Pharmacology

General pharmacology

Pharmacology is the study of the action and uses of medicinal drugs. To properly assist a doctor, it is essential for the beginning ophthalmic assistant to know about the basic principles of using different medication, whether it is a systemic medication or an ocular medication. They should be able to administer the drug in the proper dosage and through proper route. They should be able to identify the adverse effects of commonly used drugs and should summon help in such an occasion. This particular section deals with the various drugs used for diagnosing and treating diseases, their effects and side effects. It also gives the precautions the ophthalmic assistants should keep in mind while administering the drugs. Only when the assistants have an overview of these aspects of medications can they appropriately assist the ophthalmologist and be of great help in day to day practice.

Definition - Pharmacology

The study of drugs is called pharmacology. The drugs are prepared naturally from plants, from animals and from minerals. Some medicines are prepared as gases e.g., oxygen, carbon dioxide, nitrous oxide. Some drugs are prepared artificially from other sources (synthetic drugs).

Trade Name

This is the name given by the manufacturer.

Chemical Name/Generic Name

The name of the chemicals constituting the medicine.

Uses of drugs

• To treat a disease - (therapeutic drugs)
• To prevent a disease - (prophylactic drug)
• To diagnose a disease - (diagnostic agents)
• To alleviate the signs and symptoms of a disease - (e.g., analgesics)

Types of medicines

Antibiotics

Antibiotics prevent the growth of microorganisms and cure infections. There are many types of antibiotics. After identifying the organism causing the disease, the doctor prescribes appropriate antibiotics. Precautions to be followed before starting the drug.

1. Always ask the patients if they have any allergy to any specific drug. Most commonly allergic reactions are seen for penicillin (e.g., penicillin injection, ampicillin) and sulpha e.g., (Cotrimoxazole) Test dose should be given before starting any parentral (intramuscular or intravenous) injections of such drugs.
2. Patient should report immediately if they develop blisters on their body or oral cavity or conjunctiva which may be the first sign of allergy to drug (called Stevens Johnson syndrome). The patient should be vigilant to look for these signs.
3. If starting the patient on any oral treatment, they must be correctly instructed to report immediately if they develop rash / itching or any systemic complaints immediately after starting the drug.
4. Patient should be instructed to take the antibiotic in the scheduled dose for the scheduled time which is important to avoid emergence of bacterial resistance to the antibiotic (i.e., that particular bacteria does not respond to that antibiotic during a subsequent infection).

Analgesic

Analgesics are painkillers. There are two types of analgesics

• Corticosteroids (potent drugs)
• Non steroidal anti inflammatory drugs (NSAID) (less potent drugs)

Analgesic can be given with or without sleeping doses

Non steroidal anti Inflammatory drugs NSAIDS

E.g. aspirin, paracetamol, ibuprofen (brufen). Precautions to be followed before starting the drug

• Ask for drug allergy
• H/O acid peptic diseases
• Advise patients to take the drug after food
• Patient with acid peptic disease - avoid aspirin, ibuprofen. Milder drugs like paracetamol can be used with care
• Report any allergic manifestations

Corticosteroids

Precautions to be followed before starting the drug

• These are drugs started with caution; the patients have to be monitored continuously
• If given continuously it may cause side effects which have to be checked, ex: weight gain, hypertension, thinning of long bones (can fracture with trivial trauma), depression etc.
• Steroids must not be stopped abruptly. They have to be tapered and stopped under a doctors' guidance
• If stopped abruptly patients may present with a variety of systemic problems due to the dependency on the steroids administered We have to rule out infections like tuberculosis (with chest x-ray and sputum examination) and diabetes, which may be aggravated by steroid treatment.

Anti hypertensives

Anti hypertensives control hypertension. When the blood pressure is high, anti hypertensives are given. Nifedipine is an example.

Precautions to be followed before starting the drug

• Rule out history of asthma: atenolol and similar drugs (beta blockers) to be avoided
• Kidney diseases: If both kidneys are involved avoid enalapril
• Some drugs may cause sudden drop of blood pressure and cause giddiness / fainting attacks. Hence, start at low dose and gradually increase. Always monitor the patient for end organ diseases, involvement of kidney, eye, heart and brain.

