Commonly Used Eye Medications
The following is intended to serve as a concise formulary of commonly used ophthalmic drugs. Product leaflets, package inserts, and standard pharmacology and toxicology texts should be consulted for more detailed information.
Topical anesthetics are useful for diagnostic and therapeutic procedures, including tonometry, removal of foreign bodies or sutures, gonioscopy, corneal or conjunctival scraping, and minor surgical operations on the cornea and conjunctiva. Cataract (phacoemulsification) surgery is increasingly being carried out under topical anesthesia, supplemented if necessary by (intracameral) injection of local anesthetic into the anterior chamber (see later in the chapter), or oral or intravenous sedation. One or two instillations of topical anesthetic are usually sufficient, but the dosage may be repeated during the procedure.
Proparacaine, tetracaine, and benoxinate are the most commonly used topical anesthetics. For practical purposes, they can be said to have equivalent anesthetic potency.Lidocaine 3.5% gel (Akten) and cocaine 1%–4% solution are also used for topical anesthesia.
Note:Topical anesthetics should never be prescribed for home use, since prolonged application may cause corneal complications and mask serious ocular disease.
Preparation: Solution, 0.5%. A combined preparation of proparacaine and fluorescein is available as Fluoracaine.
Dosage: 1 drop and repeat as necessary.
Onset and duration of action: Anesthesia begins within 20 seconds and lasts 10–15 minutes.
Comment: Least irritating of the topical anesthetics and most suitable for corneal scraping for microbiological cultures.
Preparations: Solution, 0.5% and ointment, 0.5%.
Dosage: 1 drop and repeat as necessary.
Onset and duration of action: Anesthesia occurs within 1 minute and lasts for 15–20 minutes.
Comment: Stings considerably on instillation.
Preparation (as Fluress): Solution, 0.4%.
Dosage: 1 drop and repeat as necessary.
Onset and duration of action: Anesthesia begins within 1 or 2 minutes and lasts for 10–15 minutes.
Comment: Benoxinate 0.4% and fluorescein 0.25% (Flurate, Fluress) may be used prior to applanation tonometry.
Lidocaine, procaine, and mepivacaine are commonly used local anesthetics for eye surgery. Longer-acting agents such as bupivacaine and etidocaine are often mixed with other local anesthetics to prolong the duration of effect. Local anesthetics are extremely safe when used with discretion, but the physician must be aware of the potential systemic toxic action when rapid absorption occurs from the site of the injection, with excessive dosage, or following inadvertent intravascular injection.
The addition of hyaluronidase encourages spreading of the anesthetic and shortens the onset to as little as 1 minute. For these reasons, hyaluronidase is commonly used in peribulbar injections prior to cataract extraction. Injectable anesthetics are used by ophthalmologists most commonly in older patients, who may be susceptible to cardiac arrhythmias; therefore, l-epinephrine should not be used in concentrations greater than 1:200,000.
Owing to its rapid onset and longer action (1–2 hours), lidocaine has become the most commonly used local anesthetic. It is approximately twice as potent as procaine. Up to 30 mL of 1% solution, without epinephrine, may be used safely. In cataract surgery, 10 mL is usually sufficient for peribulbar or sub-Tenon’s injections. The maximal safe dose is 4.5 mg/kg without epinephrine and 7 mg/kg with epinephrine. Intracameral preservative-free lidocaine 1% solution is employed for anesthesia in cataract surgery.
Preparations: Solution, 1%, 2%, and 10%.
Dosage: Approximately 50 mL of a 1% solution can be injected without causing systemic effects. The maximal safe dose is 10 mg/kg.
Duration of action: 45–60 minutes.
Preparations: Solution, 1%, 1.5%, 2%, and 3%.
Dosage: Infiltration and nerve block, up to 20 mL of 1% or 2% solution.
Duration of action: Approximately 2 hours.
Comment: Carbocaine is similar to lidocaine in potency. It is usually used in patients who are allergic to lidocaine. The maximum safe dose is 7 mg/kg.
Preparations: Solution, 0.25%, 0.5%, and 0.75%.
Dosage: The 0.75% solution has been used most frequently in ophthalmology. The maximal safe dose in an adult is 250 mg with epinephrine and 200 mg without epinephrine. Bupivacaine is frequently mixed with an equal amount of lidocaine.
Onset and duration of action: The onset of action is slower than that of lidocaine, but it persists much longer (up to 6–10 hours).
Preparations: Solution, 1% and 1.5%.
Dosage: The maximal safe dose of etidocaine is 4 mg/kg without epinephrine and 5.5 mg/kg with epinephrine. This agent is frequently mixed with lidocaine for local anesthesia in ophthalmic surgery.
