1.  Disorders of the Ear

Removal of Ear Wax

Wax (cerumen) in the ear is normal and it helps to protect the lining of the outer ear. It only needs removing if there is so much that it is causing deafness or if the doctor cannot examine the ear drum properly in a patient with some other ear complaint. To clean the wax out, the ear should be syringed with warm water by a doctor or nurse. If the wax is very hard, it can be softened before syringing by applying sodium bicarbonate ear drops, warm olive oil or almond oil. Preparations that contain a wetting agent (eg. docusate sodium) or urea hydrogen peroxide may be equally effective.

Ear drops used to remove wax from the ears include:

• Cerumol (chlorbutanol, paradichlorobenzene, arachis oil)
• Exterol (urea hydrogen peroxide, hydroxyquinoline and glycerol)
• Molcer (docusate sodium)
• Otex (urea hydrogen peroxide, hydroxyquinoline and glycerol)
• sodium bicarbonate (sodium bicarbonate in glycerol)
• Waxsol (docusate sodium)

Inflammation of the Outer Ear (Otitis Externa)

Otitis externa is inflammation of the skin lining the outer ear canal, caused by eczema and/or infection. Acute attacks are treated by drying and cleaning the ear and the application of a ribbon gauze (gauze wick) soaked in aluminium acetate solution to dry the surface, or a weak solution of a corticosteroid to relieve any inflammation. Chronic otitis externa is often accompanied by a discharge, itching and irritation. Cleaning, drying and drying drops (aluminium acetate solution) may help. Corticosteroid drops (betamethasone (Betnesol, Vista-methasone), prednisolone (Predsol)) are very helpful and if infection and inflammation are present a combined corticosteroid/antibacterial preparation should be used. Combined corticosteroid/antibacterial preparations include: betamethasone/neomycin (Betnesol-N, Vista-Methasone-N), dexamethasone/neomycin (Otomize), dexamethasone/framycetin/gramicidin (Sofradex), flumetasone/clioquinol (Locorten-Vioform), hydrocortisone/gentamicin (Gentisone HC), hydrocortisone/neomycin (Neo-Cortef), hydrocortisone/neomycin/polymyxin B (Otosporin), prednisolone/neomycin (Predsol-N), triamcinolone/neomycin (Audicort), triamcinolone/gramicidin/neomycin/nystatin (Tri-Adcortyl Otic). Infection should be treated with a topical non-systemic broad spectrum antibacterial drug (chloramphenicol, gertamicin (Cidmycin, Garamycin, Genticin)). Treatment for more than one week may trigger a fungus infection which can be very difficult to treat. Allergy to the antibiotic or solvent may occur and resistance to the antibiotic may develop. If a fungal infection is suspected, an antifungal drug eg. clotrimazole (Canasten solution) should be added to the treatment.

Corticosteroids rapidly reduce swelling when applied to an inflamed non-infective otitis externa. They should be used with caution for long-term treatment and prolonged treatment in pregnancy should be avoided. Prolonged use of topical corticosteroid and antibacterials should be avoided because of the risk of the antibacterial producing damage to the ear (eg. hearing loss) and bacterial resistance to the antibiotic (p.000). If a fungal infection is suspected, an antifungal drug (eg. clotrimazole (Canestan Ear)) should be used, alone or in combination with an antibacterial drug. Patients suffering from otitis externa should have their ear drums examined carefully to see if there is a perforation, because sometimes a discharge may come from the middle ear through a perforation in the ear drum. In these patients, it is important to be careful and not to apply antibacterial drugs to the outer ear which, if they were to enter the middle ear, could cause deafness; for example, the antibiotics framycetin, gentamicin, neomycin, or polymyxin, or the antiseptic chlorhexidine.

Chlorine salicylate (Audax) is a mild analgesic which is of doubtful benefit when applied locally.

Inflammation of the Middle Ear (Otitis Media)

Infection in the middle ear causes pain, often with fever and deafness. Pain should be treated with paracetamol. If it is caused by a virus no antibiotic treatment is necessary; if it is bacterial then antibiotics should be given immediately. An injection of benzylpenicillin(penicillin G) (Crystapen) should be given to start treatment and then phenyloxymethylpenicillin(penicillin V) (Aspin, Tenkicin) by mouth. Treatment should continue for 5–10 days. Recurrent otitis media should be prevented by giving an antibacterial drug daily during the winter months, e.g. trimethoprim or erythromycin.