Gastro-intestinal medicines

Diseases of the stomach and intestine are controlled by medicines.
a. Ulcer - Antacids e.g., digene, gelucil
b. Diarrhoea - Antibiotics, anti diarrhoeals and oral rehydration solutions
Diarrhoea: Anti diarrhoeal drugs are better avoided because they may cause further problems if diarrhoea is of an infective cause. Patient should be instructed about how to prepare and take oral rehydration solution (ORS).
c. Constipation- Bulk forming drugs like isphagula

Oral hypoglycemic agents

These medicines reduce the blood sugar level. These are drugs given in diabetes mellitus. The commonly used drugs are:
- Glyciphage
- Daonil

Insulin

Injectable hypoglycemic agent. Insulin is of three types. They react:

a. Immediately and - Short acting e.g., short durations Regular insulin (Human actrapid/H4)

b. At a moderate rate - Intermediate actions e.g., NPH, Linte (Human monotaed)

c. Slowly - Long acting e.g., (Ultra lenti)

d. Premixed insulin - Short acting + inter mediate acting e.g.,(Mixtard)

Insulin

Acute infections and other situations may require change to insulin

• Insulin should be taken half (½) an hour before food
• Avoid skipping meals
• Report if any allergy develops
• Immunosuppressives

Oral hypoglycemic drugs

• Should be given before food
• Diet should be on proper time and proper quantity as instructed by the physician
• Avoid skipping meals
• Instruct the patient about hypoglycemia and its symptoms which may develop if they skip meals. e.g. sweating, giddiness
• Advise the patient to keep some sweets with him/her which will be useful in situations of hypoglycemia

Routes of drug administration

Oral - Tablet and syrup

Local applications - Topical drops, ointments

Injections

Systemic

• Intra muscular (I.M)
• Intra venous (I.V)
• Subcutaneous

In eye

• Intravitreal
• Retrobulbar, peribulbar
• Sub - conjunctival
• Sub - tenon's
• Intracameral

The forms of medicines

Drugs are available in solid, liquid, powder and gaseous forms. Drugs are stored in bottles, boxes and the gases in cylinders.

The Law for keeping and selling drugs

• The drugs can be issued to a patient only on issue of prescription
• The drugs that can induce habit formation should be kept under lock and key
• No drugs should be prescribed to a client without the order of the doctor
• The prescription should be written and signed by a doctor only

Drug safety

• Drugs should be checked and kept secure
• The names should be written legibly
• They should be covered tightly
• If the colour has changed or if the expiry date is over it should not be used. The drugs which need to be clear should not have any turbidity
• The drugs needs to be stored at appropriate temperature
• The drugs should be kept away from the reach of children
• The dangerous drugs should be kept under lock and key

Common Drugs and Examples

Types of drugs	Examples of drugs	Usage
Analgesics and antipyretics	Paracetamol	Fever and headache
Anaesthetic agents	Ether, Nitrous oxide, Lignocaine	Produces general and local anesthesia
Anti hypertensives	Nifedipine, Diltiazem	Reduces blood pressure
Anti Ulcer drugs	Gelucil, Digene Ranitidine,Omeprazole	Used to treat gastritis and ulcer
Hypoglycemic agents	Daonil, Glyciphage, Insulin	Used in diabetic patients to reduce blood glucose levels
Bronchodilators	Deriphylline, Salbutmol, Aminophylline	Used in asthma patients to reduce wheezing
Antihistamines	Avil, cetrizine	Used in cold, allergic reactions to drugs or any other allergy
Antibiotics	Penicillin, ampicillin	Used to treat bacterial infections
Anti helmenthics	Nemocid, mebendazole	Used to treat worm infestation
Cardiac drugs	Digoxin, sorbitrate, monotrate	Used in myocardial infarction and ischemic heart disease
Anti fungal agents	Nystatin, Whitfield's ointment,Gentian violet, Amphotericin	Used to treat infection caused by fungi
Narcotic sedatives	Fortwin, Morphine, Pethidine,Narcotic analgesics	Used in severe pain (post-operative), to induce sleep and in pulmonary edema
Antidotes	Atropine	Used in insecticide poisoning
Psychiatric medicines	Largactil, reserpine	Used in patients with psychiatric disorders
Anti anxiety drugs	Alprazolam, Diazepam	Used in convulsions and in patients with anxiety disorder.
Corticosteroids	Dexamethasone, Hydrocortisone	Used in inflammatory disorders
Diuretics	Lasix, furosemide	Used in pulmonary edema and renal failure
Emergency drugs	Adrenaline Atropine Sodium bicarbonate Dopamine Calcium Gluconate Oxygen Sorbitrate	Used in cardio pulmonary arrest To stimulate heart function Acidosis Hypo tension Used in cardio pulmonary arrest Cardiac and respiratory diseases Chest pain in myocardial infarction

