BASICS OF OPHTHALMIC PHARMACOLOGY
Pharmacology is the term given to the study of the medicinal use and action of drugs. Also called medications, drugs plays an important role in most medical practices. In the ophthalmology office, medications are used chiefly to diagnose and treat diseases and to test for normal eye functions. As part of their duties, beginning ophthalmic medical assistants may call in the doctor's prescription for a specific medication to the pharmacy and may record drug information on the patient's history chart. As they become more familiar with medications used to treat eye disorders, assistants may administer certain kinds of drugs on instruction to the doctor. The experienced assistant, especially one who assists in surgical procedures, may need to set out certain types of medications for the doctor to use during certain procedures. To carry out these responsibilities, assistants should have a basic understanding of drug actions, patient reactions to these agents, and the general types and uses of pharmaceuticals in the ophthalmology practice. In addition, assistants must know how and when to administer medications. Any assistant who administer drugs should also be to recognize the symptoms of allergic reactions, as well as when such reactions require treatment and how to summon help.
Here, we describes the procedures for administering eye drops and oinments to patients. And also, we discusses the types, actions, functions of medications commonly used in the ophthalmology office, with an emphasis on their side effects and allergic reactions and, most important, the first aid procedures required for adverse drug reactions. Throughout, brand names of drugs are mentioned (in parentheless following the generic names) only for the purpose of familiarizing you with some of the names you will encounter.
DELIVERY SYSTEM OF DRUGS:
Patients receive ophthalmic drugs by three principal methods:
I. Topical, by which drugs are applied directly to the surface of the eye or surrounding skin.
II. Injectable, by which drugs are injected with a hypodermic needle into or around the eye or into another part of the body.
III. Oral, by which drugs are taken by mouth.
I.TOPICAL SYSTEMS:
Topical drugs include liquid drops in the form of solutions or suspensions, oinments, and special wafers called inserts for use on the surface of the eye or eyelids. Topical drug application is the most common type used in the ophthalmologist's office. These agents work well in a wide variety of tests and treatments involving the external and anterior eye structures. Ophthalmic medical assistants often apply topical drugs to patients undergoing eye tests.
1. SOLUTIONS:
A drug in solution is completely dissolved in an inert liquid called the vehicle, such as sterile salt water. Because the normal eye is hydrophobic (resists water), a topical solution may also contain a chemical to overcome this natural resistance. The solution may also include a preservative ingredient to prevent bacteria or other organisms from growing during storage. Occasionally, the preservative agent can irritate the eyes of some patients, causing redness, tearing or pain.
Solutions are used frequently in ophthalmologic practice because they are easy to apply as drops and do not interfere with vision, except, of course, for those drugs that alter vision as part of their desired action, such as medications used to dilate pupils. A prominent disadvantage of solutions is that the drops do not remain in contact with the surface of the eye for long; like tears, the medicinal drops drain through the lacrimal system into the nose and throat. Because solutions drain out of the eye, more frequent application may be required if they are used as a treatment. Solutions also may cause effects in other parts of the body.
2. SUSPENSIONS:
Suspensions are liquid vehicles in which particles of the drug are "suspended". Like solutions, suspensions may contain a preservative ingredient to inhibit the growth of bacteria and other unwanted organisms during storage. Suspensions are also easy to apply as drops and do not interfere with vision unless that is the desired action of the drug. Disadvantages of suspensions are that, like solutions, they do not remain in contact with the eye surface for long and that particles may settle out in the container during storage. If they active drug falls to the bottom of the bottle, it will not be delivered in an adequate amount unless the user shakes the container vigorously before each application. The ophthalmic medical assistant should check each container of medication before use in case it requires this procedure (some labels specify "Shake well before using")
3. OINTMENTS AND GELS:
In the form of an ointment or gel, the drug is dissolved or suspended in an oily or greasy vehicle. The chief advantage of an ointment or gel is that the drug remains in contact with the eye or lid longer than when in liquid solution or in liquid suspension. The greasy character makes the drug less likely to wash away with tears __a useful property in patients with excessive tearing or in crying children. However, ointments and gels may blur vision due to their inherent greasiness (although this effect can be rendered irrelevant by application at bedtime), and they can be difficult to apply correctly.