2.  Disorders of the Eyes

Antibacterial Drugs Applied to the Eyes

As with antibacterial drugs used to treat skin and ear disorders, those antibiotics which are never, or seldom, used internally, should be used. This is to reduce the risk of the patient becoming allergic to an antibiotic applied topically to the eyes and then subsequently running the risk of a serious allergic reaction if that drug is then taken by mouth or injection at some future date.

Antibiotics with a wide spectrum of activity against bacteria are used locally. They include chloramphenicol (Chloromycetin, Sno Phenicol), ciprofloxacin (Ciloxan), framycetin (Soframycin), gentamicin (Cidomycin, Garamycin, Genticin), lomefloxacin (Okacyn), neomycin (Neosporin), ofloxacin (Exocin). Gentamicin is effective against a particularly nasty infection caused by Pseudomonas aeruginosa and fusidic acid (Fucithalmic) is effective against bacteria that also cause boils (staphylococcus). Chlortetracycline (Aureomycin) and tetracycline are used to treat chlamydial infections of the eyes including trachoma.

Antiviral Drugs Applied to the Eyes

The herpes simplex virus that produces cold sores can infect the eyes, producing ulcers of the cornea; so too can the herpes zoster virus that produces shingles. They are treated with acyclovir (Zovirax) applications.

Retinitis caused by the cytomegalovirus in patients with AIDS can be treated with fomivirsen (Vitravene) which is administered by injection into the eye.

Corticosteroid Drugs Applied to the Eyes

The most effective anti-inflammatory drugs used to treat inflammatory conditions of the eyes are the corticosteroids. They are used to reduce inflammation in inflamed and allergic eye diseases and to reduce inflammation following eye surgery. They may be used as local applications, local injections under the conjunctivae or by mouth. They include betamethasone (Betnesol, Vista-Methasone), clobetasone (Cloburate), dexamethasone (Maxidex), fluorometholone (FML), hydrocortisone (Neo-Cortef), prednisolone (Pred Forte, Predsol), rimexolone (Vexol).

It is very important to restrict the use of corticosteroid eye preparations and not to use them to treat acute red eye (e.g. allergic or bacterial conjunctivitis) or to treat inflammation of the eyelids. A corticosteroid should only be used after a full eye examination has been carried out (including sight test) and fluorescein eye drops have been inserted in the eye to check for any ulcers or scarring of the cornea. If these are present the patient should be referred to an eye specialist. The patient should also see an eye specialist if there is no improvement after 1–2 weeks of treatment.

Corticosteroids applied to the eye can lower defence mechanisms and make an eye infection worse, particularly if it is due to a viral or fungal infection. They may lower resistance to an infection, especially to bacteria. If corticosteroid applications are used over the long term they may cause thinning of the cornea, perforation, raised pressure in the eye (glaucoma) and cataracts. Long term use in young people may produce generalised toxic effects (see Chapter 37). Therefore, the use of a corticosteroid and an anti-infective combined is rarely justified.Those commonly prescribed are betamethasone/neomycin (Betnesol-N, Vista-Methasone N), dexamethasone/neomycin/polymyxin (Maxitrol), dexamethasone/framycetin/gramicidin (Sofradex), prednisolone/neomycin (Predsol-N).

Anti-inflammatory Drugs Applied to the Eyes

Ketorolac trometamol (Acular eye drops) are used to prevent and reduce inflammation of the eye following surgery.

Anti-allergy Drugs Applied to the Eyes

Eye drops containing an antihistamine may help to relieve the redness and itching of allergic conjunctivitis, for example, antazoline (Optilast) combined with a decongestant xylometazoline (Otrivine-Antistin), but they should only be used for a few days at a time. Levocabastine (Livostin eye drops) is an antihistamine applied topically that is quick to act and produces prolonged effects. Emedastine (Emadine), lodoxamide (Alomide), nedocromil (Rapitil) and sodium cromoglycate (Clariteyes, Hay-crom, Opticrom, Optrex Allergy, Viz-on, Vividrin) are effective anti-inflammatory/anti-allergy drugs.