Onset and duration of action: The onset of action is slower than that of lidocaine, but more rapid than that of bupivacaine. The duration of action is approximately twice as long as that of lidocaine (4–8 hours).
Mydriatics and cycloplegics both dilate the pupil. In addition, cycloplegics cause paralysis of accommodation (patient unable to see near objects, for example, printed words). They are commonly used drugs in ophthalmology, singly and in combination. Their prime uses are (1) for dilating the pupils to facilitate ophthalmoscopy; (2) for paralyzing the muscles of accommodation, particularly in young patients, as an aid in refraction; and (3) for dilating the pupil and paralyzing the muscles of accommodation in uveitis to prevent synechia formation and relieve pain and photophobia. Since mydriatics and cycloplegics both dilate the pupil, they should be used with extreme caution in eyes with narrow anterior chamber angles since either a mydriatic or a cycloplegic can cause angle-closure glaucoma in such eyes.
Phenylephrine is a mydriatic with no cycloplegic effect.
Preparations: Solution, 0.12%, 2.5%, and 10%.
Dosage: 1 drop and repeat in 5–10 minutes.
Onset and duration of action: The effect usually occurs within 30 minutes after instillation and lasts 2–3 hours.
Comment: Phenylephrine is used both singly and with cycloplegics to facilitate ophthalmoscopy, in treatment of uveitis, and to dilate the pupil prior to cataract surgery. The 10% solution should not be used in newborn infants, in cardiac patients, or in patients receiving reserpine, guanethidine, or tricyclic antidepressants, because of increased susceptibility to the vasopressor effects.
Preparations: Solution, 0.5%–3%; ointment, 0.5% and 1%.
Dosage: For refraction in children, instill 1 drop of 0.25%−0.5% solution in each eye twice a day for 1 or 2 days before the examination and then 1 hour before the examination; ointment, ¼-in ribbon twice a day for 2 days prior to examination.
Onset and duration of action: The onset of action is within 30–40 minutes. A maximal effect is reached in about 2 hours. The effect lasts for up to 2 weeks in a normal eye, but in the presence of acute inflammation, the drug must be instilled 2 or 3 times daily to maintain its effect.
Toxicity: Atropine drops must be used with caution to avoid toxic reactions resulting from systemic absorption. Restlessness and excited behavior with dryness and flushing of the skin of the face, dry mouth, fever, inhibition of sweating, and tachycardia are prominent toxic symptoms, particularly in young children.
Comment: Atropine is an effective and long-acting cycloplegic. In addition to its use for cycloplegia in children, atropine is applied topically 2 or 3 times daily in the treatment of iritis. It is also used to maintain a dilated pupil after intraocular surgical procedures.
Preparation: Solution, 0.25%.
Dosage: 1 drop 2 or 3 times daily.
Onset and duration of action: Cycloplegia occurs in about 40 minutes and lasts for 3–5 days when scopolamine is used as an aid to refraction in normal eyes. The duration of action is much shorter in inflamed eyes.
Toxicity: Scopolamine occasionally causes dizziness and disorientation, mainly in older people.
Comment: Scopolamine is an effective cycloplegic. It is used in the treatment of uveitis, in refraction of children, and postoperatively.
Preparations: Solution, 2% and 5%.
Dosage: For refraction, 1 drop in each eye and repeat 2 or 3 times at intervals of 10–15 minutes.
Onset and duration of action: Maximal cycloplegic effect lasts for about 3 hours, but complete recovery time is about 36–48 hours. In certain cases, the shorter action is an advantage over scopolamine and atropine.
Toxicity: Sensitivity and side effects associated with the topical instillation of homatropine are rare.
Comment: Homatropine is an effective cycloplegic often used in the treatment of uveitis.
Preparations: Solution, 0.5%, 1%, and 2%.
Dosage: For refraction, 1 drop in each eye and repeat after 10 minutes.
Onset and duration of action: The onset of dilatation and cycloplegia is within 30–60 minutes. The duration of action is less than 24 hours. Comment: Cyclopentolate is more popular than homatropine and scopolamine in refraction because of its shorter duration of action. Occasionally, neurotoxicity may occur, manifested by incoherence, visual hallucinations, slurred speech, and ataxia. These reactions are more common in children.
Preparations: Solution, 0.5% and 1%; 0.25% with 1% hydroxamphetamine hydrobromide (Paremyd).
Dosage: 1 drop of 1% solution 2 or 3 times at 5-minute intervals.
Onset and duration of action: The time required to reach the maximal cycloplegic effect is usually 20–25 minutes, and the duration of this effect is only 15–20 minutes; therefore, the timing of the examination after instilling tropicamide is important. Complete recovery requires 5–6 hours.
Comment: Tropicamide is an effective mydriatic with weak cycloplegic action and is therefore most useful for ophthalmoscopy.
