ACTION AND MECHANISM

- [ANTIALLERGIC], [HISTAMINERGIC ANTAGONIST (H-1)]. Diphenhydramine is an ethanolamine derivative that competitively, reversibly, and nonspecifically blocks H1 receptors, decreasing the systemic effects of histamine. It causes vasoconstriction and decreased vascular permeability, reducing the redness and edema associated with allergies. It partially mitigates symptoms associated with allergic processes such as eye redness or nasal congestion. It also reduces skin itching.

PATIENT ADVICE

PATIENT ADVICE:- Protect the application area from sunlight to avoid photosensitivity reactions.- Consult your pediatrician regarding the use of diphenhydramine in children under 6 years of age.- If symptoms persist for more than 7 days or worsen, discontinue treatment and consult your doctor.- For external use only on the skin. Do not use on large areas to avoid systemic absorption.- Avoid contact with eyes and mucous membranes.

CONTRAINDICATIONS

- Hypersensitivity to any component of the medication. Cross-reactions with other antihistamines may occur, so the use of any H1 antihistamine is not recommended in patients who have previously experienced hypersensitivity to any component of this group.

PREGNANCY

- It is unknown whether diphenhydramine can be absorbed topically. Adequate and well-controlled studies in humans have not been conducted, so its use is only acceptable if the potential benefits outweigh the possible risks and as long as there are no safer therapeutic alternatives.

PHARMACOKINETICS

- Topical route: At the recommended dose, only a very small amount of the active ingredients will be absorbed. The percutaneous absorption of diphenhydramine has not been quantified, and there are no specific data on its pharmacokinetics.

INDICATIONS

- Symptomatic relief of [ITCHING] of the skin due to [INSECT BITES], contact with jellyfish or nettles, etc.

INTERACTIONS

- It could enhance the photosensitizing effects of other active ingredients that lead to photosensitivity reactions.

LACTATION

- It is not known whether topical diphenhydramine is absorbed in sufficient quantities to be excreted in breast milk, nor are its possible adverse effects on the nursing infant known.

CHILDREN

- Diphenhydramine is not recommended for use in children under six years of age, especially newborns and infants.

RULES FOR CORRECT ADMINISTRATION

- Thoroughly clean the affected area, let it dry, and gently spread a small amount of cream over the affected area. Wash your hands after application.

POSOLOGY

DOSAGE: Topical use: Adults and children over 6 years of age: Apply a small amount to the affected area up to a maximum of 3-4 times a day. If symptoms persist for more than 7 days or worsen, discontinue treatment and consult a doctor.

PRECAUTIONS

- Avoid application on eroded, bleeding skin, with [BLISTERS], [WOUNDS] or exudates, since percutaneous absorption could occur producing systemic effects.- Diphenhydramine could cause [PHOTOSENSITIVITY REACTIONS], so it is recommended not to sunbathe during treatment, and to protect yourself with sunscreens.- [PORPHYRIA]. H1 antihistamines have been associated with the appearance of porphyric outbreaks, so they are not considered safe in these patients.

PRECAUTIONS RELATING TO EXCIPIENTS

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

ADVERSE REACTIONS

The side effects of diphenhydramine are usually mild and transient, being more frequent during the first days of treatment. There is great interindividual variability with respect to the frequency and intensity of symptoms, affecting mainly young children and the elderly. The most common adverse reactions are:* Allergic/dermatological. [HYPERSENSITIVITY REACTIONS] may rarely occur after topical administration. [PHOTOSENSITIVITY REACTIONS] may also occur after intense exposure to sunlight, with [CONTACT DERMATITIS], [PRURITUS], [EXANTHEMA RASHES] and [ERYTHEMA].

OVERDOSE

- Symptoms: Accidental ingestion or excessive topical absorption through the skin may produce signs related to diphenhydramine toxicity. These include sedation, drowsiness, and anticholinergic symptoms. At high doses, coma, ataxia, increased muscle reflexes, and seizures may occur. - Treatment: The product should be eliminated rapidly by gastric lavage or aspiration, or by inducing vomiting. In cases of acute poisoning, activated charcoal should be used. Seizures can be controlled with diazepam.

COMPOSITION

Diphenhydramine (topical): 20 milligrams - hydrochloride
BUTYL HYDROXYANISOL (E-320) (EXCIPIENT): 0