Ranitidine-induced photosensitivity

Drug-Induced Photosensitivity-An Update: Culprit Drugs, Prevention and Management

Photosensitive drug eruptions are cutaneous adverse events due to exposure to a medication and either ultraviolet or visible radiation. In this review, the diagnosis, prevention and management of drug-induced photosensitivity is discussed. Diagnosis is based largely on the history of drug intake and the appearance of the eruption primarily affecting sun-exposed areas of the skin. This diagnosis can also be aided by tools such as phototesting, photopatch testing and rechallenge testing. The mainstay of management is prevention, including informing patients of the possibility of increased photosensitivity as well as the use of appropriate sun protective measures. Once a photosensitivity reaction has occurred, it may be necessary to discontinue the culprit medication and treat the reaction with corticosteroids. For certain medications, long-term surveillance may be indicated because of a higher risk of developing melanoma or squamous cell carcinoma at sites of earlier photosensitivity reactions. A large number of medications have been implicated as causes of photosensitivity, many with convincing clinical and scientific supporting evidence. We review the medical literature regarding the evidence for the culpability of each drug, including the results of phototesting, photopatch testing and rechallenge testing. Amiodarone, chlorpromazine, doxycycline, hydrochlorothiazide, nalidixic acid, naproxen, piroxicam, tetracycline, thioridazine, vemurafenib and voriconazole are among the most consistently implicated and warrant the most precaution by both the physician and patient.

Hypersensitivity reaction to ranitidine: description of a case and review of the literature

Ranitidine is an H2-receptor antagonist which is usually well tolerated. Hypersensitivity reactions to ranitidine, as well as other H2 antihistamines, have been rarely described. We report the case of a 47-year-old woman who developed an anaphylactic reaction to ranitidine used as intravenous premedication before anesthesia induction. The patient's history revealed that previous use of oral ranitidine for a peptic ulcer disease did not cause any adverse reaction. Intradermal test with ranitidine at a dilution of 1:100 gave an intense positive reaction. The protective role of H2-receptor antagonists as premedication is still unclear and should be carefully reconsidered on the basis of the available controversial evidence and the possible risk of hypersensitivity reactions.

Drug-induced photoallergic and phototoxic reactions

Drug-induced photosensitivity involves reactions to medication triggered by exposure of the skin to ultraviolet light. Medications that trigger reactions can be topical or oral. Following interaction of ultraviolet radiation with a chemical present in sufficient amounts in the skin, one of the several reactions may occur in susceptible patients, most commonly photoallergy or phototoxicity. These reactions can be diagnosed separately based on pathogenesis, clinical characteristics and histopathology. Phototoxic disorders have a higher incidence than photoallergic disorders. The action spectra for most photoallergens and phototoxins lie in the ultraviolet A range. Subtypes of drug-induced photosensitivity include dyschromia, pseudoporphyria, photo onycholysis, and lichenoid and telangiectatic reactions.