Hyason

Hyason can be used to enhance permeation of subcutaneous or intramuscular injections, local anaesthetics and subcutaneous infusions and to promote resorption of excess fluids and blood in the tissues.

Adults, children and the elderly:

With subcutaneous infusion (hypodermoclysis): 1500iu of Hyason dissolved in 1ml of water for injections or normal saline injected into the site, before the infusion is set up, or injected into the tubing of the infusion set, about 2cm back from the needle, at the start of the infusion. 1500iu is sufficient for administration of 500-1000ml of most fluids. Care should be taken in young children and the elderly to control the speed and total volume of fluid administered and to avoid over-hydration, especially in renal impairment.

With subcutaneous or intramuscular injections: 1500iu of Hyason dissolved directly in the solution to be injected.

With local anaesthetics: 1500iu Hyason is mixed with the quantity of local anaesthetic solution to be used. In ophthalmology, 15iu of Hyason per ml is recommended.

Extravasation: Where dispersal rather than localisation is indicated, 1500iu of Hyason in 1ml water for injections or normal saline infiltrated into the affected area as soon as possible after the extravasation is noted.

Haematoma: 1500iu of Hyason dissolved in 1ml water for injections or normal saline infiltrated into the affected area.

Immediately before use dissolve the freeze-dried powder in approximately 1ml of water for injections or directly in the solution with which Hyason is to be combined.

Hypersensitivity to Hyason.

Not to be used for intravenous injections.

Not to be used to reduce the swelling of bites or stings or at sites where infection or malignancy is present.

Not to be used for anaesthetic procedures in cases of unexplained premature labour.

Do not apply directly to the cornea.

Hyason should not be used to enhance the absorption and dispersion of dopamine and/or alpha agonist drugs.

Solutions for subcutaneous administration should be isotonic with extracellular fluid. Hyason is physically compatible with the commonly used infusion fluids. Use in hypodermoclysis has been reported with 0.9% sodium chloride, 0.18% sodium chloride with 4% glucose, 0.45% sodium chloride with 2.5% glucose and 5% glucose.

Potassium 34mmol/litre has been administered by hypodermoclysis in isotonic glucose or saline with 1500 I.U/litre Hyason.

Electrolyte-free fluids are less preferable than those containing electrolytes and should not be given too rapidly. Hyason has also been mixed with morphine, diamorphine, hydromorphone, chlorpromazine, metoclopramide, promazine, dexamethasone, local anaesthetics and adrenaline (see 6.2. Incompatibilities).

None known.

Oedema has been reported in association with hypodermoclysis. Allergic reactions have included rare reports of periorbital oedema occurring with the use of Hyason in conjunction with local anaesthetics in ophthalmology.

Severe allergic reactions including anaphylaxis have been reported rarely. Local irritation, infection, bleeding and bruising occur rarely.

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 the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.

No cases of overdose appear to have been reported.

Hyason is an enzyme that has a temporary and reversible depolymerising effect on the polysaccharide hyaluronic acid, which is present in the intercellular matrix of connective tissue.

Not applicable

There are no additional pre-clinical data of relevance to the prescriber.

Physical incompatibility has been reported with heparin and adrenaline, although in clinical practice very low concentrations of adrenaline are combined with Hyason without problems. Furosemide, the benzodiazepines and phenytoin have been found to be incompatible with Hyason.

The solution should be used immediately after preparation.

For single use only. Discard any unused contents.