Metabolism and elimination are both reduced in the baby.
Equally, the fetus eliminates the medicines taken by the mother into the amniotic luid, which is then ingested again. Consequently some medicines such as magnesium sulphate may still have an effect on the neonate for around 48 hours after delivery.
Summary
•
Pharmacokinetics is the absorption, distribution, metabolism and excretion of drugs.•
Pregnancy affects pharmacokinetics and optimal plasma concentrations may take longer to attain.|
18| Chapter
Principles of drug administration: legal aspects, pharmacokinetics and anaphylaxis
•
As a second line of treatment, an antihistamine (chlorphenamine) 10 mg can be administered intramuscularly or by slow intravenous injection (neonatal dose 250 microgram/kg).•
Following initial resuscitation, hydrocortisone 200 mg may be administered intramuscularly or by slow intravenous injection (neonatal dose 25 mg initially).•
If bronchospasm persists, administration of a bronchodilator may be required, e.g. nebulized/intravenous salbutamol, inhaled ipratropium, intravenous aminophylline or magnesium (the latter may cause further lushes and hypotension).
•
Blood should be taken to measure mast cell tryptase.This aids the diagnosis of anaphylaxis. The irst specimen should be taken as soon after the reaction as is convenient, the second is taken 1–2 hours post the event and the third is taken after 24 hours.
•
Document the cause and management clearly, informing the woman of this (to avoid recurrence).•
Closely observe the woman or baby’s condition over the next 6 hours in a clinical area able to monitor and treat life-threatening conditions, a secondary reaction may occur. Observation is required for at least 24 hours, following a serious anaphylactic reaction.•
Following an anaphylactic reaction, referral to an allergy clinic should be made for follow-up consultation and management (NICE 2011). It may be necessary for the client to carry adrenaline for potential self-administration in the future.Where an actual or suspected adverse drug reaction has occurred, the midwife should report this in the UK to the Medicines and Healthcare Products Regulatory Agency (MHRA) using the yellow card scheme. This can be under-taken online: www.yellowcard.mhra.gov.uk or by complet-ing the yellow card at the back of the British National Formulary (BNF). Such monitoring exists in most countries.
resulting in confusion and cyanosis (late sign), fatigue, respiratory arrest.
•
Circulation – shock, tachycardia, hypotension, dizziness, collapse, loss of consciousness, myocardial ischaemia and electrocardiograph (ECG) changes, cardiac arrest.•
Disability problems – the problems encountered with airway, breathing and circulation changes decrease brain perfusion and can alter the woman’sneurological status causing agitation, confusion and loss of consciousness. There may also be
accompanying GI symptoms of abdominal pain, vomiting, incontinence, diarrhoea.
•
Mucosal and/or skin changes – erythema, urticaria, angioedema.Management of severe anaphylaxis (Resuscitation Council 2008)
•
Call for medical assistance urgently; do not leave the woman.•
If anaphylaxis is the result of a substance being administered, stop administration immediately.•
Position the woman in the left lateral position.When this is not possible and the woman is on her back, place a wedge under her right side to prevent aortocaval occlusion (if pregnant) and raise her legs.
•
Follow the principles of resuscitation (Chapter 55) using ABCDE, establish an airway and resuscitate as needed while treating the anaphylaxis.•
Administer 100% oxygen therapy using a high-low mask (>10 L/min) with an oxygen reservoir to prevent collapse of the reservoir during inspiration.•
Administer intramuscular adrenaline (epinephrine) 1 : 1000 solution (1 mg/mL); repeated at 5-minute intervals if needed (adult dose 500 micrograms, 0.5 mL; under 6 yrs 150 micrograms, 0.15 mL). If repeated doses are required, intravenous adrenaline may be administered only by a doctor who uses this in their everyday practice, e.g. anaesthetist.Continuous ECG and pulse oximetry will be required with frequent monitoring of blood pressure.
