Action and mechanism

- Topical anti-inflammatory and analgesic. Diclofenac is a non-steroidal anti-inflammatory drug derived from phenylacetic acid, which acts by preventing the synthesis of prostaglandins and other prostanoids, through the inhibition of cyclooxygenase involved in inflammatory processes.

Pharmacokinetics

Topical route:

- Absorption:
* Gel: Bioavailability of 6%. The Cmax is 15-53.8 ng/ml, reached after 10-14 h of application.

- Distribution: High binding to plasma proteins (99%), mainly to albumin. Vd of 1.3 l/kg.

- Metabolism: It is metabolized almost completely in the liver, through hydroxylation and glucuronic acid conjugation reactions.

- Elimination: It is eliminated in urine (65%) and bile (35%), primarily as conjugated metabolites. Small amounts of unchanged diclofenac are detected in urine and bile. The t1/2 is 2 h.

Instructions

- [PAIN]. Symptomatic treatment of acute inflammatory and/or painful processes, such as:
* [CONTUSION] or [SPRAIN] caused by twisting.
* [TORTICOLLIS] or other [CONTRACTURE].
* [LUMBALGIA].

Posology

- Diclofenac Kern Pharma, Diclokern, Voltadol and Voltadol Forte (adults and adolescents over 14 years): apply a thin layer (2-4 g of gel, equivalent to the size of a cherry or walnut, respectively), 3-4 times a day or 1 application every 12 hours (preferably morning and night) in the case of Voltadol Forte.

Guidelines for proper administration

It should be avoided when applied to areas of skin with dermatitis, open wounds, burns, or infections, and the area should not be covered with occlusive bandages, as this could promote greater systemic absorption of diclofenac.
It should be avoided when applied near the eyes, as well as on mucous membranes.
After application, hands should be washed unless they are the site of treatment.
If symptoms persist or worsen after 5 days of use, it is recommended to consult a doctor and/or pharmacist.




- Emulsion, gel: Apply to the area to be treated, massaging until the gel is absorbed. Wash your hands afterwards.

Contraindications

- Hypersensitivity to diclofenac or any other component of the medication. There are reports of cross-reactions between different NSAIDs, as well as with salicylates, therefore diclofenac is also not recommended in cases of [NSAID ALLERGY] or [SALICYLATE ALLERGY].

- [PEPTIC ULCER] active. Although topical application limits the absorption of diclofenac, its use is not recommended in patients with peptic ulcer due to the potential for ulcer aggravation.

Precautions

[PHOTOSENSITIVITY REACTIONS]. Diclofenac has caused photosensitivity reactions. It is recommended to avoid exposing treated areas to sunlight or UV light for at least one day.

- Systemic reactions. The risk of systemic reactions from topical diclofenac is minimal, although it cannot be ruled out if significant systemic absorption occurs, as may happen if it is applied to damaged skin (dermatitis, burns, wounds) or with an occlusive dressing. It is recommended to adhere to the dosage recommendations in patients with asthma, a history of peptic ulcer, renal or cardiac insufficiency, as well as hypertension.

Warnings about excipients:

- Because it contains butylhydroxytoluene as an excipient, it may produce local skin reactions, such as contact dermatitis, or irritation of the eyes or mucous membranes.

Warnings about excipients:

- This medicine contains propylene glycol, so it may cause skin irritation.

Advice to the patient

- You should consult your doctor and/or pharmacist if you have had previous allergic reactions to other anti-inflammatory drugs, including acetylsalicylic acid.

- Do not cover the area with occlusive bandages.

- Do not apply to areas of skin with burns, open wounds, dermatitis or infections.

- Do not expose treated areas to sunlight or UVA light sources until at least one day after the last application.

- If symptoms persist or worsen after 3 days of use, consult your doctor and/or pharmacist.

- Apply to the skin, massaging until the gel is absorbed.

Interactions

No interactions have been described at the recommended doses. However, in case of significant systemic absorption, the same interactions as with systemic diclofenac could occur.
Furthermore, as with any topical treatment, it is not advisable to apply two topical medications at the same time to the same area.

Pregnancy

- FDA Pregnancy Category C(D). Category C during the first 30 weeks of pregnancy and Category D from week 30 of pregnancy onward. Approximately 10% of the topical dose is absorbed systemically, with considerably lower bioavailability via the topical route compared to the oral route. Adequate and well-controlled studies in humans with topical diclofenac are not available, but systemic diclofenac has resulted in fetal toxicity in late pregnancy. Although cutaneous absorption is minimal, the possibility of systemic effects cannot be ruled out.
Topical use of diclofenac during the first two trimesters of pregnancy is only acceptable if, in the absence of other safer therapeutic alternatives, the benefits outweigh the possible risks.
The use of diclofenac during the third trimester of pregnancy is contraindicated, as diclofenac has been associated with delayed labor and adverse cardiovascular effects in the fetus, such as premature closure of the ductus arteriosus and pulmonary hypertension, and renal effects, such as acute renal failure and oligohydramnios. It may also increase bleeding time in the mother.

Lactation

It is unknown whether topical diclofenac is excreted in breast milk, and the potential consequences for the infant. Approximately 10% of a topically applied dose is absorbed systemically. Systemic diclofenac is excreted in small amounts in breast milk. Some experts accept the use of topical diclofenac during breastfeeding. Manufacturers advise discontinuing breastfeeding or avoiding its use.

Children

See Dosage.

Seniors

The elderly may be especially susceptible to adverse reactions from diclofenac, so it is recommended to use it with caution.

Adverse reactions

- Dermatological: Frequent (1-10%) local reactions in the application area, such as [PRURITUS], [SKIN IRRITATION], [ERYTHEMA], [EXANTHEMATOUS ERUPTIONS], with the appearance of pustules or papules on occasion.

- Allergic: Infrequent (0.1-1.0%) [HYPERSENSITIVITY REACTIONS], [CONTACT DERMATITIS]; isolated cases of [ANAPHYLAXIS], [ANGIOEDEMA] and [PHOTOSENSITIVITY REACTIONS].
In case of significant absorption, systemic adverse reactions of diclofenac may occur.

Overdose

Symptoms: Due to its route of administration, symptoms are not very likely to appear in case of overdose, although accidental ingestion or improper application could produce the typical systemic adverse effects.
Treatment: In case of accidental ingestion, gastric lavage and symptomatic treatment will be performed.