Preparations: Solution, 0.2% cyclopentolate hydrochloride and 1% phenylephrine hydrochloride.
Dosage: 1 drop every 5–10 minutes for 2 or 3 doses. Pressure should be applied over the nasolacrimal sac after drop instillation to minimize systemic absorption.
Onset and duration of action: Mydriasis and some cycloplegia occur within the first 3–6 minutes. The duration of action is usually less than 24 hours. This drug combination is of particular value for pupillary dilation in examination of premature and small infants.
The dose and frequency of administration of therapy should be individualized according to measurements of intraocular pressure, the minimum treatment being used that sufficiently controls the intraocular pressure to adequately prevent optic nerve damage.
The prostaglandin analogs reduce intraocular pressure by increasing outflow of aqueous, mainly via the uveoscleral pathway. Each agent may be used alone or in combination with other types of glaucoma medication, but additive effect is more likely when used in conjunction with agents that reduce aqueous production.
Toxicity: All preparations are associated with increased brown pigmentation of the iris, eyelash growth, hyperpigmentation of periorbital skin, conjunctival hyperemia, punctate epithelial keratopathy, and foreign body sensation. In addition, they may aggravate ocular inflammation and have been associated with the development of cystoid macular edema.
Preparation: Solution, 0.005%.
Dosage: 1 drop daily at night.
Preparation: Solution, 0.03%.
Dosage: 1 drop daily at night.
Preparation: Solution, 0.004%.
Dosage: 1 drop daily.
(Not available in the United States)
Preparation: Solution, 0.0015% (preservative-free)
Dosage: 1 drop daily at night.
(Not available in the United States)
Preparation: Solution, 0.15%.
Dosage: 2 drops daily.
Beta-adrenergic blocking agents reduce intraocular pressure by suppressing aqueous production.
Toxicity: All preparations, particularly the non-selective agents, have the potential to cause adverse systemic effects (see discussion in separate section), especially bronchoconstriction and bradycardia but also depression, confusion, and fatigue. They are contraindicated in patients with obstructive airways disease, either asthma or chronic obstructive pulmonary disease (COPD), although betaxolol with its relative β1 receptor selectivity is safer in this context, and in patients with cardiac conduction defects.
Preparations: Solution, 0.25% and 0.5%; gel, 0.25% and 0.5%.
Dosage: 1 drop of 0.25% or 0.5% in each eye once or twice daily if needed. One drop of gel once daily.
Comment: Non-selective beta-blocker
Preparations: Solution, 0.25% and 0.5%.
Dosage: 1 drop once or twice daily.
Comment: Non-selective beta-blocker, comparable in efficacy to timolol.
Preparation: Solution, 0.3%.
Dosage: 1 drop once or twice daily.
Comment: Non-selective beta-blocker, comparable in efficacy to timolol.
Preparation: Solution, 1%.
Dosage: 1 drop once or twice daily.
Comment: Non-selective beta-blocker, comparable in efficacy to timolol.
Preparations: Solution, 0.25% (Betoptic S) and 0.5%.
Dosage: 1 drop once or twice daily.
Comment: Betaxolol’s relative β1 receptor selectivity reduces the risk of pulmonary side effects, but it is less effective at reducing intraocular pressure than the non-selective beta-blockers.
Sympathomimetic drugs, which reduce intraocular pressure by variable effects on production and drainage of aqueous, comprise the α2-adrenergic agonists apraclonidine and brimonidine, and dipivefrin, a pro-drug of the non-selective agonist epinephrine.
Apraclonidine hydrochloride is specifically indicated for prevention and management of intraocular pressure elevations after anterior segment laser procedures, and as adjunctive therapy in patients on maximally tolerated medical therapy who need further reduction of intraocular pressure. It lowers intraocular pressure by decreasing production of aqueous, the exact mechanism of which is not clearly understood, and may also improve aqueous outflow.
Preparation: Solution, 0.5% and 1%.
Dosage: 1 drop of 1% solution before anterior segment laser treatment and a second drop upon completion of the procedure. One drop of 0.5% solution 2 or 3 times a day as short-term adjunctive treatment in glaucoma uncontrolled by other medications.
Comment: Unlike clonidine, apraclonidine does not appear to penetrate blood–tissue barriers easily and produces few side effects. The reported systemic side effects include occasional decreases in diastolic blood pressure, bradycardia, and central nervous system symptoms of insomnia, irritability, and decreased libido. Ocular side effects include conjunctival blanching, upper lid elevation, mydriasis, and burning.
Brimonidine decreases aqueous production and perhaps also increases aqueous drainage through the uveoscleral pathway.
Preparation: Solution, 0.1 and 0.15%.
