Fundamentals of Midwifery: A Textbook for Students (139 page)

Further reading activity

For further information access the following

[available online] http://www.medicines.org.uk/emc/.

[available online] http://www.nmc-uk.org/Publications/Standards/.

[available online] http://www.mhra.gov.uk/index.htm#page=DynamicListMedicines.

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There are rules around what medicines student midwives can administer; all students should make sure that they are familiar with these. The NMC and MHRA give out information about this, which is available via their websites. Currently ‘

’ (NMC 2011; MRHA 2013). The medicines contained on the midwives exemption list are identified by the NMC (2011) and MRHA (2013). Student midwives may also administer medicines if they are prescribed by a doctor; however, students must always be under the direct supervision of a sign-off midwife or nurse. There may be specific medicines that hospital Trusts do not allow stu- dents to administer so it is important that all students and qualified practitioners are aware of their drug policies. If there is any doubt about the role of students in the administration of medi- cines then students must discuss this with the mentor and refer to the Trust guidelines for the placement area.

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When a medicine is licensed it means it holds a marketing authorisation. It is licensed for a particular indication(s), route, age of patient and direction. However, medicines can be pre- scribed and used off label. The use of medicines outside the terms of the license (i.e., ‘off-label’) may be judged by the prescriber to be in the best interest of the patient on the basis of avail- able evidence. Such practice is particularly common in certain areas of medicine: for instance, in paediatrics where difficulties in the development of age-appropriate formulations means that many medicines used in children are used ‘off-label’ (MHRA 2009).

Unlicensed is when a medicine does not hold a marketing authorisation in this country and therefore needs to be made or imported. This should only be prescribed if the clinical need of the patient cannot be met by a licensed product or off label use. An example of unli- censed is the prescribing of two drugs for use in one syringe driver, or the prescribing of total parenteral nutrition; both of these are examples of acceptable clinical practice and recognised nationally.

Ensuring the right medicine is given to the right patient at the right time is key to ensuring safe

and effective practice. However, once you have administered the medication what is it actually doing for the patient? (A more in-depth analysis of pharmacology, cell structure and targets for medicines can be found in general pharmacology textbooks and are referenced at the end of this chapter.)

Pharmacology is concerned with scientific principles which can be applied to how the body interacts with medicinal compounds (medicines) and drugs in general. As healthcare practition- ers who will administer medicines, we need to know the affect that that particular medication will have in the body and also what the body (a living system) will do with that foreign substance.

Throughout this chapter, ‘medicines’ will be referred to when discussing a licensed medicinal compound rather than drugs. Drugs are chemical substances which interact with biological systems. Pharmacologists will be interested in drugs which will never be licensed medicines for human use. Further information can be obtained from the British Pharmacology Society [avail- able online] http://www.bps.ac.uk/

Two important principles in pharmacology are:

pharmacodynamics

pharmacokinetics.

Pharmacodynamics is usually referred to as‘what the drug does to the body’. When we admin- ister a medicine we expect there to be an effect. For example, if we have a headache and take an analgesic there is an expectation it will help the pain.

Pharmacokinetics is usually referred to as ‘what the body does to the drug’. When we admin- ister a medicine for example orally, this medicine must first be absorbed into the blood stream; it must then be distributed around the body, to the site of action to give the desired effect ‘Pharmacodynamic’; the medicine will often be metabolised (chemically changed) and then excreted or eliminated out of the body.

Medication for oral administration in the form of tablets and liquid.

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These four principles are:

absorption

distribution

metabolism

elimination.

Prescribers will make evidence-based decisions of which treatment (often a medication) a patient receives. Clinical decision-making is discussed elsewhere, but prescribers can also make decisions about which route of administration is used. The most commonly encountered route is oral (enteral) with liquid medicines, tablets and capsules (see Figure 15.1). In midwifery, intra- venous (IV) is used (into the vein, this allows for quick administration and usually a rapid effect). The IV route can be dangerous and fatalities have occurred. Other routes of administration in midwifery are identified in Table 15.1.

When a medicine is administered orally to a patient it is absorbed into the blood. The absorption of a medicine is dependent on the route of administration. Unless a medicine is given by the intravenous route, it will have to pass through membranes. A medicine given directly into the vein naturally reaches the blood stream immediately and has an effect sooner than oral.

When a medicine is given orally, it must pass through membranes in the intestines. It is absorbed and transported to the liver by the hepatic portal vein. From the liver it is then dis- tributed round the body. There can be challenges to oral absorption, e.g. from digestive enzymes, pH of the stomach. Oral medication must be both enzymatic and pH stable.

The design of the medicine has been considered for its route of administration, and therefore should also be administered by the correct route, unless specific guidance has been given to change the route of administration. There have been fatalities when the wrong route of admin- istration has been used.

Different routes for medication administration

Topically (e.g. eyes, ears)

Chloramphenicol eye drops 0.5% or eye ointment 1%

Buccal

Prochlorperazine

Rectal

Diclofenac

Sub-lingual

GTN spray

Intramuscular

Pethidine

Subcutaneous

Fluids – sodium chloride 0.9%

Vaginally

Prostaglandin

Transdermal

Nicotine replacement therapy

Inhalation

Salbutamol

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Activity 15.1

The dose of IV medicines are different from that of oral equivalents.

Can you think of an example of this difference?

Once a medicine has been absorbed, it needs to get around the body to its site of action (to have an effect). This may mean that the medicines will have to pass through membranes and barriers. Distribution can be quite complex and dedicated pharmacology textbooks will discuss this in more detail. Organs and areas of the body which have a rich blood supply (good blood perfusion) will receive medication which is administered quicker than those areas which have a less blood perfusion such as skin, fat, bone tissue.