POSTS
Pharmacology
Ocular Medicines (Instilling and Identifying)
Eye drops are used in ophthalmology to:
- Dilate the pupil
- Numbing the eye
- Treat Bacterial infections
- Treat allergies
- Treat viral infections
One disadvantage of eye drops is that they do not have long contact with the eye. If the eye requires prolong treatment then an ointment is prescribed. The problem with eye ointment is that it blurs the patients vision.
Instilling
Drops are instilled by:
Asking the patient to tilt his head back.
Asking the patient to look up. The patient may also look down to distribute the drop over the cornea, but this is uncommon.
Pulling down the lower lid.
Putting the drop in the inferior fornix of the eye.
It is good practices to recap ophthalmic drops. This prevents contamination. The main culprit for contaminating eye drops is Pseudomonas Aeruginosa. This bacteria is usually transferred from the eyelashes and loved to grow in the drops we instill. If you touch the eyelids with the tip of the dropper discard the bottle.
A topical ophthalmic drug is considered unsterile once it is opened. That does not mean that you can’t use it in the clinic. It is only when the drop is expired or has been _contaminated_ by microorganisms that the drop should be discarded.
Children have difficulty with drops. With children explain what is being done and do it quickly.
Identifying
Injected vs Topical vs Systemic
Sometimes injections are needed to treat patients with certain disorders. Injections have several advantages over topical medication. Injections can be provided at a specific site such as in the eye or in one of the muscles of the eye. Injections take effect immediately and can be delivered in higher concentrations.
One disadvantage of injections is that they are invasive.
Topical medication are drops placed directly on the eye. An example of a topical medication would be glaucoma drops. These drops are placed directly on the eye and function to open the trabecular meshwork (the drainage system of the eye). One advantage of topical eye drops is that many of them do not go systemic. Their actions mainly affect the eye.
Systemic Medication affect the whole body. They are taken either orally or by injection. If a patient presents with shingles that patient may receive a systemic oral medication. Conversely if a patient has a severe reaction epinephrine is a systemic injection.
Color Codes for Topical Ocular Medications |
|
Class | Color |
Anti-infectives | Tan |
Anti-inflammatories/steroids | Pink |
Mydriatics and cycloplegics | Red |
Nonsteroidal anti-inflammatories | Gray |
Miotics | Dark Green |
Beta-blockers | Yellow |
Beta-blocker combinations | Dark Blue |
Adrenergic agonists | Purple |
Carbonic anhydrase inhibitors | Orange |
Prostaglandin analogues | Turquoise |
The American Academy of Ophthalmology has approved the of color codes for the caps of topical medication.
Educate Patients on Medications
Anesthetics
After instillation of an anesthetic it is important to tell the patient no to rub their eyes. This is because patients can’t feel if they are rubbing their eyes to hard. They may damage their eyes. Also, anesthetic eyedrops are never prescribed for patients to take home. This sounds counterintuitive for patients who may have had a foreign body removed. Anesthetic drops cause corneal melting which will slow healing.
Dilation
Patients who undergo dilation and expect to have blurry vision. Near vision is affected more than distance vision.
Glaucoma Medication
Patients with glaucoma are given glaucoma drops. These drops unlike drops used to treat infection, are continued until the doctor decides to change treatment. Patients may be on a scheduled drop for glaucoma for the rest of their life. These drops usually do not improved vision, but slow down or stop the progression of glaucoma. It is important to stress the importance of being faithful to glaucoma drops to slow the onset of blindness.
Solution, Suspension, Emulsion
Which drops need to be shaken before each use?
The answer to this questions lies in the property of the drops. Suspensions and emulsions should be shaken. Solutions do not need to be shaken.
Some drops are solutions. This means that the solute is completely dissolved in the solvent. Proparacaine is an example of a solution.
Suspension drops are not one solution. If you had a cup of muddy water over time you will see that the particles will drop to the bottom. Pred Forte is a steroid suspension. We always tell patients to shake before they use it so that it is mixed well.
An emulsion is a solution in which the components do not blend. An example of this would be vinaigrette dressing. Durezol is an emulsion. Just like you shake vinaigrette before you use it you also want to ask patients to shake an emulsion drop before they use it.
Drug Reactions
Allergies
There may come a time when patients receive a medication that they are allergic to. You can tell that a patient is having an allergic reaction because they may have the following symptoms:
- itching
- redness
- swelling
Sometimes this can be so bad that it looks like the patient got hit in the face. An allergic reaction this bad is nicknamed “allergic shiner”.
Irrigation
When a harmful substance enters the eye the first thing that the provider must do is irrigate the eye.
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