Soothing Eye Applications

Soothing preparations are included in eye drops to soothe and relieve irritation. The safest ones to use are polymers which are soluble in water (e.g. hypromellose).

Drugs Used to Treat Dry Eyes

Eye lubricants include carmellose (Celluvisc), hypromellose (Artelac, Isopto preparations, Tears Naturale), polyacrylic acid (Gel Tears, Viscotears), hydroxymethylcellulose (Minims Artificial Tears), liquid paraffin (Lacri-Lube, Lubri-Tears), polyvinyl alcohol (Hypotears, Liquifilm Tears, Sno Tears) and povidone (Oculotect). Acetylcysteine (Ilube) helps to lubricate and also break down mucus.

Other Preparations

Sodium chloride solution (sterile) is useful for washing out the eyes and zinc sulphate eye drops have been used to dry the eyes. Decongestant eye drops (ephedrine, naphazoline and phenylephrine) relieve congestion but repeated use can cause redness of the eyes.

Drugs which Work on the Pupils

Drugs which Dilate the Pupils

Drugs which dilate the pupils are called mydriatics. They cause the pupil to dilate by paralysing the circular muscles of the iris, by stimulating it to contract or by a mixture of both actions. Those that paralyse the circular muscles may be referred to as cycloplegics and they may produce prolonged effects.

Anticholinergic drugs (see Chapter 9) produce these effects and they are used in eye drops to dilate the pupils. Short-acting anticholinergic drugs such as tropicamide (Mydriacyl) are used by eye specialists to dilate the pupils so that they can examine the inside of the eyes more easily. Longer-acting anticholinergic drugs are used to rest the pupil in patients who have an infection of the pupil. The effects of tropicamide last about 3 hours; cyclopentolate and homatropine about 24 hours, and the effects of atropine may last for over a week.

Drugs that Constrict the Pupils

Drugs that cause the pupils to constrict (become small) are called miotics. They act in an opposite way to the anticholinergic drugs. They constrict the muscle that works the iris, so that the pupil becomes small and opens up the drainage canal in the front chamber of the eye. They are used to constrict the pupil after a patient has had a mydriatic applied to dilate the pupil for an eye examination, particularly in patients over the age of forty, in order to avoid the risk of triggering off an attack of glaucoma. They are also used to treat open-angle glaucoma in order to reduce the pressure in the front of the eye (see below).

Drugs that constrict the pupils (miotics) include drugs which act like acetylcholine, for example carbachol and pilocarpine (Ocusert, Pilogel), and drugs that delay the breakdown of acetylcholine, for example, physostigmine and ecothiopate. For a discussion of the actions and effects produced by these drugs, read Chapter 9.

Warning: Drugs which constrict the pupils and are applied to the eyes may be absorbed directly into the blood-stream. Also, eye drops may run down the nose and down the cheek into the mouth and be absorbed from the nose or mouth into the blood-stream. Therefore, they may produce generalized harmful effects which include increased salivation, sweating, slow heart rate, stomach pains and wheezing.

Glaucoma

Glaucoma is a term used to describe an increase in pressure inside the eye and the damage that it produces. About 1 person in 100 over forty years of age develops glaucoma, and about 5 in 100 of those over sixty-five years.

In glaucoma the pressure of the fluid in the front chamber of the eyes (between the lens and the cornea) is raised due to a defective draining away of the fluid while the inflow remains steady. The increase in pressure affects the transparency of the cornea (the window of the eye) and compresses the blood vessels that supply the main optic nerve that links the eye to the brain. The latter may produce irreversible damage to the optic nerve resulting in a permanent loss of vision. This loss of vision may come on suddenly over a few days or may develop slowly over years.

There are two principal types of glaucoma – open-angle and closed-angle glaucoma.

