Important aspects of prescribing information relevant to primary healthcare are covered in this section specifically for the drugs recommended in this CKS topic. For further information on contraindications, cautions, drug interactions, and adverse effects, see the electronic Medicines Compendium (eMC) (http://emc.medicines.org.uk), or the British National Formulary (BNF) (www.bnf.org).

Table 1 lists the tear replacement and ocular lubricant products available in the UK.

• The severity of the condition and the person's preference should guide the choice of artificial tears and ocular lubricants:
• Mild or moderate symptoms — artificial tears alone are usually sufficient:
• Hypromellose is the most commonly used product, but it requires frequent administration (at 30-minute intervals until symptoms improve, then frequency can be decreased).
• Products containing carbomers or polyvinyl chloride are longer acting.
• Sodium chloride is short acting and suitable as 'comfort drops' or for use with contact lenses.
• If a product is used very frequently (e.g. more than six applications daily) or causes irritation, or if soft contact lenses are worn, consider switching to one that is preservative free, as these cause less irritation. Hypromellose, carbomers, polyvinyl chloride, sodium chloride, carmellose sodium, hydroxyethylcellulose, and povidone are available without preservatives.
• Severe symptoms — preservative-free artificial tears are suitable (to avoid irritation caused by preservatives). Consider adding an ocular lubricant ointment for use at night.
• Visible strands of mucus — consider prescribing acetylcysteine drops.
• For further information on the management of dry eye syndrome, including use of conservative (self-care) measures, and for the rationale for using artificial tears and ocular lubricants, see the CKS topic on Dry eye syndrome.

[Khaw et al, 2004; American Academy of Ophthalmology, 2006; BNF 54, 2007; DEWS, 2007]

• Artificial tears control symptoms and limit damage to the eyes. A large range of products is available on prescription or over-the-counter. Advise that if an individual product proves unsuitable, another one may be tried. For further information on which product may be suitable, see Choice of artificial tears and ocular lubricants.
• Eye ointments containing paraffin may be uncomfortable and blur vision; thus, they should only be used at night, and never with contact lenses.
• Acetylcysteine eye drops may sting briefly.

[Khaw et al, 2004; BNF 54, 2007]

• Topical chloramphenicol eye ointment is preferred unless:
• Other eye drops are being used concurrently (e.g. for glaucoma).
• Topical chloramphenicol is contraindicated (see Prescribing topical antibiotics).
• There is a coexisting disorder affecting the cornea (e.g. conjunctivitis).
• The person wears contact lenses. Ideally, these should not be worn during treatment, but if the person cannot avoid wearing them, consider prescribing preservative-free chloramphenicol eye drops (some preservatives, such as benzalkonium chloride, accumulate in soft contact lenses, and may cause irritation).
• If topical chloramphenicol ointment is unsuitable, consider prescribing chloramphenicol or fusidic acid eye drops. However, these may be less effective, as they will be in contact with the lid margin for less time.

[American Optometric Association, 2002; American Academy of Ophthalmology, 2003]

Chloramphenicol:

• Do not use topical chloramphenicol:
• In people who have experienced myelosuppression during previous exposure to chloramphenicol.
• In people who have a blood dyscrasia or who have a family history of blood dyscrasias.
• Concurrently with other myelotoxic drugs.
• In pregnant women (owing to the possibility of grey baby syndrome). However, it may be used in breastfeeding women [UKMiCentral, 2004].
• Topical chloramphenicol is relatively well tolerated. Aplastic anaemia and bone marrow depression are very rare, and concerns about the increased risk of this adverse effect are probably unfounded [Walker et al, 1998].

[ABPI Medicines Compendium, 2007a; ABPI Medicines Compendium, 2007b; BNF 54, 2007; ABPI Medicines Compendium, 2008]

Fusidic acid:

• People who wear contact lenses should avoid topical fusidic acid, as it contains preservatives (benzalkonium chloride).
• Topical fusidic acid has no reported serious adverse effects.

