diphenhydramine
Regulatory sources consulted
Approved indications
- In adults and from age 6 years, local relief of allergic skin itching and stinging from insect bites, nettles, or jellyfish.
Contraindications
Absolute
- Hypersensitivity, simultaneous use of another diphenhydramine medicine, open wounds or infected skin, and children under 2 years.
Clinical warnings
- Major warning · It may cause photosensitivity or phototoxicity; avoid intense sunlight. Systemic absorption may cause sedation, anticholinergic effects, and mask symptoms of ototoxicity. — CIMA NEOSAYOMOL 20 mg/g crema, registro 61459
- Cutaneous hypersensitivity, photosensitivity or phototoxicity, contact dermatitis, pruritus, exanthematous rash, and erythema have been reported with unknown frequency; stop and seek advice if they occur. — CIMA NEOSAYOMOL 20 mg/g crema, registro 61459
Drug interactions
- ModerateOther photosensitizing medicines
Mechanism: It may enhance photosensitivity or phototoxicity reactions.
Recommendation: Avoid the combination or intensify photoprotection and skin monitoring.
https://cima.aemps.es/cima/dochtml/ft/61459/FT_61459.html
- ModerateAllergen skin tests
Mechanism: Diphenhydramine may interfere with the result.
Recommendation: Stop application at least 3 days before testing.
https://cima.aemps.es/cima/dochtml/ft/61459/FT_61459.html
- HighAlcohol and sedative medicines
Mechanism: If systemic absorption occurs, sedation and the hypnotic effects of alcohol, opioids, barbiturates, benzodiazepines, or antipsychotics may be enhanced.
Recommendation: Avoid alcohol and use heightened monitoring with sedatives, especially when applying over large areas or damaged skin.
https://cima.aemps.es/cima/dochtml/ft/61459/FT_61459.html
- HighAnticholinergic medicines
Mechanism: If systemic absorption occurs, diphenhydramine may enhance the anticholinergic effects of antiparkinson agents, tricyclic antidepressants, MAO inhibitors, neuroleptics, and other antimuscarinics.
Recommendation: Avoid combining with potent anticholinergics; if unavoidable, closely monitor for anticholinergic toxicity.
https://cima.aemps.es/cima/dochtml/ft/61459/FT_61459.html
- HighNarrow-therapeutic-index CYP2D6 substrates
Mechanism: If systemic absorption occurs, diphenhydramine may inhibit CYP2D6 and increase exposure to substrates such as metoprolol.
Recommendation: Monitor substrate response and toxicity; consider adjustment under clinical supervision.
https://cima.aemps.es/cima/dochtml/ft/61459/FT_61459.html
Pregnancy and lactation
Use during pregnancy or breastfeeding only if potential benefits outweigh risks and no safer alternatives are available.
Recent literature (PubMed)
Contrast media, including iodinated contrast media and gadolinium-based contrast agents, are commonly administered pharmaceuticals with excellent safety profiles. However, a minority of the population may experience a hypersensitivity reaction following intravenous administration. Hypersensitivity reactions can be immediate or delayed, and range from mild, such as urticaria, to severe, including anaphylaxis. There is emerging evidence that longstanding pretreatment protocols, such as diphenhydramine and corticosteroids, are ineffective and have the potential for side effects and other harms. Moreover, the evidence for efficacy on which this practice is based is weak and outdated. A joint collaborative working group of representatives from the Canadian Association of Radiologists and the Canadian Society of Allergy and Clinical Immunology was assembled to inform medical professionals and hospital policies regarding hypersensitivity reactions to contrast media. The objectives of the working group were to provide an overview of the epidemiology, physiology, risk factors, and types of hypersensitivity reactions; to synthesize the evidence for pretreatment strategies that minimize the risk of a breakthrough reaction for both iodinated contrast media and gadolinium-based contrast agents; to review the allergy investigations used to evaluate patients with a history of severe hypersensitivity reaction; and to provide an overview of existing guidelines. Following appraisal of the evidence, the working group established recommendations based on consensus in this practice guidance.
Restless legs syndrome (RLS) is a sleep-related movement disorder that affects approximately 3% of US adults to a clinically significant extent and can cause substantial sleep disturbance. Restless legs syndrome is characterized by an overwhelming urge to move the limbs, typically the legs, often accompanied by unpleasant limb sensations (eg, achiness, tingling). Symptoms, provoked by immobility, are relieved while moving and are typically present or most severe in the evening or at night. Restless legs syndrome symptoms may lead to difficulty falling asleep, staying asleep, or returning to sleep. According to population-based studies, approximately 8% of US adults experience RLS symptoms of any frequency annually and 3% experience moderately or severely distressing symptoms at least twice weekly. Patients with RLS have impaired quality of life and elevated rates of cardiovascular disease (29.6% with coronary artery disease, stroke, or heart failure), depression (30.4%), and suicidal ideation or self-harm (0.35 cases/1000 person-years). Restless legs syndrome is common among patients with multiple sclerosis (27.5%), end-stage kidney disease (24%), and iron deficiency anemia (23.9%); during pregnancy and especially in the third trimester (22%); with peripheral neuropathy (eg, diabetic, idiopathic; 21.5%); and with Parkinson disease (20%). Other risk factors include family history of RLS, northern European descent, female sex (2:1 vs male sex), and older age (RLS prevalence of 10% in adults ≥65 years). Restless legs syndrome is diagnosed based on clinical history; polysomnography is not recommended for diagnosis. Iron supplementation with ferrous sulfate (325-650 mg daily or every other day) or intravenous iron (1000 mg) should be initiated for serum ferritin level less than or equal to 100 ng/mL or transferrin saturation less than 20%. If possible, medications associated with RLS, including serotonergic antidepressants, dopamine antagonists, and centrally acting H1 a
Oral mucositis (OM) is a frequent complication in cancer patients who are undergoing chemotherapy or radiotherapy. It manifests as an inflammation of the oral mucosa, sometimes provoking severe consequences such as eating limitations, difficulty in speaking, and possibly superinfection. The aim of this review was to update the evidence published during the last five years on the treatment of oral mucositis induced by radiotherapy and/or chemotherapy in patients with cancer. A search was conducted in Pubmed, Scielo and Scopus, using the search terms mucositis, stomatitis, therapy, treatment, oral cancer, oral squamous cell carcinoma, head and neck cancer and head and neck carcinoma, with Mesh terms and free terms, from 2017 to January 2023. The systematic review was conducted in accordance with the PRISMA guidelines. A total 287 articles were retrieved, of which 86 were selected by title and abstract, and 18 were included after full-text analysis. The most frequently assessed variables were OM severity, pain intensity and healing time. Treatment types were diverse, and included drugs, mouthwashes, medicines based on plant extracts, cryotherapy and low-intensity laser therapies. Dentoxol mouthwashes, Plantago major extract, thyme honey extract, zinc oxide paste, vitamin B complex combined with GeneTime, and the consumption of L-glutamine are effective in diminishing the severity of OM. Pain intensity was lower with doxepin mouthwashes and diphenhydramine-lidocaine-antacid mouthwashes. La mucositis oral (MO) es una complicación frecuente en pacientes oncológicos sometidos a quimioterapia o radioterapia. Se manifiesta como una inflamación de la mucosa oral, provocando en ocasiones graves consecuencias como limitaciones en la alimentación, dificultad para hablar y posiblemente sobreinfección. Objetivo: El objetivo de esta revisión fue actualizar la evidencia publicada durante los últimos cinco años sobre el tratamiento de la mucositis oral inducida por radioterapia y/o q