Dosage: 1 drop 2 or 3 times daily. May be used as monotherapy or in combination with other glaucoma medications. Frequently used as a replacement drug in patients unable to tolerate beta-blockers.
Toxicity: Brimonidine has only minimal effect on heart rate and blood pressure. Stinging on instillation, conjunctival hyperemia, and dry mouth are common side effects.
Dipivefrin is an esterified form, of epinephrine, which is a non-selective adrenergic agonist that primarily acts by increasing outflow of aqueous but also decreases aqueous production with long-term use. Dipivefin is thought to pass more quickly through the cornea than epinephrine and then is rapidly hydrolyzed to it.
Preparation: Solution, 0.1%.
Dosage: 1 drop twice daily.
Comment: Epinephrine is no longer available for treatment of glaucoma. When it first became available, its advantages over pilocarpine (see later in the chapter) were longer duration of action (12–72 hours) and no miosis, which was especially important in patients with cataracts. However, at least 25% of patients developed local allergies, others complained of headache and heart palpitation, and the outcome of glaucoma drainage surgery was found to be compromised. Local adverse effects are less frequent with dipiverfrin.
Inhibition of carbonic anhydrase in the secretory epithelium of the ciliary body reduces production of aqueous. The carbonic anhydrase inhibitors in use are sulfonamide derivatives.
Dorzolamide and brinzolamide can be used topically because they have sufficient corneal penetration to reach the ciliary body. They may be used as monotherapy but most frequently are used in combination with other glaucoma medications except for oral carbonic anhydrase inhibitors (see later in the chapter).
Toxicity: Local reactions include burning and stinging, superficial punctate keratopathy, and allergic reactions of the conjunctiva. Bitter after-taste is common. The systemic side effects associated with oral carbonic anhydrase agents are rare.
Preparation: Solution, 2%.
Dosage: 1 drop 3 times daily when used alone or twice daily if being used in combination with other topical glaucoma treatment.
Preparation: Suspension, 1%.
Dosage: 1 drop 3 times daily when used alone or twice daily if being used in combination with other topical glaucoma treatment.
All parasympathomimetics decrease intraocular pressure by increasing the outflow of aqueous through the trabecular meshwork.
Preparations: Solution, 0.25%, 0.5%–6%, 8%, and 10%; gel, 4%. Also available in a sustained-release system (Ocusert).
Dosage: 1 drop up to 6 times a day; a ½-in strip of gel in lower conjunctival cul-de-sac at bedtime.
Comment: Pilocarpine should be avoided in eyes with active uveitis.
Preparations: Solution, 0.75%, 1.5%, 2.25%, and 3%.
Dosage: 1 drop in each eye 3 or 4 times a day.
Comment: Carbachol is poorly absorbed through the cornea and usually is used if pilocarpine is ineffective. Its duration of action is 4–6 hours. If benzalkonium chloride is used as the vehicle, the penetration of carbachol is significantly increased. The pharmacodynamics of carbachol also include indirect activity.
Preparations: Solution, 0.25%, and ointment, 0.25%.
Dosage: 1 drop 3 or 4 times a day or ½-inch strip of ointment once or twice a day.
Comment: A high incidence of allergic reactions has limited the use of this old and seldom-used anti-glaucoma drug. It can be combined in the same solution with pilocarpine.
The following parasympathomimetics are strong and long-lasting and are used when other antiglaucoma medications fail to control the intraocular pressure. They are employed less frequently than in the past. The miosis produced is extreme; ciliary spasm and myopia are common. Local irritation is common, and phospholine iodide is believed to be cataractogenic in some patients. Pupillary block may occur. With the development of newer antiglaucoma medications, these agents rarely are used.
Preparations: Solution, 0.03%, 0.06%, 0.125%, and 0.25%.
Dosage: 1 drop once or twice daily or less often, depending on the response.
Comment: Echothiophate iodide is a long-acting drug similar to isoflurophate with the advantages of being water-soluble and causing less local irritation. Systemic toxicity may occur in the form of cholinergic stimulation, including salivation, nausea, vomiting, and diarrhea. Ocular side effects include cataract formation, spasm of accommodation, and iris cyst formation.
Preparations: Solution, 0.125% and 0.25%.
Dosage: 1 drop once or twice a day.
Comment: Systemic toxicity similar to that associated with echothiophate iodide may occur.
Increasing numbers of topical preparations combining pharmacologically different agents are being developed, mainly advocated to improve compliance but not necessarily resulting in as large a reduction in intraocular pressure as expected from summation of the effects of the individual agents administered separately. Most of them, except Cosopt, are not available in the United States. They include:
Azarga (brinzolamide 1% and timolol 0.5%), 1 drop twice daily.
Combigan (brimonidine 0.2% and timolol 0.5%), 1 drop twice daily.
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