4. INSERTS:
Inserts are drug-containing wafer-like forms that are placed on the conjunctiva, usually under the upper or lower eyelid. Because of their matrix structure, inserts can release medication into the eye slowly. Some inserts can release medications up to a week before requiring replacement. Other inserts are soluble and dissolve over a period of several hours to a day. Soluble drugs inserts are a novel drug delivery system that is clinically available but is not in common use.
Advantages of drug inserts include infrequent application (because the wafer delivers a steady, even amount of drug) and a high degree of efficient drug use, coupled with a reduced chance of drug toxicity. Present disadvantages of this type of drug delivery system that it is expensive; may be difficult to insert, tolerate, or remove; and can become dislodged without the patient realizing it.
II. INJECTIONS:
With injections, the drug in solution is introduced into a part of the body by a needle. In ophthalmology, drug injections primarily serve as a means of applying treatment, but they can also be used in some testing or diagnostic procedures. Injections are usually given by a registered nurse or medical doctor.
Four types of injections are available in the practice of ophthalmology:
1. Into the eye (such as intravitreal) or around the eye (periocular, retrobulbar, or subconjunctival)
2. Into a vein (intravenous)
3. Into a muscle (intramuscular)
4. Under the skin (subcutaneous)
The intravenous, intramuscular and subcutaneous injections are classifed as systemic drug delivery because the active drug travels through the body's circulatory system before actually reaching the eye.
III. ORAL SYSTEMS:
Drugs taken orally (by mouth) include tablets, capsules and liquids. Oral drug intake belongs to the systemic drug delivery category because, as with certain types of injections, the active agent must travel through one or more other body systems before reaching the eye. The practice of ophthalmology uses few oral drugs. However, for patients with certain conditions, such as glaucoma, who cannot tolerate topical agents or whose disorder is not adequately controlled by them, oral drugs fill an important medical need.
OPHTHALMIC DRUGS - DIAGNOSTIC MEDICATIONS
OPHTHALMIC DRUGS - THERAPEUTIC MEDICATIONS
ADMINISTERING EYE DROPS AND OINTMENTS - INSTILLING DROPS/OINTMENTS
Pharmacology is the term given to the study of the medicinal use and action of drugs. Also called medications, drugs plays an important role in most medical practices. In the ophthalmology office, medications are used chiefly to diagnose and treat diseases and to test for normal eye functions. As part of their duties, beginning ophthalmic medical assistants may call in the doctor's prescription for a specific medication to the pharmacy and may record drug information on the patient's history chart. As they become more familiar with medications used to treat eye disorders, assistants may administer certain kinds of drugs on instruction to the doctor. The experienced assistant, especially one who assists in surgical procedures, may need to set out certain types of medications for the doctor to use during certain procedures. To carry out these responsibilities, assistants should have a basic understanding of drug actions, patient reactions to these agents, and the general types and uses of pharmaceuticals in the ophthalmology practice. In addition, assistants must know how and when to administer medications. Any assistant who administer drugs should also be to recognize the symptoms of allergic reactions, as well as when such reactions require treatment and how to summon help.
Here, we describes the procedures for administering eye drops and oinments to patients. And also, we discusses the types, actions, functions of medications commonly used in the ophthalmology office, with an emphasis on their side effects and allergic reactions and, most important, the first aid procedures required for adverse drug reactions. Throughout, brand names of drugs are mentioned (in parentheless following the generic names) only for the purpose of familiarizing you with some of the names you will encounter.
DELIVERY SYSTEM OF DRUGS:
Patients receive ophthalmic drugs by three principal methods:
I. Topical, by which drugs are applied directly to the surface of the eye or surrounding skin.
II. Injectable, by which drugs are injected with a hypodermic needle into or around the eye or into another part of the body.
III. Oral, by which drugs are taken by mouth.
I.TOPICAL SYSTEMS:
Topical drugs include liquid drops in the form of solutions or suspensions, oinments, and special wafers called inserts for use on the surface of the eye or eyelids. Topical drug application is the most common type used in the ophthalmologist's office. These agents work well in a wide variety of tests and treatments involving the external and anterior eye structures. Ophthalmic medical assistants often apply topical drugs to patients undergoing eye tests.