Rules for administering medications

• You should know the reasons for administering that particular medicine and the measurement.
• Administer the medicine correctly by following the doctor's orders
• The five rights to be followed while administering medications
  • Right drug
  • Right time
  • Right dosage
  • Right patient*
  • Right route

  (*The right patient involves positively identifying the patient. Special care must be taken when there are two / more people with the same name, in the same room or unit.)

• Check the label of the drug / eye drops before administering
• Always check the expiry date
• Do not use any medicines if it is not labeled
• Do not use if there is any damage in the bottle / if the nozzle cap is lost
• Follow the instructions carefully to mix medicine
• The drugs should be given to the patient and not to anyone else
• Do not use if the color has changed / if there is any turbidity in an eye drop / IV Solution
• If the patient refuses to have eye drops instilled or use a drug, or it is omitted for any reason it should be recorded in the patient 's case sheet along with the reason
• Record the date, time, route of medicine- only after instilling the drops / after the patient swallows the tablet or syrup / or after giving an injection
• You should be aware of the drug's side effects before administering the medicine
• It is possible for errors to happen. As soon as it is realized, check the patient's eye and immediately notify the doctor

Giving drugs to children

1. The quantity of the medicine must be carefully measured
2. Medicines in liquid form must have a syrup base, or it must be mixed with honey or sugar
3. Tablets must be powdered to enable the child to swallow easily. Do not mix the drugs in milk or food; the child may start avoiding food itself
4. Keep the child in sitting position while administering the drug. If the child takes the drug happily, appreciate it. Don't force the medicine down the throat. It is better if the child sips it. Encourage the child to drink it on his own; or encourage the child to keep his fingers on the spoon
5. Inform the doctor when a child refuses to take a particular medicine or vomits

Expansion of abbreviations

QD - Once in a Day

BD - Twice a Day

Tid / Tds - Thrice a Day

Qid - Four times a day

Sos - Whenever Necessary

Stat - Immediately

Q6H - Every Six Hour

A.C - Anti Cebum (before meals)

P.C. - Post Cebum (after meals)

P.O - Per Oral

H.S. - At bed time

IV - Intra venous

IM - Intramuscularly

S.C - Subcutaneous

One hourly - 12 Times a day (Every 1 hour)

Two hourly - 6 Times a day (Every 2 hour)

Fourth hourly - 3 Times a day

Six hourly - 2 Times a day

G - Drops

OC - Ointments

↑↑ - High (increase)

↓↓ - Low (decrease)

One Teaspoon - 5 ML

One Table Spoon - 15 ML

One Ounce - 30 ML

One Pound - 450 ML

One Pint - 600 ML

Ocular pharmacology

What are eye drops?

Ophthalmic medical assistants commonly assist the ophthalmologist by instilling eye drops in patients' eyes. Eye drops are drugs in liquid form that are applied to the surface of the eye (topically). Diagnostic types of eye drops are used during certain eye tests; therapeutic eye drops are used to treat ocular conditions or diseases.

Forms of ocular medicines

Ocular medications are formulated in three forms as solutions, suspension and ointments.

Solutions

These are in liquid forms and usually they are instilled into the eye. In a solution, the active drug is completely dissolved in an inactive, transparent liquid.

Suspensions

In a suspension, particles of the drug are visibly suspended in a liquid. The fluid is cloudy or milky, unlike a solution, which is clear. Shake the suspension well before use.

Ointment

Ointment contains a drug added to an oil base. The ointment melts on the warm skin and is absorbed into the tissues.

Classification, uses, action and adverse effects

Drugs for use in the eye are classified according to their action as follows:

• Mydriatics and cycloplegics
• Miotics
• Antibiotics
• Anti-inflammatory drugs
• Anti-viral drugs
• Local anaesthetics
• Tear substitutes
• Diagnostic stains
• Immunosuppressives

Mydriatics and cycloplegics

Mydriatics drugs dilate the pupil by affecting the dilatory and contracting muscles of the iris; cycloplegics paralyse the ciliary muscles to prevent the process of accommodation of the lens.

