration technique for the topical agent ordered. –– Caution the person that transient stinging or burning may occur. –– Instruct the person to report severe irritation, allergic reaction or worsening of the condition being treated. Evaluation ■ ■ Monitor response to the drug (improvement in condition being treated).

Therapeutic actions and indications Topical agents are used to treat a variety of disorders in a localised area. Table C describes the usual uses for the many different types of topical agents. Because these drugs are designed for topical application, they are minimally absorbed systemically and, if used properly, should have minimal systemic effects. Contraindications and cautions The use of topical agents is contraindicated in cases of allergy to the drugs and in the presence of open wounds or abrasions, which could lead to the systemic absorption of the drugs . Caution should be used during pregnancy if there is any possibility that the agent might be absorbed . Caution should also be used in the presence of any known allergy to the vehicles of prepa- ration (creams, lotions) . Adverse effects Because these drugs are not intended to be absorbed systemically, the adverse effects usually associated with topical agents are local effects, including local irritation, stinging, burning or dermatitis. Toxic effects are associ- ated with inadvertent systemic absorption.