1. SOLUTIONS:
A drug in solution is completely dissolved in an inert liquid called the vehicle, such as sterile salt water. Because the normal eye is hydrophobic (resists water), a topical solution may also contain a chemical to overcome this natural resistance. The solution may also include a preservative ingredient to prevent bacteria or other organisms from growing during storage. Occasionally, the preservative agent can irritate the eyes of some patients, causing redness, tearing or pain.
Solutions are used frequently in ophthalmologic practice because they are easy to apply as drops and do not interfere with vision, except, of course, for those drugs that alter vision as part of their desired action, such as medications used to dilate pupils. A prominent disadvantage of solutions is that the drops do not remain in contact with the surface of the eye for long; like tears, the medicinal drops drain through the lacrimal system into the nose and throat. Because solutions drain out of the eye, more frequent application may be required if they are used as a treatment. Solutions also may cause effects in other parts of the body.
2. SUSPENSIONS:
Suspensions are liquid vehicles in which particles of the drug are "suspended". Like solutions, suspensions may contain a preservative ingredient to inhibit the growth of bacteria and other unwanted organisms during storage. Suspensions are also easy to apply as drops and do not interfere with vision unless that is the desired action of the drug. Disadvantages of suspensions are that, like solutions, they do not remain in contact with the eye surface for long and that particles may settle out in the container during storage. If they active drug falls to the bottom of the bottle, it will not be delivered in an adequate amount unless the user shakes the container vigorously before each application. The ophthalmic medical assistant should check each container of medication before use in case it requires this procedure (some labels specify "Shake well before using")
3. OINTMENTS AND GELS:
In the form of an ointment or gel, the drug is dissolved or suspended in an oily or greasy vehicle. The chief advantage of an ointment or gel is that the drug remains in contact with the eye or lid longer than when in liquid solution or in liquid suspension. The greasy character makes the drug less likely to wash away with tears __a useful property in patients with excessive tearing or in crying children. However, ointments and gels may blur vision due to their inherent greasiness (although this effect can be rendered irrelevant by application at bedtime), and they can be difficult to apply correctly.
4. INSERTS:
Inserts are drug-containing wafer-like forms that are placed on the conjunctiva, usually under the upper or lower eyelid. Because of their matrix structure, inserts can release medication into the eye slowly. Some inserts can release medications up to a week before requiring replacement. Other inserts are soluble and dissolve over a period of several hours to a day. Soluble drugs inserts are a novel drug delivery system that is clinically available but is not in common use.
Advantages of drug inserts include infrequent application (because the wafer delivers a steady, even amount of drug) and a high degree of efficient drug use, coupled with a reduced chance of drug toxicity. Present disadvantages of this type of drug delivery system that it is expensive; may be difficult to insert, tolerate, or remove; and can become dislodged without the patient realizing it.
II. INJECTIONS:
With injections, the drug in solution is introduced into a part of the body by a needle. In ophthalmology, drug injections primarily serve as a means of applying treatment, but they can also be used in some testing or diagnostic procedures. Injections are usually given by a registered nurse or medical doctor.
Four types of injections are available in the practice of ophthalmology:
1. Into the eye (such as intravitreal) or around the eye (periocular, retrobulbar, or subconjunctival)
2. Into a vein (intravenous)
3. Into a muscle (intramuscular)
4. Under the skin (subcutaneous)
The intravenous, intramuscular and subcutaneous injections are classifed as systemic drug delivery because the active drug travels through the body's circulatory system before actually reaching the eye.
III. ORAL SYSTEMS:
Drugs taken orally (by mouth) include tablets, capsules and liquids. Oral drug intake belongs to the systemic drug delivery category because, as with certain types of injections, the active agent must travel through one or more other body systems before reaching the eye. The practice of ophthalmology uses few oral drugs. However, for patients with certain conditions, such as glaucoma, who cannot tolerate topical agents or whose disorder is not adequately controlled by them, oral drugs fill an important medical need.
OPHTHALMIC DRUGS - DIAGNOSTIC MEDICATIONS
OPHTHALMIC DRUGS - THERAPEUTIC MEDICATIONS
ADMINISTERING EYE DROPS AND OINTMENTS - INSTILLING DROPS/OINTMENTS
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