1. Name Of The Medicinal Product
Minims Phenylephrine Hydrochloride 2.5%
2. Qualitative And Quantitative Composition
Clear, colourless, sterile eye drops containing Phenylephrine Hydrochloride Ph.Eur. 2.5% w/v.
3. Pharmaceutical Form
Sterile, single-use eye drop
4. Clinical Particulars
4.1 Therapeutic Indications
Phenylephrine is a directly acting sympathomimetic agent used topically in the eye as a mydriatic. It may be indicated to dilate the pupil for diagnostic or therapeutic procedures.
4.2 Posology And Method Of Administration
Adults
Apply one drop topically to each eye. If necessary, this dose may be repeated once only, at least one hour after the first drop.
The use of a drop of topical anaesthetic a few minutes before instillation of phenylephrine is recommended to prevent stinging.
Children and the Elderly
Apply one drop topically to the eye. It is not usually necessary to exceed this dose.
4.3 Contraindications
Patients with cardiac disease, hypertension, aneurysms, thyrotoxicosis, long-standing insulin dependent diabetes mellitus and tachycardia.
Patients on monoamine oxidase inhibitors, tricyclic antidepressants and anti-hypertensive agents (including beta-blockers).
Patients with closed angle glaucoma (unless previously treated with iridectomy) and patients with a narrow angle prone to glaucoma precipitated by mydriatics.
Hypersensitivity to phenylephrine or any component of the preparation.
4.4 Special Warnings And Precautions For Use
Use with caution in the presence of diabetes, cerebral arteriosclerosis or long-standing bronchial asthma.
To reduce the risk of precipitating an attack of narrow angle glaucoma evaluate the anterior chamber angle before use.
Ocular hyperaemia can increase the absorption of phenylephrine given topically.
Corneal clouding may occur if phenylephrine 10% is instilled when the corneal epithelium has been denuded or damaged.
Systemic absorption may be minimised by compressing the lacrimal sac at the medial canthus for one minute during and after 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
Anti-hypertensive Agents
Topical phenylephrine should not be used as it may reverse the action of many anti-hypertensive agents with possibly fatal consequences.
Monoamine Oxidase Inhibitors
There is an increased risk of adrenergic reactions when used simultaneously with, or up to three weeks after, the administration of MAOIs.
Tricyclic Antidepressants
The pressor response to adrenergic agents and the risk of cardiac arrythmia may be potentiated in patients receiving tricyclic antidepressants (or within several days of their discontinuation).
Halothane
Because of the increased risk of ventricular fibrillation, phenylephrine should be used with caution during general anaesthesia with anaesthetic agents which sensitise the myocardium to sympathomimetics.
Cardiac Glycosides or Quinidine
There is an increased risk of arrythmias.
4.6 Pregnancy And Lactation
Safety for use during pregnancy and lactation has not been established. This product should only be used during pregnancy if it is considered by the physician to be essential.
4.7 Effects On Ability To Drive And Use Machines
May cause stinging and temporarily blurred vision. Warn patients not to drive or operate hazardous machinery until vision is clear.
4.8 Undesirable Effects
Local
Eye pain and stinging on instillation (use of a drop of topical anaesthetic a few minutes before the instillation of phenylephrine is recommended), temporarily blurred vision and photophobia, conjunctival sensitisation and allergy may occur.
Systemic
Palpitations, tachycardia, extrasystoles, cardiac arrythmias and hypertension.
Serious cardiovascular reactions including coronary artery spasm, ventricular arrythmias and myocardial infarctions have occurred following topical use of 10% phenylephrine. These sometimes fatal reactions have usually occurred in patients with pre-existing cardiovascular disease.
4.9 Overdose
Because a severe toxic reaction to phenylephrine is of rapid onset and short duration, treatment is primarily supportive. Prompt injection of a rapidly acting alpha-adrenergic blocking agent such as phentolamine (dose 2 to 5mg iv) has been recommended.
5. Pharmacological Properties
5.1 Pharmacodynamic Properties
Phenylephrine is a direct acting sympathomimetic agent. It causes mydriasis via the stimulation of alpha receptors. There is almost no cycloplegic effect.
Maximal mydriasis occurs in 60 - 90 minutes with recovery after 5 - 7 hours.
The mydriatic effects of phenylephrine can be reversed with thymoxamine.
5.2 Pharmacokinetic Properties
Phenylephrine is a weak base at physiological pH. The extent of ocular penetration is determined by the condition of the cornea. A healthy cornea presents a physical barrier, in addition to which, some metabolic activity may occur. Where the corneal epithelium is damaged, the effect of the barrier and the extent of metabolism are reduced, leading to greater absorption.
5.3 Preclinical Safety Data
The use of phenylephrine in ophthalmology has been well established for many years. No unexpected adverse safety issues were identified during the development of the Minims format.
6. Pharmaceutical Particulars
6.1 List Of Excipients
Sodium metabisulphite
Disodium edetate
Purified water
6.2 Incompatibilities
None stated.
6.3 Shelf Life
15 months.
6.4 Special Precautions For Storage
Store below 25°C. Do not freeze. Store in the original container in order to protect from light.
6.5 Nature And Contents Of Container
A sealed conical shaped polypropylene container fitted with a twist and pull off cap. Each Minims unit is 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 a single use.
7. Marketing Authorisation Holder
Chauvin Pharmaceuticals Ltd
106 London Road
Kingston-upon-Thames
Surrey
KT2 6TN
8. Marketing Authorisation Number(S)
PL 0033/0117
9. Date Of First Authorisation/Renewal Of The Authorisation
21/05/1986
10. Date Of Revision Of The Text
September 2006
No comments:
Post a Comment