1. Open-angle Glaucoma (Chronic Simple Glaucoma)

This is the commonest type of glaucoma. It comes on slowly and is commonest in elderly people. The increase in pressure is caused by a decreased outflow from the front chamber of the eye which probably results from a degeneration of the outlet mechanisms. It causes no early symptoms but may lead to a slow and progressive reduction in the outer fields of vision (the peripheral vision) and eventually to blindness. Both eyes are nearly always affected, although one eye may be more severely affected than the other and the loss of vision may not be noticed for months or years. There is no pain with open-angle glaucoma and no sudden onset of symptoms.

2. Closed-angle Glaucoma (Narrow-angle Glaucoma;

Acute Glaucoma, Congestive Glaucoma)

This develops when the drainage of fluid from the front chamber of the eye is suddenly blocked. This may occur in patients who are predisposed to develop closed-angle glaucoma because they have a small eyeball in which the drainage angle for fluid in the front chamber of the eye between the iris and the lens is very narrow and it may easily become closed off by a swelling of the iris or lens (i.e. ‘closed-angle’). When the pupil dilates, the circular muscles of the iris are more bulky than when the pupil is constricted. This bulkiness may block off the narrow angle between the iris and the lens and interfere with the drainage of fluid. A number of drugs may close this angle by causing dilation of the pupil and may trigger off an acute attack in someone prone to develop glaucoma.

When the angle is blocked the pressure builds up rapidly and the patient complains of a sudden onset of blurred vision, perhaps preceded by seeing haloes around objects, severe pain in the affected eye and usually some headache, nausea and vomiting. On examination the pressure in the affected eye is found to be increased and there is a loss of vision, the eye is red and painful, and the pupil looks cloudy. It may be very serious and requires immediate treatment from an eye specialist.

Drugs which may Trigger off an Attack of Glaucoma in Patients Prone to Develop Closed-angle Glaucoma  

• anticholinergic drugs (e.g. atropine and hyosine)
• antihistamines
• chlorpropamide used to treat diabetes
• corticosteroids
• cough and cold remedies containing anticholinergic drugs, and/or antihistamines
• fenfluramine used as a slimming drug
• ganglion blocking drugs used to treat raised blood pressure (e.g. hexamethonium)
• indomethacin used to treat rheumatoid arthritis
• monoamine oxidase inhibitor antidepressants
• oral contraceptives
• tricyclic and cyclic antidepressant drugs.

Treatment of Glaucoma

Drugs Used to Treat Glaucoma and How They Work

Miotic eye drops (e.g. carbachol, pilocarpine (Ocusert, Pilogel) decrease the pressure in the front chamber of the eye by improving the drainage of the fluid. Unfortunately, they constrict the pupil and may produce blurring of vision and an aching in the brow.

Adrenaline(epinephrine) (Eppy, Simplene) eye drops help to improve the drainage of fluid in the front chamber of the eye and may decrease its rate of production. The net result is a reduction in the pressure in the eye. Adrenaline(epinephrine) may produce severe smarting and redness of the eye and it should not be used in closed-angle glaucoma (see earlier) because adrenaline(epinephrine) dilates the pupil and this may interfere with drainage. Dipivefrine (Propine) eye drops are formulated to pass quickly through the cornea and enter the fluid in the front chamber of the eye where the dipivefrine is converted into adrenaline(epinephrine). Adrenaline(epinephrine) and related preparations applied to the eye reduce the production of fluid in the anterior chamber and increase its drainage. They have minimal effects on the heart and circulation and do not affect breathing.

Brimonidine (Alphagan) and apraclonidine (Iopidine) are Alpha₂-Adrenoceptor Stimulants. Brimonidine is more selective in its actions than apraclonidine and does not cause blanching of the conjunctivae or mydriasis. They are used in the treatment of open-angle glaucoma or hypertension in the eye.

Guanethidine (Ganda) is used to treat raised blood pressure (see Chapter 25). It is applied as eye drops to treat glaucoma because it helps to reduce the pressure inside the eye by slowing the rate of production of the fluid in the front chamber of the eye and increasing its drainage outflow. It has a slow constricting effect on the pupil, although at first it may cause the pupil to dilate. It increases and prolongs the effects of adrenaline(epinephrine).

Beta-blockers are discussed in detail in Chapter 22. Several are used as eye drops for treating glaucoma. They are thought to reduce the pressure inside the eye by reducing the rate of production of the fluid in the front chamber of the eye.

