About the Litt database

This unique website allows you to search the profiles of generic and trade name FDA-approved drugs, biological products and biosimilars. It also includes a selection of vaccines, herbal remedies, supplements and other substances used in medical procedures, such as toxins and fillers. The Litt database provides peer-reviewed reports and reviews of adverse drug reactions, and these are all linked directly to PubMed. The Litt database is updated on a continuous basis with the latest developments in the field, including additional new drugs and new references, so that our subscribers can stay abreast of the rapid advances in medical therapy and have rapid access to potentially vital safety data for their patients.

There are various search options to ensure you get to the information you want as quickly as possible:

  • Drugs
  • Adverse reaction (Notes 1 to 4)
  • Drug class
  • Herbal
  • Reaction category
  • Company
  • Indications

Each drug profile will provide you with a wealth of essential information, including:

  • Synonyms
  • Trade names
  • Pharmaceutical company/companies
  • Class of drug
  • Indications
  • Half-life
  • Drug-drug interactions (Note 5)
  • Contraceptive, reproductive and pregnancy advice associated with use of a drug (Note 6)
  • Any adverse reactions attributed to the class of drug
  • Any clinical note on use
  • Any “Black box” warning required by the FDA
  • Adverse drug reactions, with a colored box for incidence (where reported) and a colored flag for its severity (Note 7)
  • Adverse drug reactions associated with identifiable genetic polymorphisms (pharmacogenetic markers)

Adverse drug reactions are categorized first by dermatological and related manifestations – skin, hair, nails, mucosal – then under these categories (in alphabetical order): cardiovascular, central nervous system, endocrine/metabolic, gastrointestinal, genitourinary, hematologic, local, multi-organ and/or multi-metabolic adverse reactions, neuromuscular/skeletal, ocular, otic, renal, respiratory – and finally ‘other’ (for those adverse drug reactions which are not readily classifiable under the previous categories).

There are links to drug reviews, where available; to compare each drug’s reaction profile with that of up to three others; to explore the Indication (with photographs of the adverse reaction, if available) and any other drugs that may cause it; to save a search for later retrieval; and to watch a drug and receive a weekly email alert of additions to the drug profile.

Pediatric patients are defined as those up to 18 and geriatric patients as those over 75 years of age.

The Litt database was originated by Jerome Z. Litt from his annual Drug Eruptions and Reactions Manuals; it is now edited by Neil H. Shear.


  1. Adverse drug reactions: The following definition is used for an adverse drug reaction in the Litt database: “An appreciably harmful or unpleasant reaction, resulting from an intervention related to the use of a medicinal product, which predicts hazard from future administration and warrants prevention or specific treatment, or alteration of the dosage regimen, or withdrawal of the product”. Adverse drug reactions are distinguishable from adverse events. An adverse event is any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medical treatment or procedure that may or may not be considered related to the medical treatment or procedure. The terms ‘adverse reaction’ and ‘adverse effect’ are regarded as interchangeable, but these two terms are not synonymous with the ‘side effect’ (of a drug). A side effect is any effect caused by a drug other than the intended therapeutic effect, whether beneficial, neutral or harmful.

    The quality of the literature on adverse drug reactions is heterogeneous, and there is the potential for confusing adverse drug reactions with adverse events, the symptoms of a complex disease being treated with a drug or the common background symptoms found in a normal and untreated population.