Uses of mydriatics

• Examination of the fundus
• The treatment of inflammatory eye disease like iridocyclitis. The effect of the drug is to relax the smooth muscles of the iris and ciliary body, thereby resting the eye
• Preoperative dilatation of the pupil
• Refraction
• Postoperatively to prevent formation of synechiae (adhesions)

The commonly used mydriatics

• Atropine Sulphate
• Homatropine
• Tropicamide
• Cyclopentolate
• Phenylephrine

Atropine 1%

This is both a mydriatic and cycloplegic drug. Its effect may last for up to 10 days following instillation. Excessive use of atropine can cause systemic side effects - drying of the mouth and tachycardia by absorption through the conjunctiva.

Homatropine 2- 5%

This is a derivative of atropine with a weaker and shorter action, wearing off after two days.

Cyclopentolate (Mydrilate 0.5 - 1%)

This drug is a mydriatic and cycloplegic. It dilates with 15 minutes and wears off by 8 hours; it is therefore often used for examination in the clinic.

Tropicamide (0.5 - 1%)

This is effective within 15 minutes and wears off in 6 hours.

Phenylephrine (Drosyn 2.5, 5 and 10%)

This drug is a mydriatic only. It does not cause cycloplegia. It dilates within 15 minutes and wears off in a few hours.

Instilling dilating drops

Basic policies to be followed prior to using mydriatics and cycloplegics

• Check for shallow AC with torchlight and inform doctor if angle is shallow - get permission to dilate
• Patient should be told the nature of the drug and its action and of blurred vision
• Confirm that the patient has not come driving any vehicle or he has somebody along with him
• Explain that they cannot read for the specified duration of action of that drug
• Rule out any previous H/O allergy to the drug
• Do not use combination of phenyl epheneprine for cardiac and hypertensives as it may cause increase in blood pressure by absorption through conjunctiva

Miotics - (Constrictors)

Miotics causes contraction of the iris sphincter muscles, resulting in constriction of pupil size and decreases the elevated IOP by opening up the angle of the anterior chamber. This helps to relieve angle closure glaucoma. By increasing the flow of aqueous through the trabecular mesh work it lowers the intra ocular pressure in open angle glaucoma.

Uses of miotics

• Used in primary open angle glaucoma.
• For emergency relief of angle closure glaucoma to control IOP
• Chronic open angle glaucoma
• Ocular hypertension

Commonly used miotics

• Pilocarpine 1%- 4%
• Pilocarpine Hydrochloride
• Pilocarpine Nitrate

Pilocarpine

Used in primary open angle glaucoma. The effect of pilocarpine lasts for about 8 hours. It is also used to reverse the actions of a mydriatic after a clinical examination.

The patient should be told about transient stinging and burning on installation. Also the patient may experience watering, congestion, peri-or supra-orbital headache.

Pilocarpine should not be used in patients with asthma / hypertension.

Pilocarpine Nitrate 1%, 2%, 4% (Carporen, Pilocar, Pilagan) cause.

a) Miosis
b) Increase in accommodation
c) Decrease IOP due to increase outflow
Onset: 1 hour.
Effect: 6 Hours
Uses: All POAG, PACG, before ALT NAD Laser PI procedure

Side effect of pilocarpine

• Blurring vision, head ache, cataract, iris cyst,
• Lacrimation, (due to irritation and punctal occlusion)

Contraindication

Retinal detachment, high myopia

Anti Glaucoma drugs

In addition to miotics, there are other drugs that reduce intraocular pressure in glaucoma. These are

• Beta-blockers
• Osmotic agents

Beta-Blockers

These drugs lower the intraocular pressure by decreasing the production of aqueous fluid and by increasing the outflow of the aqueous humor.

• Ask for history of asthma
• Beta blockers should not be given in asthma
• Should be avoided in cardiac patient as cardiac failure can be precipitated

Commonly used beta-blockers

• Timolol 0.25 - 0.5%
• Betaxolol 0.5%
• Levobunalol

They can be used twice daily and have very few side effects in the eye. However, they may cause the following adverse effects

• Ocular irritation including conjunctivitis, keratitis, blepharitis
• Decreased corneal sensitivity in long term use
• Asthmatic attacks in patients with history of asthma
• Visual disturbances including refractive changes

Diamox (acetazolamide)

This drug inhibits an enzyme called carbonic anhydrase which acts in the production of aqueous fluid. It reduces the production of aqueous from the ciliary body, thus lowering the intraocular pressure.

