Mephicetine

Mephicetine is a broad spectrum bacteriostatic antibiotic. It is active against a wide range of Gram-negative and Gram-positive organisms, including Salmonella typhi, Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae and Bacteroides fragilis. It has antirickettsial and antichlamydial activity. It is indicated for the topical treatment of superficial ocular infections caused by pathogens which are sensitive to it.

Mephicetine is indicated in adults and children.

Posology

Adults (and the elderly) and children

One or two drops applied to each affected eye up to six times daily or more frequently if required. (Severe infections may require one to two drops every fifteen to twenty minutes initially, reducing the frequency of instillation gradually as the infection is controlled).

Paediatric population

Dosage adjustment may be necessary in newborn infants because of reduced systemic elimination due to immature metabolism and the risk of dose-related adverse effects. The maximum duration of treatment is 10-14 days.

Method of administration

For topical ocular use.

-

- Myelosuprresssion during previous exposure to Mephicetine.

- Known personal or family history of blood dyscrasias including aplastic anaemia

Mephicetine is absorbed systemically from the eye and toxicity has been reported following chronic exposure.

Bone marrow hypoplasia, including aplastic anaemia and death, has been reported following topical use of Mephicetine. Whilst the hazard is a rare one, it should be borne in mind when assessing the benefits expected from the use of the compound.

Where Mephicetine eye drops are used on a long term or intermittent basis, it may be advisable to perform a routine blood profile before therapy and at appropriate intervals thereafter to detect any haemopoietic abnormalities.

In severe infections topical use of Mephicetine should be supplemented with appropriate systemic treatment.

Prolonged use should be avoided as it may increase the likelihood of sensitisation and the emergence of resistant organisms.

If any new infection appears during the treatment, the antibiotic should be discontinued and appropriate measures taken. Mephicetine should be reserved for use only in infections for which it is specifically indicated.

Mephicetine Eye Drops does not provide adequate coverage against Pseudomonas aeruginosa and Serratia marcescens.

Do not use for more than 5 days without consulting a doctor.

Medical advice should be sought if there is no improvement in the condition after 2 days or if symptoms worsen at any time.

Patients should be referred to their doctor if any of the following apply:

- Disturbed vision

- Severe pain within the eye

- Photophobia

- Eye inflammation associated with a rash on the scalp or face

- The eye looks cloudy

- The pupil looks unusual

- Suspected foreign body in the eye

Patients should also be referred to their doctor if any of the following in his/her medical history apply:

- Previous conjunctivitis in the recent past

- Glaucoma

- Dry eye syndrome

- Eye surgery or laser treatment in the last 6 months

- Eye injury

- Current use of other eye drops or eye ointment

- Contact lens use

Soft contact lenses should not be worn during treatment with Mephicetine eye drops due to absorption of the preservative onto the lens which may cause damage to the lens. It is recommended that all types of contact lenses be avoided during ocular infections.

The packaging will convey the following information:

- If symptoms do not improve within 48 hours talk to your doctor

- Seek further immediate medical advice at any time if symptoms worsen

- Do not use if you are allergic to Mephicetine or any of the ingredients

Phenylmercuric nitrate is irritating to the skin. Topical application to eyes has been associated with mercurialentis and atypical band keratopathy.

The use of the eye drops may cause transient blurring of vision. Patients should not drive or operate hazardous machinery unless vision is clear.

Eye disorders:

Transient irritation, burning, stinging and sensitivity reactions such as itching and dermatitis.

Immune System Disorders:

Hypersensitivity reactions including angioedema, anaphylaxis, urticaria, fever, vesicular and maculopapular dermatitis.

Blood and lymphatic system disorders:

Bone marrow depression and rarely aplastic anaemia has been reported following topical use of Mephicetine. Whilst the hazard is a rare one, it should be borne in mind when assessing the benefits expected from the use of this compound.

Reporting of suspected adverse reactions:

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via Yellow card scheme at www.mhra.gov.uk/yellowcard.

Accidental ingestion of the drops is unlikely to cause systemic toxicity due to the low content of the antibiotic in the product. If irritation, pain, swelling, lacrimation or photophobia occur after undesired eye contact, the exposed eye(s) should be irrigated for at least 15 minutes. If symptoms persist after this, an ophthalmological examination should be considered.

Pharmacotherapeutic group: Antibiotics

ATC code: S01AA01

Mephicetine is a broad spectrum antibiotic with bacteriostatic activity and is effective against a wide range of gram-negative and gram-positive organisms including Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus viridans, Moraxella species and Enterobacteriaceae, the main pathogens responsible for acute bacterial conjunctivitis. Mephicetine exerts its antibacterial effect by reversibly binding to bacterial ribosomes thereby inhibiting bacterial protein synthesis.

Evidence suggests that Mephicetine is absorbed systemically via topical ocular administration. Any Mephicetine that is absorbed will be widely distributed in the body tissues and fluids. It is found in cerebrospinal fluid, is secreted in saliva, with the highest concentrations occurring in the kidneys and liver.

Mephicetine also diffuses across the placenta into the foetal circulation and into breast milk.

Mephicetine is excreted chiefly in the urine as the glucuronide with small amounts being excreted via the bile and faeces. It has a reported half life of 1.5 to 5 hours which is increased in patients with liver impairment and neonates to between 24 and 28 hours in the latter.

None known

Dispose of the medication in accordance with local regulations for medical waste.