    • R. Edwards and J. K. Aronson, ‘Adverse drug reactions: definitions, diagnosis, and management’, Lancet, 2000, 356, 1255-1259.
    • J. R. Nebeker, P. Barach and M. H. Samore, ‘Clarifying adverse drug events: a clinician’s guide to terminology, documentation, and reporting’, Annals of Internal Medicine, 2004,140, 795-801.
    • K. Tan, K. J. Petrie, K. Faasse, M. J. Bolland and A. Grey, ‘Unhelpful information about adverse drug reactions’, British Medical Journal, 2014, 349, g5019; doi: https://doi.org/10.1136/bmj.g5019
    • Common Terminology Criteria for Adverse Events (CTCAE) v5.0, 2017 (Common Terminology Criteria for Adverse Events (CTCAE) (cancer.gov)).
  2. Adverse drug reaction terminology: In order to avoid a multiplicity of terms in the Litt database, some related adverse reactions are combined, e.g. ‘Neuropsychiatric / neuropsychological adverse effect’; ‘Nephrotoxicity / kidney injury / acute kidney injury (AKI) / drug-induced kidney injury’. Some authors will use a trivial name for an adverse reaction, others the orthodox medical term. These alternative names are identified where appropriate, e.g. ‘Borborygmus (bowel sounds)’; ‘Eructation (belching)’; ‘Dipsia (thirst)’. Names of adverse drug reactions in the Litt database are extracted from the original medical and scientific literature and may not always coincide with names in the Common Terminology Criteria for Adverse Events (CTCAE) v5.0, 2017 (Common Terminology Criteria for Adverse Events (CTCAE) (cancer.gov)).
  3. Complex adverse drug reactions: Categorizing complex adverse drug reaction can be problematical. If a cutaneous effect is one of the manifestations of a complex reaction, then it is listed under ‘Skin’, e.g. ‘Thrombotic thrombocytopenic purpura’. Otherwise, these complex reactions are generally shown under the category ‘Other’, e.g. ‘Vogt-Koyanagi-Harada syndrome’. To aid their identification and location in the Litt database, complex adverse drug reactions are additionally listed in a separate Reaction Category, ‘Multi-Organ and/or Multi-Metabolic Adverse Reactions’, and are hyperlinked to their current location in the Litt database (https://www.drugeruptiondata.com/multi-organ).
  4. Combinations of drugs: Many drugs are administered in combinations. In the Litt database, adverse reactions for the majority of drug combinations are listed for each component of that combination irrespective that only one drug in the combination may be responsible for the observed adverse drug reaction. For example, the adverse reactions of FOLFOX are listed under the individual drugs of that combination, fluorouracil, leucovorin and oxaliplatin. For a few well-established drug combinations, the adverse reactions are recorded for the combination, e.g. Co-trimoxazole, which is a combination of sulfamethoxazole and trimethoprim.
  5. Drug-drug interactions: Details of drug-drug interactions in the Litt database are abstracted from the Labels for FDA-Approved Drugs (https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm). For a comprehensive account of drug-drug interactions, please refer to Stockley's Drug Interactions: A source book of interactions, their mechanisms, clinical importance and management, edited by Claire L. Preston, 12th edition, Pharmaceutical Press, London, 2019; ISBN 978 0 85711 347 4, also available online.
  6. Contraceptive, reproductive, pregnancy and lactation advice associated with use of a drug: Labels for FDA-Approved Drugs (https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm) are the main source of information for contraceptive, reproductive, pregnancy and lactation advice in the Litt database. The former FDA-assigned pregnancy categories, A to D and category X, which were phased out from 2015 onwards, are explained under the ‘Help’ tab: (https://www.drugeruptiondata.com/search_help).
  7. Severity of adverse drug reactions: The Common Terminology Criteria for Adverse Events (CTCAE) was developed by the National Cancer Institute (NCI) Cancer Therapy Evaluation Program to be a worldwide standard for defining and grading adverse events (AEs) experienced by patients enrolled in oncology clinical drug trials. CTCAE grades are based on the potential impact the AE has on clinical management, activities of daily living, dose modifications, or medication discontinuation. Clinical descriptions for the severity of an adverse event / adverse drug reaction are assigned to five grades – Grades 1 to 5 – in the latest version of CTCAE (version 5.0, 2017; available online as a pdf):
    • Grade 1: Mild; asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated.
    • Grade 2: Moderate; minimal, local or non-invasive intervention indicated; limiting age-appropriate instrumental ‘activities of daily living’ (ADL).
    • Grade 3: Severe or medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; limiting self-care ADL.
    • Grade 4: Life-threatening consequences; urgent intervention indicated.
    • Grade 5: Death related to adverse event / adverse drug reaction.
  8. In the Litt database, Grades 3 to 5 are identified for adverse drug reactions if this information is available, and are signified by a colored flag.

    •       Grade 3 – Hospitalization possible
    •       Grade 4 – Life threatening
    •       Grade 5 – Fatal

    Adverse drug reactions may also be qualified by the descriptors ‘serious’ and ‘severe’. These two terms are used interchangeably in the primary and abstracted medical literature, and as a consequence both these terms are quoted in the Litt database. However, the World Health Organisation (WHO) does distinguish between ‘serious’ and ‘severe’ for describing adverse events and reactions.

    The WHO defines a serious adverse event or reaction as any untoward medical occurrence that at any dose:

    • results in death;
    • requires inpatient hospitalization or prolongation of existing hospitalization;
    • results in persistent or significant disability or incapacity;
    • is life-threatening;
    • results in a congenital anomaly or birth defect.


    Further, the WHO notes that to ensure there is no confusion or misunderstanding of the difference between the terms ‘serious’ and ‘severe’, the following clarification is provided: The term ‘severe’ is not synonymous with ‘serious’. In the English language, ‘severe’ is used to describe the intensity (severity) of a specific event (as in mild, moderate or severe); the event itself, however, may be of relatively minor medical significance (such as severe headache). Seriousness (not severity), which is based on patient/event outcome or action criteria, serves as guide for defining regulatory reporting obligations.

    References (available online as pdfs)
    World Health Organisation, Safety of Medicines: A guide to detecting and reporting adverse drug reactions, 2002, p 6.
    World Health Organisation, Safety monitoring of medical products: reporting system for the general public, 2012, p 19.

    Further explanations of the Litt database may be found under the ‘Help’ tab: (https://www.drugeruptiondata.com/search_help).

    Comments on all aspects of the Litt database, and in particular the terminology and classification of adverse drug reactions, are welcomed by the Editor.