Diamox is usually taken as 250 mg tablets once every 6 hours. It is also available as a slow release capsule of 500 mg. The following side effects may be experienced.

• Transient myopia
• Perioral numbness
• Electrolyte imbalance
• Gastrointestinal discomfort
• Prolonged use may cause kidney stones.
• It can cause hypokalemia (instruct patient to take fruits)

Osmotic agents

They absorb fluid from ocular tissue and lower the intraocular pressure. They used to treat acute angle closure glaucoma. The common side effects are nausea, vomiting, increased urine output and heart failure.

The commonly used osmotic agents

• Oral glycerol
• Inj.mannitol

Glycerol

This is a liquid given orally. Usually a dose of 1 to 1.5 ml per kilogram of body weight is given. It may be mixed with fruit juice to make it taste better.

Mannitol 5 - 20%

A dose of 2 gram per kilogram of body weight is given by rapid intravenous infusion. Check blood pressure before administering as it may cause further BP fall.

Mechanism	: Water transfer from the eye to blood
Dose	: (1mg/1kg) per kg body weight max 60 drops per minute (IV).
Action	: 30 Minutes
Effect	: 6 hours
Contraindication	: Cardiac patient (pulmonary edema) more urine produ-ction. After mannitol, patient should be still for 4 hrs (intra cranial pressure will reduce) Herniation of brain stem in erect position. So heart lungs function will get reduced

Antibiotics

Antibiotics are used to prevent and treat bacterial infections of the eye.

Uses of antibiotics

• Prophylactically given after cataract surgery to prevent infection
• Conjunctival and corneal infections - topical antibiotics
• Infections caused by penetrating injuries and bacterial corneal ulcers
• Subconjunctival antibiotic injections
• For infections inside the eye (endophthalmitis) very small amounts of certain antibiotics may be injected directly into the vitreous body by the doctor

Commonly used antibiotics

1. Chloramphenicol 0.5%: Vanmycetin, Chlormet, Dexoren, Chlorocol
2. Gentamycin 0.3%: Genticyn, Garamycin, Bactigen, Genoptic
3. Ciprofloxacin 0.3%: Ciplox, Quinobact, Ocuflox, Milflox, Ciprozen, Ciprolen
4. Norfloxacin 0.3% : Norflox, Floxiren, Norzen
5. Ofloxacin 0.3% :Exocin, Ocucin, Ofloren, Oflacin, Zo
6. Tobramycin 0.3% Toba; Tobaren; Eyebrex

Penicillin Group of antibiotics

Benzyl penicillin - used in ophthalmia neonaturum

Aminoglycocides

• Gentamicin
• Tobramycin
• Amikacin
• Fortified Gentamicin (Supergara - Inj. Gentamicin 80mg is added to gentamicin eye drops)
• Neomycin
• Spiramycin

Broad spectrum antibiotics

• Ofloxacin

Fluoroquinolones

• Ciprofloxacin
• Ofloxacin
• Gatefloxacin
• Sparfloxacin
• Lomefloxacin

Cephalosporins

• Cefazolin

Sulphonamides

• Sulphacetamide (Locula)

Antibiotic drops and ointments can cause local burning, discomfort, itching, conjunctival hyperemia and impairment of taste.

Anti - viral drugs

These act by inhibiting the growth of viruses. These drugs are used in the treatment of herpetic corneal ulcers (dendritic ulcers).

Commonly used antiviral drugs

• Idox uridine (I.D.U.) - available in drop and ointment form
• Acyclovir is available as eye ointment .It can also be given systemically

Anti - fungal drugs

These drugs are used in the treatment of fungal corneal ulcers and fungal keratitis.

• Natamycin
• Fluconazole
• Nystatin
• Amphotericin B

The Adverse effects

• Burning, pruiritis, stinging,
• Erythema
• Headache, nervousness, nausea, vomiting

Anti - inflammatory drugs

There are two types of anti inflammatory drugs

1. Corticosteroids : The most powerful anti-inflammatory drugs are the corticosteroids. They can be combined with antibiotics. Chloramphenicol with Dexamethasone, Prednisolone acetate, Prednisolone sodium phosphate, Prednisolone and betamethasone, Fluromethalone, Betnesol N, tobramycin with dexamethasone.

