Ganfyd:Pharmacological data limitations
Always refer to prescribing information relevant to your practice, in particular manufacturers and regulatory guidance. The pharmacological and other data given on GANFYD will have multiple limitations. Firstly it is potentially incomplete, or even inaccurate. It is possible by the nature of this media for accurate information to be altered and made inaccurate, at any time. Such alterations might be able to be identified in the history of the page. Please bring them to our attention. Authors and readers are encouraged to check against the British SPCs, the EMEA EPARs and the FDA CDER labels as these contain information that has been verified to the highest standard. The differences can be interesting in their own right. Members of the public should verify against the information that the manufacturer provides. Many of the original authors will have practised in a single country, presently predominantly the United Kingdom. They will have tended to select and present information relevant to their practice and changes in that practice. Indeed presented data will be biased towards that important in clinical practice or of general interest. Also when verifying this information, the original sources may not be readily available, and transcription errors increasingly become possible. Often authors will use readily available internet sources of information such as abstracts of published papers. Abstracts tend to emphasize positive results from subgroup analysis so may inadvertently introduce bias. Even where the original source was available an erratum may be overlooked. Authors contributing to this website discovered that readily available internet sources can disagree over decades as to when a medical disease was first described 500 years ago. Compromises also have to be made in presenting information. Such are commented on further here.
Names of Drugs
The rINN name is likely to be accurate, but the alternative names are almost certainly incomplete. Often drugs are formulated as a salt or chelate. Sometimes a particular salt or chelate will have different pharmacological properties or be licensed in different countries. Doctors often only specify the active component in generic prescriptions. Tradenames come and go, and can vary with formulation and country. The trade name first on the UK market will usually be given. Paracetamol is known as acetaminophen in the United States for historic reasons, and salbutamol is known as albuterol.
Again incomplete and should be verified. Adult doses will be given unless specified specifically. Out of licence or evidence base use of medicines is common. This may well be because the indication is rare and not worth the cost of a license application.
As out of license use of medications is common, the indications indicated in GANFYD are likely to reflect this. Indeed some drugs are licensed in one country for a given indication and never marketed in another for this indication although are commonly used. A drug like pantoprazole may well be used in the place of omeprazole even though the later has a larger evidence base in terms of individual research papers and number of licensed indications.
These may be simplified for presentation purposes. Indeed if a substance is normally presented as a complex hydrated magnesium salt, as is the case with esomeprazole it will not be presented as such on GANFYD.
Metabolism & Interactions
Only likely to be given if relevant to clinical use. The cytochromes used in metabolism of the drug may well be given here if relevant.
Mechanism of Action
Please check the drug class category, if no information.
These can be amazingly irrelevant, particularly for "prodrugs", where the drug taken is relatively or completely inactive, but converted to an active form in the body. For example omeprazole has quite a short half life but is actually converted into an achiral molecule inside the parietal cell that inhibits the proton pump for many hours.
These such as contra-indications, cautions and interactions and side effects are often incomplete on GANFYD. It is extremely difficult to present such data in total context due to problems with the evidence base, including its complexity, and the time needed to review it. There are many other sources of such information that will remain for some time better than GANFYD, but readers should always remember GANFYD has strengths with breaking news.