[ABPI Medicines Compendium, 2001; BNF 54, 2007]

• Give advice about applying the topical antibiotic:
• Antibiotic ointment or drops should be applied after eyelid hygiene and/or at night before sleep. The frequency of application depends on the severity of the blepharitis and its response to treatment. As the condition improves, application can be reduced to once daily [American Academy of Ophthalmology, 2003].
• The antibiotic should be rubbed into the lid margin using a finger tip or cotton bud. As with eyelid hygiene, care should be taken not to traumatize the skin in this process [Smith and Flowers, 1995]. If an ointment is being used as recommended, it should be used sparingly, with care taken to avoid contamination of the eye.
• The duration of treatment depends on the severity and response of the blepharitis. Experts recommend treating for 1 month after the inflammation has subsided, although there is no evidence from clinical trials to guide the length of treatment. If response is poor after a prolonged period (e.g. 6 weeks), the person should seek further medical advice.
• Inform the person that:
• Adverse effects are usually minor, such as transient stinging or a burning sensation in the eye.
• Driving should be avoided if ointment causes blurred vision.
• Contact lenses should be avoided where possible (if this is not possible, see Choice of topical antibiotic).
• If two different eye-drop preparations are used at the same time of day, an interval of at least 5 minutes should be left between application of the two types. This will help prevent any dilution and overflow that may occur if application of one preparation immediately follows another.

[ABPI Medicines Compendium, 2001; ABPI Medicines Compendium, 2007a; ABPI Medicines Compendium, 2007b; BNF 54, 2007; ABPI Medicines Compendium, 2008]

• Tetracyclines are not specifically licensed for the treatment of blepharitis. Tetracycline and oxytetracycline are licensed for the treatment of rosacea which often accompanies chronic blepharitis; doxycycline and lymecycline are not licensed for rosacea [BNF 54, 2007].
• Because evidence from controlled trials and product information are lacking, the optimal regimen of tetracyclines in the treatment of blepharitis is based on expert opinion. In general, low doses are initiated (compared with doses used for acute infections), as they are being used in an anti-inflammatory role rather than as an antibiotic. After the condition has improved noticeably (usually after 2–4 weeks), the dose can be further reduced for maintenance [American Academy of Ophthalmology, 2003].
• Treatment should be continued for at least 6 weeks. However, clinical experience has shown that longer courses of tetracyclines (e.g. 3 months) may provide better responses [Dart, Personal Communication, 2004].
• Table 1 lists the doses of tetracyclines for the treatment of blepharitis, as recommended by CKS.

• Do not use tetracyclines in:
• Pregnant or breastfeeding women, or children younger than 12 years of age. Tetracyclines are deposited in the teeth and bones of the unborn or developing child.
• People with renal failure, with the exception of doxycycline. Tetracycline, oxytetracycline, and lymecycline are excreted renally; doxycycline is a safer option in this group.
• Avoid use of doxycycline if the person is likely to be exposed to excessive sunlight (e.g. working outdoors or on holiday in a sunny climate) or ultraviolet light from another source, owing to the risk of photosensitivity [ABPI Medicines Compendium, 2006a]. Photosensitivity may also occur with tetracycline, oxytetracycline, and lymecycline, but probably to a lesser extent [Wolf, 2002].

[BNF 54, 2007]

• Advise the person to stop treatment and seek medical advice if they develop severe headache and/or visual disturbances. This may be an early symptom of benign intracranial hypertension, a rare but serious adverse effect of tetracycline-like drugs.
• Inform the person that most adverse effects are not serious:
• Gastrointestinal disturbances are the most common:
• Nausea, vomiting, and diarrhoea are the most common symptoms.
• Tetracycline and oxytetracycline should be taken on an empty stomach, which may increase nausea (in particular, milk or antacids should be avoided). Doxycycline and lymecycline may be taken with food, which may help the person tolerate the drug.
• Tetracyclines can cause severe oesophagitis, presenting as a burning pain in the in the lower chest. To counteract this, recommend taking tetracyclines in an upright position with plenty of water, without chewing or breaking the tablets or capsules.
• Indigestion remedies, such as antacids (or medicines containing iron or zinc), should not be taken within 2–3 hours of tetracyclines.
• Advise women that:
• Yeast infections, such as vulvovaginal candidiasis, may occur initially as a result of the broad-spectrum nature of tetracyclines, but this should be minimal owing to the low doses used and extended course.
• Treatment of blepharitis with tetracyclines is rarely necessary in a woman of childbearing age. However, if the woman is taking the combined oral contraceptive pill, advise her that treatment may decrease the effectiveness of the contraceptive. For more information, see Antibiotics in the CKS topic on Contraception.
• Advise people to avoid excessive exposure to sunlight and sunbeds, especially if they are taking doxycycline.

[ABPI Medicines Compendium, 2006a; ABPI Medicines Compendium, 2006b; BNF 54, 2007]