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 produces a decrease in dermal itching.PATIENT ADVICEPATIENT ADVICE:- Protect the application area from sunlight to avoid photosensitivity reactions.- Assessment by the 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 a 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 shown hypersensitivity to any compound in this group.PREGNANCY- It is unknown whether diphenhydramine can be absorbed topically. No adequate and well-controlled studies have been conducted in humans, so the use of this medicine is only accepted 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 nor is there any specific data on its pharmacokinetics. INDICATIONS - Symptomatic relief of [ITCHING] of the skin due to [INSECT BITES], contact with jellyfish or nettles, etc. INTERACTIONS - May potentiate the photosensitizing effects of other active ingredients that give rise to photosensitivity reactions. BREASTFEEDING - 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 infant known. CHILDREN - The use of diphenhydramine is not recommended in children under six years of age, especially newborns and infants. RULES FOR CORRECT ADMINISTRATION - Thoroughly clean the affected area, allow to dry, and gently spread a small amount of cream onto the affected area of skin. Wash your hands after application.DOSAGEDOSAGE:- Topical route: Adults and children over 6 years; 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 to eroded, bleeding skin, with [BLISTERS], [WOUNDS] or exudates, as percutaneous absorption may occur, producing systemic effects.- Diphenhydramine may cause [PHOTOSENSITIVITY REACTIONS], so it is recommended not to sunbathe during treatment and to protect yourself with sunscreen.- [PORPHYRIA]. H1 antihistamines have been associated with the appearance of porphyritic outbreaks, so they are not considered safe in these patients. PRECAUTIONS RELATED 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 appear after topical administration. [PHOTOSENSITIVITY REACTIONS] may also occur after intense exposure to sunlight, with [CONTACT DERMATITIS], [PRURITUS], [EXANTHEMA], and [ERYTHEMA]. OVERDOSE - Symptoms: Accidental ingestion or excessive topical absorption through the skin may produce signs related to the toxicity of diphenhydramine. These include sedation, drowsiness, and anticholinergic symptoms. At high doses, coma, ataxia, increased muscle reflexes, and seizures may occur. - Treatment: The product should be rapidly evacuated by stomach 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 - BUTYL HYDROXYANISOLE (E-320) HYDROCHLORIDE (EXCIPIENT): 0