Antiglaucoma medications: Nursing pharmacology

Anti-glaucoma medications are used to treat glaucoma, which refers to a group of eye conditions in which drainage of aqueous humor out of the eye is restricted, causing an increased intraocular pressure.

Now, anti-glaucoma medications can be divided based on their mechanism of action into two classes, those that decrease aqueous humor production and those that increase aqueous outflow.

Medications to decrease aqueous humor production include beta adrenergic blockers like Timolol, levobunolol, and betaxolol, and carbonic anhydrase inhibitors like brinzolamide and acetazolamide.

On the other hand, medications to improve aqueous outflow include prostaglandin analogs like latanoprost and bimatapoprost and cholinergic agents like pilocarpine.

Additionally, some medications can work by both decreasing the production and increasing the outflow of aqueous humor, including alpha adrenergic agonists like bramonidine and apriclonidine.

Finally, acute cases can be treated with osmotic diuretics like Menol. After administration, osmotic diuretics act as hyper-osmotic agents by creating an osmotic gradient that attracts water out of the eyes and into the blood to rapidly decrease intraocular pressure.

Almost all medications are administered as eye drops, with the exception of acetazolamide and mannitol, which can be administered orally and intravenously.

All right, now, the most common side effects of anti-glaucoma eye drops include blurred vision, eye redness, stinging, and itching following application.

In particular, beta adrenergic blockers cause neurological side effects like headache, depression, hallucination, and sleep problems like insomnia and nightmares.

Other side effects include hypotension, decreased cardiac output, and bradycardia, as well as bronchospasm leading to cough or dyspnea.

On the other hand, carbonic anhydrase inhibitors may cause neurologic side effects such as dizziness, drowsiness, and fatigue.

Carbonic anhydrase inhibitors can also cause gastrointestinal side effects such as nausea, vomiting, and diarrhea or constipation.

Now, acetazolamide in particular can also often cause electrolyte abnormalities, such as hypokalemia and hyperchloremia, as well as altered blood glucose levels, which can lead to hypo or hyperglycemia.

This can manifest as neurological side effects like headache, seizures, mental, Status changes and paresthesia. Finally, acetazolamide can cause serious side effects like hepatotoxicity and has a boxed warning for blood dyskrasias like pancytopenia, as well as for hypersensitivity reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis.

On the other hand, prostaglandin analogs are most often associated with side effects involving the eye itself, including darkening of the iris and eyelids, as well as eyelash growth.

Cholinergic agents can cause meiosis, increased lachrymation, and decreased night vision. Systemic side effects may include sweating, drooling, and gastrointestinal problems, among others.

Alpha adrenergic agonists may cause side effects like eye burning and tearing, photophobia and blurred vision. In addition, some clients may experience headache, dizziness, and somnolence, as well as dry nose or mouth, coughing and dyspnea.

Finally, the most common side effect of osmotic diuretics is frequent urination. In addition, these medications can also pull water from cells into the extracellular space, which could worsen edematous conditions like heart failure and pulmonary edema.

Water gets pulled into the blood vessels, the concentration of sodium will go down, causing dilutional hyponatremia. Other side effects include dehydration, hypotension, confusion, headache, nausea, and vomiting, which occurred due to the rapid fluid shift.

Now, anti-glaucoma medications should be used with caution during pregnancy and breastfeeding, while contraindications depend on the specific medication.

Beta adrenergic blockers and alpha adrenergic agonists should be avoided in clients with cardiovascular conditions like hypotension, severe bradycardia, 2nd or 3rd degree atrioventricular block, and decompensated heart failure.

In addition, beta blockers should be used with caution in clients with respiratory disorders such as asthma and chronic obstructive pulmonary disease or COPD, as well as in those with diabetes mellitus.

On the other hand, alpha adrenergic agonists should be used with caution in clients with cerebrovascular disease or Raynaud's phenomenon.

Next, carbonic anhydrase inhibitors are contraindicated in clients with severe renal or hepatic disease, severe renal or hepatic failure, sickle cell anemia, or Addison's disease, and should be used with caution in clients with COPD.

Finally, osmotic diuretics are contraindicated in clients with severe hypovolemia or dehydration, severe renal impairment and anuria, and should be used with caution in clients with edematous conditions such as heart failure and pulmonary edema.

All right. When caring for a client with glaucoma who is prescribed an anti-glaucoma medication, first ask them about their symptoms such as peripheral vision loss, severe eye pain, seeing colored halos around lights, or blurred vision, as well as headaches, nausea, and vomiting.

Then obtain their baseline vital signs and review your client's recent laboratory test results, including CBC, renal and hepatic function, and electrolytes.

Lastly, obtain their most current diagnostic test results, including visual acuity and intraocular pressure. Next, explain to your client how the anti-glaucoma medication will help reduce the pressure in their eyes, preventing loss of vision caused by glaucoma.

Then teach your client the correct technique for administering their eye drops. Instruct them to wash their hands with soap and water before and after using this medication.

If your client wears contact lenses, instruct them to remove them before using the medication, then wait 15 minutes afterwards to insert them again.

Also, if they are using other eye medications or an eye ointment, direct them to administer them at least 5 minutes apart.

Then if their anti-glaucoma medication is a gel forming solution, remind them to shake the bottle once before administering.

To administer the medication, advise them to either lie down or tilt the head back, pull down the lower eyelid with an index finger to form a pocket, hold the dropper with the other hand close to the eye but without actually touching the eye, and then instill the prescribed number of drops.

Afterwards, instruct them to close their eyes and place their index finger over the inner corner of the eye for about 1 minute to help prevent the medication from entering into the systemic circulation.

If they think that they didn't get the drop of medication into the eye properly, tell them to repeat the directions with a 2nd drop.

Then let your client know that most eye medications can cause transient side effects like stinging and burning eyes, blurred vision and photophobia, and prompt them to contact their healthcare provider if these side effects persist and do not resolve.

Emphasize the importance of taking their medication exactly as prescribed, and not to use more or less of it and not more often than prescribed.

Lastly, caution your client not to stop the medication abruptly and remind them to keep their regularly scheduled appointments to monitor their intraocular pressure.

Now, if your client is prescribed Timolol, instruct them to instill one drop in each affected eye as directed, either once daily or twice daily in the morning, depending on the solution.

Be sure to let them know that the medication can be absorbed systemically and cause side effects like cough, shortness of breath, low BP, and a slow heartbeat.

If these side effects occur, advise them to contact their healthcare provider. On the other hand, if your client is prescribed lateoprost, instruct them to instill one drop in each affected eye once daily in the evening.

Let them know that the medication can cause side effects like color changes of their irises, resulting in a heightened brown pigmentation, increased pigmentation of the eyelids, as well as increased length, thickness, and coloration of the eyelashes.

Also, the medication can cause their eyes to feel dry. If this side effect persists, advise your client to contact their healthcare provider for advice.

Finally, during treatment with an anti-glaucoma medication, monitor your client closely for the development of side effects, as well as for the resolution of symptoms like eye pain and vision problems, and for the therapeutic effect of decreased intraocular pressure.

All right, as a quick recap, anti-glaucoma medications are used to reduce intraocular pressure in clients with glaucoma.

These medications work by either decreasing aqueous humor production or increasing aqueous outflow. Their most common side effects include blurred vision, eye redness, stinging, and itching following application.

Nursing considerations are focused on performing a baseline assessment and monitoring for side effects and the therapeutic outcomes of the medication, as well as providing client education on safe self-administration, recognizing side effects that should be reported, and understanding the need for regular monitoring of their intraocular pressure.