Beta-blockers used as eye drops include the selective blocker betaxolol (Betoptic), and the non-selective blockers carteolol (Teoptic), levobunolol (Betagan), metipranolol and timolol (Timoptal).

Like any drug applied to the eyes, beta-blockers may be absorbed directly into the blood-stream and also from the nose and mouth if the drops run into them. This absorption may produce harmful effects, particularly in patients who suffer from asthma; in patients with a slow heart rate; and in patients with heart failure because they may make the condition worse. A sufficient amount of drug may also be absorbed to interact with other drugs: for example, with the drug verapamil, used to treat angina and disorders of heart rhythm. The absorbed beta-blocker may interact with the verapamil to cause a fall in blood pressure, heart failure and may, very rarely, stop the heart from beating. Beta-blocker eye drops may produce dry eyes, conjunctivitis and allergic inflammation of the eyelids.

Diuretics (water tablets) are discussed in detail in Chapter 29. One of these drugs, acetazolamide (Diamox) is used to reduce the pressure in the eye. It reduces the volume of fluid in the front chamber of the eye by blocking the production of bicarbonate which causes a reduction in the production of water into the fluid.

Dorzolamide (Trusopt, in Cosopt) and brinzolamide (Azopt) are diuretics similar to acetazolamide that can be applied directly to the eye instead of being taken by mouth.

The prostaglandin analogue latanoprost (Xalatan) increases the outflow of fluid from the eye. It is used for open-angle glaucoma and hypertension in the eye when other drugs are inappropriate. Latanoprost can affect the colour of the eyes increasing the brown colour. Therefore, particular care is required in patients with mixed coloured eyes or when only one eye is being treated.

Drug Treatment of Open-angle Glaucoma (Chronic Simple Glaucoma)

In this condition drug treatment is used to reduce the pressure inside the eye and to maintain this pressure at a normal level, usually for the rest of the patient’s life. Effective drug treatment (if taken as directed) prevents further deterioration in vision, but of course it cannot restore any damage that has already occurred and this is why early diagnosis is important.

Treatment usually starts with beta-blocker eye drops (see above) to reduce the rate of production of fluid in the eye and then a drug which constricts the pupil and improves drainage of fluid from the eye may be added. Pilocarpine (Ocusert, Pilogel) is one of the most commonly used drugs for this purpose and it is often preferred in older patients. However, younger people and short-sighted people may find that the constriction of the pupil produced by pilocarpine affects their vision, while other people may find that the drops actually help them to focus. Over time it may be necessary to add adrenaline(epinephrine) (Eppy, Simplene) to the beta-blocker and pilocarpine.

Because pilocarpine constricts the pupils, anyone who has a disorder of the lens (e.g. early cataract) may find that their vision is further impaired. In these patients it is best to try a beta-blocker first and then add adrenaline(epinephrine) eye drops if necessary.

If these treatments are not beneficial the addition of acetazolamide (Diamox) by mouth may help. An alternative is dorzolamide (Trusopt) eye drops which may be given on its own if beta-blockers are contra-indicated or are ineffective or as additional treatment to beta-blockers. A combination product of dorzolamide with timolol (Cosopt), a beta-blocker, is available.

Drug Treatment of Acute (Closed-angle) Glaucoma

A person who has developed acute glaucoma needs urgent medical treatment in order to prevent loss of vision. Drugs are used to bring down the pressure in the eyes and then laser treatment or surgery may be carried out to provide drainage of the fluid and to prevent a recurrence of the problem. It is not usual for drug treatment to be continued for very long.

Acetazolamide (Diamox) is normally the first drug to be given, at first by injection and then by mouth. Eye drops to constrict the pupil are then applied at frequent intervals and occasionally a thiazide or other osmotic diuretic is given by mouth (see Chapter 29) to draw fluid out of the tissues.

Other Eye Preparations

For diagnostic purposes fluorescein sodium and rose bengal are both used. They stain the eye and are used for locating any damaged areas of the cornea.

Diclofenac (Voltarol Optha) and flurbiprofen (Ocufen) are anti-inflammatory drugs used to reduce inflammation in the eye following surgery.