Ординатура / Офтальмология / Английские материалы / Oxford American Handbook of Ophthalmology_Tsai, Denniston, Murray_2011

696 CHAPTER 22 Therapeutics

Ocular medication: general

All doses and frequencies of administration are based on a healthy adult. All medications should be checked in the Physician Drug Reference Guide for accuracy, side effects, contraindications, interactions, and appropriate age-adjusted dosing.

When considering patients’ medication, it is important to check what they are actually taking rather than what you or anybody else think they are taking. Consider the issue of adherence and compliance, particularly when about to treat a suboptimal response with additional medications or more frequent regimens. For more invasive procedures (e.g., injections), formal consent should be taken.

Topical

Only around 1–10% of most topical agents are absorbed into the eye. Absorption is dependent on ocular contact time, drug concentration, and tissue permeability. Small lipophilic drugs pass through the cornea, whereas larger hydrophilic drugs are generally absorbed through conjunctiva and sclera.

Topical agents may be in aqueous solution (comfortable, no blurring but very short ocular contact time), in suspension (longer ocular contact time, but bottle must be shaken and may cause FB sensation), or in ointment (liquefy at body temperature, longest ocular contact time, but blurs vision).

Technique

•Ensure that patients know how to instill any topical medication and that they can physically manage it.

•If reliable self-administration is not possible, ensure that there is somebody (even a visiting nurse) who can assist them.

•Consider ways of making it easier, e.g., lying flat, mirror positioning, or eyedrop dispensers. Smaller bottles and single-use vials tend to be particularly difficult for the frail and elderly patient.

•Leave at least 5 min between instilling topical medications.

•Keep the eye closed and put pressure over the lacrimal sac for 1–2 min to try to increase ocular and reduce systemic absorption.

Medications

This includes most ophthalmic medications listed on the following pages (Tables 22.4–22.17).

Subconjunctival injection

Technique

•Ensure adequate anesthesia (e.g., a couple of drops of proparacaine).

•Under direct vision (or slit lamp or operating microscope), lift an area of conjunctiva to form a small bleb and slowly inject (sharp needle).

Medications

This route is most commonly used for postoperative injections of corticosteroids and antibiotics, but it may be used in acute anterior segment inflammation to deliver mydriatics and corticosteroids.

698 CHAPTER 22 Therapeutics

Topical antibiotics

Table 22.4 Antibacterial agents

Frequency: recommendation for antibacterial eyedrops is that they are administered at least every 2 hours, then reduce frequency as infection is controlled and continue for 48 hours after healing. For ointments it is recommended that they be used at night (with drops used during the day) or 3–4x/day if used alone.

TOPICAL ANTIBIOTICS 699

Table 22.5 Topical antifungal agents

Table 22.6 Antiviral agents

Frequency: recommend continuing at 5x/day for at least 3 days after healing for acyclovir, and 3x/day for a week after healing for gancyclovir. The acyclovir and gancyclovir ophthalmological formulations are only available in Europe.

700 CHAPTER 22 Therapeutics

Topical anti-inflammatory agents

Corticosteroids

Table 22.7 Corticosteroids

Frequency: potency and frequency of corticosteroids should be titrated against degree of inflammation to achieve control while minimizing side effects.

Table 22.8 Corticosteroid/antibiotic combinations

TOPICAL ANTI-INFLAMMATORY AGENTS 701

Antihistamines and other anti-inflammatory agents

Table 22.9 Topical antihistamines and other antiallergy agents

Generic Pres-free Frequency Brand name

Anti-histamine

Other

Table 22.10 Other topical anti-inflammatory agents (NSAID type)

702 CHAPTER 22 Therapeutics

Topical glaucoma medications

B-blockers

Table 22.11 β-blockers

Prostaglandin analogues

Table 22.12 Prostaglandin analogues

Sympathomimetics

Table 22.13 Sympathomimetics

TOPICAL GLAUCOMA MEDICATIONS 703

Carbonic anhydrase inhibitors

Table 22.14 Carbonic anhydrase inhibitors

Miotics

Table 22.15 Miotics

Combination drops

Table 22.16 Combinations with timolol

704 CHAPTER 22 Therapeutics

Topical mydriatics

Mydriatics

Table 22.17 Mydriatics and cycloplegics

SYSTEMIC MEDICATION: GLAUCOMA 705

Systemic medication: glaucoma

Systemic medication may be required to lower intraocular pressure in the acute setting (e.g., acute angle closure glaucoma) or if topical treatment alone has failed. It is also commonly used prophylactically post-procedure (e.g., acetazolamide after cataract surgery). Acetazolamide may also be used in the treatment of raised intracranial pressure secondary to idiopathic intracranial hypertension.

Table 22.18 Systemic glaucoma medications