2. Non steroidal anti inflammatory drugs : These are less powerful than corticosteroids. Examples

• Diclofenac sodium (Voveran ophtha eye drops)
• Ketoralac (Ketlur eye drops)
• Flurbiprofen (Flur eye Drops)

Uses of anti inflammatory drugs

• Local and systemic treatment of uveitis
• Scleritis
• Allergic types of conjunctivitis and keratitis.

Most of the anti-inflammatory drugs are steroids. Prolonged use of steroids may result in increased intra ocular pressure, corneal ulceration, cataract.

Local anaesthetics

Local anesthetics drops are used to anaesthetise the cornea or conjunctiva.

Uses of local anesthetics

Used in short corneal and conjunctival procedures such as.

• Tonometry
• Lacrimal duct patency
• Gonioscopy
• Removal of foreign bodies
• Suture removal
• Corneal & conjunctival scrapings for diagnostic purposes
• Paracentesis of anterior chamber

The commonly used local anaesthetics include

• Lignocaine HCl
• Proparacaine HCl

Allergic reaction in some patients is noted. Initial irritation, stinging, burning may occur after instillation.

Tear substitutes / artificial tears

Tear substitutes are viscous substances that help to maintain a thin film of fluid over the corneal surface.

Uses of tear substitute

• Used in lacrimal secretion deficiency, dry eye syndrome
• Used to treat burning, irritation, and dryness of the eye
• Soothing, lubricating and moisturizing of corneal tissues
• Bonding Gonioscopic prisms to the eye (Viscosity around 40 cps)
• Used in corneal staining

Artificial tears drops

1. Polyvinyl Alcohol + Povidone - Tears Plus, Dudrop, I-Lube, Irisol plus
2. Hydroxypropyl methyl cellulose - Moisol
3. Carboxymethyl cellulose sodium 0.5% - Refresh tears

Diagnostic stains

Corneal damages either from an ulcer or following trauma may be demonstrated by the use of stains.

The most common stains are

Fluorescein 2% - Stains live tissue

Rose Bengal 1% - Stains dead tissue

Uses of fluorescein

• For evaluating contact lens fitting, whether it is ideal, loose or tight
• Help in preliminary diagnosis of corneal ulcer and conjunctival problems(stippling, abrasions, ulcerations, foreign bodies etc.)
• Applanation tonometry
• Ophthalmic angiography - IV Fluorescein is used
• Advocated for visualization of choroidal vessels with infrared absorption - ICG

Fluorescein when diluted shows up green and using light from a cobalt-blue filter intensifies the fluorescent effect.

Fluorescein is excreted in breast milk. Use caution when administering to a nursing woman. Urticarial reactions have also occurred in patients without history of allergy to iodides. Also while applying fluorescein drops to the eye, be cautious not to spill the dye, which will stain clothing.

Uses of rose Bengal 1%

Rose Bengal stains diseased cells as in herpes simplex keratitis, corneal ulceration and dry eye syndrome.

Immunosuppressive drugs

These are drugs used for lowering the immune status of the body. In certain diseases the immune mechanism of the body increases the inflammation and affects the vision. Medications developed to suppress the body's normal production of antibodies that fight foreign substances such as transplants, bacteria and infections are known as immunosuppressive. In order to keep the inflammation under control, immunosuppressive drugs are given. It is also given in malignancies. Examples of immunosuppressive: Cyclophos-pharmide, Azathioprine, Methotrexate, Cyclo-sporine).

Side effects of commonly used immunosuppressive drugs

• Nausea and vomiting - It is quite common
• Bone marrow depression - Recognised by reduced RBC and WBC count in blood. Hence the importance of periodically testing blood counts
• Liver toxicity - Jaundice may be seen. investigations like SGOT, SCPT, platelet count need to be done
• Renal toxicity - decreased imbalances for investigation
• Hair loss - needs reassurance
• Infections - Due to reduced immunity of the body
• Pregnant women - causes fetal malformations
• Malignancies - can also develop (different from the one being treated)
• Sterility - inability to conceive

These points should be kept in mind while dealing with a patient on immunosuppressives. The treating doctor should be appropriately informed on noticing these side effects. The OA can create awareness about these complications so that the patient and relatives are not alarmed.

