Post-menstrual age: The term post-menstrual age, as used in this book, refers to the child’s total age in weeks from the start of the mother’s last menstrual period (LMP). Thus a 7-week old baby born at 25 weeks’ gestation is treated as having a post-menstrual age of 32 weeks.

The term ‘post-conceptional age’ is sometimes incorrectly used to describe this combination, although technically, conception occurs about 2 weeks after the start of the LMP. The term ‘post-conceptional age’ is best avoided. Where the date of conception is determined during assisted reproductive techniques, the convention for calculating gestation at birth is to add 2 weeks to the ‘conceptual age’.

Giving intravenous drugs: Intravenous (IV) drugs should always be given slowly, with a few notable exceptions. This universal good practice is not reiterated in each drug monograph. A simple way of achieving slow administration is described in p. 8. Where previous dilution or a particularly slow rate of infusion is important, this is specified in the relevant drug monograph, and the reason given. Drugs should also be given separately. Where two different IV drugs have to be given at the same time, the best way to stop them mixing is described in p. 22. Intramuscular (IM) drugs should never be mixed, except as described in the individual drug monographs.

Continuous co-infusion: Special problems arise when it is necessary to give more than one drug continuously and vascular access is limited. Here terminal co-infusion (the mixing of two different infusates using a tap or Y connector sited as close to the patient as possible) is sometimes known to be safe. In the most frequently encountered situations where such co-infusion is safe, a comment to that effect occurs in the relevant drug monograph. In all other situations two different infusion sites should be used unless advice to the contrary has been obtained from the local hospital pharmacy. Advice relating to Parenteral Nutrition (TPN) only applies to formulations similar to the one described in this compendium.

Drug names: Drugs are, in general, referred to by their non-proprietary (‘generic’) name, following the usage currently adopted by the BNF. Where, for clarity, a proprietary name has been used, the symbol ® has been appended the first time it is used. Where the British Approved Name (BAN) or the United States Adopted Name (USAN) differ from the recommended International Non-proprietary Name (rINN), these alternatives are also given. All synonyms are indexed.

Symbols and abbreviations: Cross references between monographs are marked by the Latin phrase quod vide (contracted to q.v.). Drugs vary in the extent to which they are distributed within the body. Some only accumulate in the extracellular tissues. Others are taken up and concentrated in some or all body tissues, the total amount in the body being more than would be presumed from a measure of that present in the blood. This is referred to as the drug’s apparent volume of distribution – summarised by the symbol V_D. References to a randomised controlled trial are marked by the symbol [RCT]; those referring to a systematic review or meta-analysis are marked [SR]. Drugs for which the Cochrane Collaboration has produced a systematic review are marked with , and vaccines for which one can access official UK guidance via this book’s website are marked with . Other abbreviations have been kept to a minimum and are explained in the index.