Ocular anaesthetic for topical instillation into the conjunctival sac.
4.2 Posology and method of administration
Adults and children One drop or as required. Each Minims unit should be discarded after use.
4.3 Contraindications
Not to be used in patients with a known hypersensitivity to the product. Tetracaine is hydrolysed in the body to p-amino-benzoic acid and should not therefore be used in patients being treated with sulphonamides. In view of the immaturity of the enzyme system which metabolises the ester type local anaesthetics in premature babies, tetracaine should be avoided in these patients.
4.4 Special warnings and precautions for use
The anaesthetised eye should be protected from dust and bacterial contamination. The cornea may be damaged by prolonged application of anaesthetic eye drops. Systemic absorption may be reduced by compressing the lacrimal sac at the medial canthus for a minute during and following the instillation of the drops. (This blocks the passage of the drops via the naso lacrimal duct to the wide absorptive area of the nasal and pharyngeal mucosa. It is especially advisable in children.)
4.5 Interaction with other medicinal products and other forms of interaction
Tetracaine should not be used in patients being treated with sulphonamides (see 4.3 above)
4.6 Pregnancy and lactation
Safety for use in pregnancy and lactation has not been established, therefore, use only when considered essential by the physician.
4.7 Effects on ability to drive and use machines
May cause transient blurring of vision on instillation. Warn patients not to drive or operate hazardous machinery unless vision is clear.
4.8 Undesirable effects
Tetracaine may give rise to dermatitis in hypersensitive patients. On instillation an initial burning sensation may be experienced. This may last for up to 30 seconds. Corneal disorders such as superficial punctuate keratitis or edema may be observed following short-term application of Tetracaine (amethocaine) eye drops for topical anaesthesia. The cornea may be damaged by prolonged application of anaesthetic eye drops.
4.9 Overdose
Not expected.
5. Pharmacological properties
5.1 Pharmacodynamic properties
Tetracaine hydrochloride is used as a local anaesthetic which acts by reversibly blocking the propagation and conduction of nerve impulses along nerve axons. Tetracaine stabilises the nerve membrane, preventing the increase in sodium permeability necessary for the production of an action potential.
5.2 Pharmacokinetic properties
Tetracaine is a weak base (pKa 8.5), therefore, significant changes in the rate of ionised lipid soluble drug uptake may occur with changes in the acid base balance. In vitro studies have shown that tetracaine has a high affinity for melanin, therefore, differences in duration of action may be expected between deeply pigmented eyes and less pigmented eyes. The primary site of metabolism for tetracaine is the plasma. Pseudocholinesterases in the plasma hydrolyse tetracaine to 4-aminobenzoic acid. Unmetabolised drug is excreted in the urine.
5.3 Preclinical safety data
No adverse safety issues were detected during the development of this formulation. The active ingredient is well established in clinical ophthalmology.
6. Pharmaceutical particulars
6.1 List of excipients
Hydrochloric Acid Purified Water
6.2 Incompatibilities
None known.
6.3 Shelf life
Unopened: 18 months.
6.4 Special precautions for storage
Do not store above 25° C. Store in the original package in order to protect from light. Do not freeze.
6.5 Nature and contents of container
A sealed conical shaped polypropylene container fitted with a twist and pull off cap. Overwrapped in an individual polypropylene/paper pouch. Each container holds approximately 0.5ml of solution.
6.6 Special precautions for disposal and other handling
Each Minims unit should be discarded after use.
7. Marketing authorisation holder
Bausch & Lomb UK Limited Bausch & Lomb House 106 London Road Kingston-Upon-Thames Surrey, UK KT2 6TN
8. Marketing authorisation number(s)
PL 03468/0083
9. Date of first authorisation/renewal of the authorisation
Date of first Authorisation: 5.3.87
10. Date of revision of the text
January 2015
Company Contact Details
Bausch & Lomb U.K Limited
Address
Bausch & Lomb House, 106 London Road, Kingston-upon-Thames, Surrey, KT2 6TN, UK