Patients on immunosuppressive drugs should follow certain precautions

• They should come for regular follow up visits as advised by the doctor
• They should not change the dose or stop the drug on their own and should not restart the drug on their own
• If they develop side effects listed above they should contact the doctor immediately
• They should avoid contact with people having infections to prevent acquiring infections

Summary

Pharmacology, both general and ocular, is explained in simple language to aid OA to monitor and administer commonly used drugs with a scientific basis and help them to recognize the common problems encountered in the day to day medical practice. In this way they are a great help for the ophthalmologist. Some of the drugs might give allergic reaction. Therefore, the OA should clarify with the patient whether the patient is allergic to any drug. The OA should inform the patient about certain anesthetic drugs that might cause a glare. The effect of the drugs must be known so the patient need not be agitated while they come across any mild symptoms. In case of high risk patient they should be very careful in administering drugs that could bring down BP, cause depressions, dizziness, nausea or any other side effects. The OA should verify the patient case sheets before administering the drugs.

Classification	Action	Uses	Side Effect	Contra Indication
Mydriatics&cycloplegics - Atropine - Homatropine - Cycloentolate - Tropicamide - Phenyl ephrine	Dilate the pupil	- Fundus exam - Refraction - Treatment of iridocyclitis	- Irritability - Ocular congestion - Photophobia	- Shallow anterior chamber
Miotics / Pilocarpine	Contrict the Pupil Hypertension	Glaucoma	- Watering - Congestion - Supra Orbital Headache	-Asthma - Hypertension
Other Drugs used in Glaucoma Beta Blockers	Decrease the production of Aqueous	Glaucoma	Ocular Irritation	-Asthma - Hypertension
Diamox	Decrease the production of aqueous	Glaucoma	Transient myopia, Kidney Stones	Kidney Stones
Osmotic agents Glycerol & Mannitol	Absorb the fluid from Ocular Tissue	Acute Glaucoma	Cardiac failure and electrolite imbalance	- Cardiac patients
Antibiotics & Antivirals	Destroys the bacteria or virus causing infection	Prevents and treat the infection	Local burning impairement of taste and conjunctival hyeremia	Avoid in patient with history of hypersensitive reaction
Anti inflammatory	Destroys the inflammatory reaction by decreasing the infiltration of WBCs at the site of inflammation	Used seperately /in combination with antibiotics to prevent and treat any ocular inflammatory condition	Increase intra ocular pressure Corneal ulceration Glaucoma and cataract with excessive long term use

Key points to remember

• Drugs are used to treat a disease, to prevent a disease, to diagnose a disease and to alleviate the signs and symptoms of a disease
• The common systemic drugs related to the field of ophthalmology are antibiotics, analgesic, anti hypertensives, gastrointestinal drugs and oral hypoglycemic agents
• The prescription should be given by a doctor only
• It is important to keep the drugs safely, the dangerous drugs under lock and key
• Follow the rules while administering any drug
• Follow the five rights:
  Right drug, Right time, Right dosage, Right patient and the Right route
• Ocular medicines are available in the form of drops, suspensions and ointment

Common drug names

Steroids

• Dexamethasone - Decadran
• Betamethasone - Betnesol
• Hydrocortisone - Wycort
• Predinisolone - Predforte / Predmet
• Loteprednol - Lotepred 0.5%

Antibiotics with steroids

• Betnesol-N - Betamethasone with Neomycin
• Chloromet-DM - Chloramphenicol with Dexamethasone
• Genticyn-B - Gentamycin with Betamethasone
• Toba-DM - Tobramycin with Dexamethasone.
• Sofracort - Soframycin with cortisone
• Dexoren-S - Chloramphenicol with dexamethasone

Anti Bacterial

• Ciprofloxacin 0.3%
• Cefazoline drops
• Ofloxacin 0.3%

Gram Positive Ulcer	Gram Negative Ulcer
Ciplox	Gentamycin
Cefazoline	Tobramycin
Chloramphenicol Vancomycin

Anti viral

• Ridinox eye drops
• Acyclovir 3% oint (Acivir oint / Ocuvir oint / Herperax oint)
• Ocuvir Applicaps
• Vira - A Ointment

