Diclofenac

INSTRUCTIONS FOR MEDICAL USE OF THE MEDICINAL PRODUCT DICLOFENAC (DICLOFENAC)

Composition:

Active substance: 1 g of gel contains sodium diclofenac – 10 mg;

Excipients: methylparahydroxybenzoate (E 218), propylparahydroxybenzoate (E 216), ethanol 96%, glycerol, mineral oil, carbomer, polyethylene glycol hydrogenated castor oil, 15% ammonia solution, purified water.

Pharmaceutical form. Gel.

Main physicochemical properties: white or slightly yellowish-white homogeneous gel.

Pharmacotherapeutic group.

Topical agents used for joint and muscular pain. Topical non-steroidal anti-inflammatory agents. Diclofenac.

ATC code M02A A15.

Pharmacological Properties

Pharmacodynamics

Diclofenac is a nonsteroidal anti-inflammatory agent with pronounced anti-rheumatic, analgesic, anti-inflammatory, and antipyretic effects. Its main mechanism of action is the inhibition of prostaglandin biosynthesis.

In inflammation caused by injuries or rheumatic diseases, Diclofenac helps reduce pain, tissue swelling, and shortens the recovery period of functions in injured joints, ligaments, tendons, and muscles. It has been demonstrated that Diclofenac reduces acute pain within 1 hour after the initial application. 94% of patients responded to Diclofenac within 2 days of treatment, compared to 8% responding to placebo. Relief of pain and functional impairments was achieved after 4 days of treatment with Diclofenac. Due to its water-alcohol base, the medicinal product also has a local anesthetic and cooling effect.

Pharmacokinetics

The amount of diclofenac absorbed through the skin is proportional to the application area and depends on both the total applied dose of the drug and the degree of skin hydration. After topical application of 2.5 g of Diclofenac to a skin surface area of 500 cm², the extent of diclofenac absorption is approximately 6%. Application of an occlusive dressing for 10 hours results in a threefold increase in diclofenac absorption.

After application of Diclofenac to the skin over wrist and knee joints, diclofenac is detected in blood plasma (where its maximum concentration is approximately 100 times lower than after oral administration), in the synovial membrane, and in synovial fluid. The binding of diclofenac to blood proteins is 99.7%.

Diclofenac accumulates in the skin, which acts as a reservoir, allowing gradual release of the substance into adjacent tissues. From there, diclofenac primarily penetrates into deeper inflamed tissues, such as joints, where it continues to act and is found at concentrations nearly 20 times higher than in blood plasma.

Diclofenac is predominantly metabolized via hydroxylation, forming several phenolic derivatives, two of which are pharmacologically active, although to a much lesser extent than diclofenac.

Diclofenac and its metabolites are primarily excreted in urine. The total systemic plasma clearance of diclofenac is 263 ± 56 ml/min, and the terminal half-life is on average 1–3 hours.

In renal or hepatic insufficiency, the metabolism and elimination of diclofenac are not altered.

Clinical characteristics.

Indications.

Local treatment of pain and inflammation of joints, muscles, ligaments, and tendons of rheumatic or traumatic origin.

Contraindications.

Hypersensitivity to diclofenac or to other components of the medicinal product. History of asthma attacks, urticaria, or acute rhinitis induced by acetylsalicylic acid or other nonsteroidal anti-inflammatory drugs. The last trimester of pregnancy.

Special precautions.

Use with caution concomitantly with oral nonsteroidal anti-inflammatory drugs.

The likelihood of developing systemic adverse effects with topical application of diclofenac is minimal compared to oral forms, but it cannot be completely ruled out when the drug is applied over relatively large skin areas for prolonged periods.

Diclofenac should be applied only to intact skin areas, avoiding application on inflamed, damaged, or infected skin. Contact with eyes and mucous membranes should be avoided. The gel must not be swallowed.

The product may cause skin reactions and allergic reactions (possibly delayed).

If any skin rash appears, treatment should be discontinued. Diclofenac should not be used under occlusive, air-impermeable dressings, but application under non-occlusive dressings is permitted. In case of ligament sprains, the affected area may be bandaged.

Interaction with other medicinal products and other types of interactions.

Since systemic absorption of diclofenac after topical application is very low, the probability of interactions is very small.

Special precautions for use.

Use during pregnancy or breastfeeding.

Clinical experience with use in pregnant women is limited; therefore, this medication is not recommended during pregnancy or breastfeeding. Diclofenac is contraindicated during the third trimester of pregnancy due to the potential risk of uterine inertia and/or premature closure of the ductus arteriosus.

Animal studies have not shown any evidence of harmful effects of the drug on pregnancy or embryonal development, parturition, or postnatal development. If there are strong medical reasons for using diclofenac during breastfeeding, when, in the physician’s opinion, the expected benefit outweighs the potential risk, the gel should not be applied to the mammary glands or to large areas of skin, and the duration of treatment should be minimized.

Data on the effect of topically applied diclofenac on human fertility are lacking.

Ability to influence reaction rate while driving or operating machinery.

No effect.

Method of administration and dosage.

For adults and children aged 14 years and older, apply diclofenac 3–4 times daily, gently rubbing it into the skin at the site of pain localization. The amount of gel applied depends on the size of the affected area (2–4 g, corresponding in size to a cherry or walnut, is sufficient for application to an area of 400–800 cm²).

After applying the medication, hands should be washed unless the hands themselves are the area being treated.

The duration of therapy depends on the nature of the disease and the treatment response.

The medication should not be used for longer than 14 consecutive days.

If symptoms have not resolved after 7 days, consult a physician.

Children.

Diclofenac is not recommended for use in children under 14 years of age. If the medication is used in children aged 14 years and older for longer than 7 days, or if symptoms worsen, medical advice should be sought.

Overdose.

Overdose is unlikely due to the low systemic absorption of diclofenac following topical application. However, in case of accidental ingestion, note that one 40 g tube of the medication contains the equivalent of 0.4 g of sodium diclofenac, which may lead to the development of systemic adverse reactions.

In case of accidental ingestion of the gel, the stomach should be emptied immediately and an adsorbent administered. Symptomatic treatment should be provided, employing therapeutic measures appropriate for poisoning with nonsteroidal anti-inflammatory drugs.

Side effects.

Unwanted reactions include mild transient skin reactions at the application site. Allergic reactions may rarely occur.

Infections and infestations

Rare (<1/10,000): pustular rashes.

Immune system disorders

Rare (<1/10,000): hypersensitivity reactions (including urticaria), angioneurotic edema.

Respiratory system disorders

Rare (<1/10,000): bronchial asthma.

Skin and subcutaneous tissue disorders

Common (≥1/100; <1/10): rash, pruritus, eczema, erythema, dermatitis, including contact dermatitis.

Uncommon (≥1/10,000; <1/1,000): bullous dermatitis.

Rare (<1/10,000): photosensitivity reactions, skin burning sensation.

Swelling.

Nervous system disorders: headache.

Gastrointestinal disorders: nausea.

Shelf life. 2 years.

Do not use after the expiry date stated on the packaging.

Storage conditions.

Keep out of reach of children.

Store in the original packaging at a temperature not exceeding 25 °C.

Packaging.

40 g of gel in a tube № 1; in a cardboard box.

Supply category.

Over-the-counter.

Manufacturer.

PJSC "CHIMFARMZAVOD "CHERVONA ZIRKA".

Manufacturer's address and location of business activity.

1, Gordienkovska Street, Kharkiv, Kharkiv Oblast, 61010, Ukraine.