Anti fungal

• Natamycin 5% (Natamet, Elmycin)
• Ketaconazole 2%
• Fluconazole
• Itraconazole 1% (Itral drops and Oint)
• Nystin Ointment

Dilators - (Mydriatic + Cycloplegic)

- Mydriatic	- Dilatation only
- Cycloplegic	- Ciliary Muscle Paralysis

Pupil size

Normal - 3 to 5mm

Mydriasis - More than 5mm

Miosis - Less than 3mm

Mydriatic

• Phenylephrine 5%, 10% (Drosyn)
• Tropicamide Plus,
• Tropicamide 1%

Cycloplegic

• Cyclopentolate 1%
• Atropine 1%
• Homatropine 2%

Uses

1. Corneal ulcer
2. Iritis

Action of cycloplegics

1. Gives rest to ciliary body (cycloplegic effect)
2. Relieves pain
3. Relieves photophobia
4. Increases blood supply
5. Local anaesthetic effect

Phenylephrine 5%, 10% (Drosyn)

Mydriatic only. On set	- 30 minutes (Action)
Duration	- 4 hours (Effect)

Tropicamide Plus (Tropicamide with phenylephrine)

Fast acting Mydriatic on set	- 15 minutes
Duration	- 2 hours
Used in Refraction, Fundus examination

Cyclopentolate - Cyclogic 1%

Mydriatic + Cycloplegic. on set	- 20 - 45 minutes
Duration	- 12 - 24 hours

Homatropine 1% - Mydriatic + cycloplegic

Onset: 30-45mts
Effect: 12-36hrs

Atropine - Atropine Sulphate 1%

Mydriatic + Cycloplegic
Duration of action 15 days

The commonly used beta blockers are Timolol, Betaxalol and Levobunalol. Ask for drug allergy before starting a drug.

Student exercise

A. Fill in the blanks

1. The drugs that dilate the pupil are_________ and ___________.
2. The drugs that constrict a pupil are ________.
3. __________ is an example of beta blockers.
4. The other name of Diamox is ______________.
5. The commonly used osmotic agents are __________ and___________.

B. Choose the most appropriate answer

1. Which of the following drugs is not an antibiotic?

a) Chloramphenicol	b) Ciprofloxacin
c) Diamox	d) Tobramycin

2. Which of the following is an antiviral drug?

a) Acyclovir	b) Atropine
c) Betaxolol	d) Neomycin

3. The drug that is used in asthma patients

a) Salbutamol	b) Avil
c) Digoxin	d) Ranitidine

4. An anti fungal drug

a) Fortwin	b) Omez
c) Nemocid	d) Amphotericin

5. Dexamethasone is __________.

a) Antibiotic	b) Corticosteroid
c) Anti allergic	d) Cardiac drug

C. Match the following

1. Blurred vision - Beta blocker
2. Lignocaine - Artificial tears
3. Polyvinyl Alcohol - Local Anesthetic
4. Fluroscein - Mydriatic
5. Timolol - Staining

D. Write the uses of the following drugs

1. Paracetamol
2. Oral Rehydration Solution
3. Glyciphage
4. Cap. Nifedipine
5. Sorbitrate

E. Expand the following

1. Tds
2. SOS
3. H.S
4. Stat
5. Qid

F. Answer the following

1. List the rules to be followed while administering medication
2. Differentiate mydriatics and miotics
3. What are antibiotics?
4. What are anti hypertensives?
5. What are analgesics?
6. Explain briefly about antibiotics used in ophthalmology.
7. List the different modes of drug delivery
8. Differentiate topical and systemic medications
9. Differentiate trade name and chemical name
10. What are analgesics?
11. What are immunosuppressive drugs?
12. Name 2 immunosuppressive drugs
13. Place the following in proper order
• Check the doctor's instructions or prescriptions
• Expose palpebral conjunctiva
• Wash hands and dry
• Instruct the patient to open the eyes and look up
• Inspect the patient's lids to determine the need for cleaning

Practical skills

• Discuss the use and dispensing of drugs with your doctors.
• Learn from your doctor the ways to manage drug allergies and adverse reactions which have to be treated immediately.
• Collect the printed package, inserts of different drugs (most commonly used) from your hospital practice or from your pharmacy and read through it.
• Learn the technique of giving proper intra deltoid, intragluteal, intravenous and subcutaneous injections.