•
To correct hypotension, shock, and vasodilation, administer 500–1000 mL intravenous crystalloid solution (e.g. 0.9% sodium chloride) rapidly. If hypotension persists, administer further doses.•
Anticipate the need for a chest X-ray, blood samples for urea and electrolytes, blood gases, etc., as for any emergency. If pregnant, rapid caesarean section may be required, depending upon the mother’s response to resuscitation. At some point fetal monitoring should be attempted.ROLE AND RESPONSIBILITIES OF THE MIDWIFE These can be summarized as:
• being familiar with pharmacokinetics and the implications for drug administration
• understanding how pregnancy affects pharmacokinetics
• understanding why pharmacokinetics is different for the baby
• asking about known allergies at the booking interview and on each admission to hospital where medication may be required
• recognizing and managing anaphylaxis correctly
• correct documentation
• informing the MHRA of a suspected or actual adverse drug reaction.
skin changes, with respiratory or cardiovascular collapse. The immediate management includes the giving of I.M. adrenaline and action as for cardiopulmonary resuscitation.
•
Where an actual or suspected drug reaction has occurred, the midwife should notify the MHRA who are responsible for monitoring such events.Summary
•
Anaphylaxis is a rare but potentially fatal reaction that can result from (amongst other things) drug administration. It is recognized by a sudden and worsening response following administration of the trigger. The woman may experience mucosal and/orSELF-ASSESSMENT EXERCISES
The answers to the following questions may be found in the text:
1. From where can ‘P’ classiied medicines be obtained?
2. What does a midwife need to know about a medicine before they can administer it?
3. Which medicines can a midwife administer autonomously under Midwives Exemptions?
4. List the nine ‘rights’ of medicine administration.
5. What information is needed on a correctly completed prescription?
6. List the steps taken to ensure that (a) a non-controlled drug and (b) a controlled drug are correctly
administered.
7. Describe the ways in which a midwife could access pethidine for a woman labouring at home.
8. Describe how a woman can be assessed for suitability for self-medicating.
9. What are the four aspects of pharmacokinetics?
10. How does pregnancy affect pharmacokinetics?
11. How would the midwife recognize and manage anaphylaxis?
12. What is the name of the agency that monitors adverse drug reactions?
REFERENCES
Alexis, O., Caldwell, J., 2013.
Administration of medicines- the nurse role in ensuring patient safety. Br. J. Nurs. 22 (1), 32–35.
Anon (Anonymous), 2010. Changes to midwives exemptions. Pract. Midwife 13 (7), 8.
Bussey, A., 2011. What is a Patient Group Direction (PGD)? Available online:
<http://www.medicinesresources .nhs.uk/en/Communities/NHS/
PGDs/FAQs/What-is-a-Patient-Group -Direction-PGD/> (accessed 5 March 2015).
Elliott, M., Liu, Y., 2010. The nine rights of medication administration: an overview. Br. J. Nurs. 19 (5), 300–305.
GMC (General Medical Council), 2013.
Good practice in prescribing and
managing medicines and devices.
GMC, London. Available online:
<www.gmc-uk.org/guidance>
(accessed 15 December 2015).
Grifith, R., 2010. Law, medicines and the midwife. In: Jordan, S. (Ed.), Pharmacology for Midwives, second ed. Palgrave Macmillan, Basingstoke, pp. 62–74. (Chapter 3).
Human Medicines Regulations, 2012.
Available online: <http://www .legislation.gov.uk/uksi/2012/1916/
made> (accessed 26 February 2015).
Jackson, M.P., 1999. Impact of age, pregnancy, disease and food on drug action. In: Luker, K., Wolfson, D.
(Eds.), Medicines Management for Clinical Nurses. Blackwell Science, Oxford. (Chapter 4).
Jordan, S., 2010. Principles of Pharmacology. In: Jordan, S. (Ed.),
Pharmacology for Midwives, second ed. Palgrave Macmillan, Basingstoke.
(Chapter 1).
Matthew, L., 2007. Injectable medication therapy: a patient safety challenge.
Nurs. Stand. 21 (31), 45–48.
NICE (National Institute for Health and Clinical Excellence), 2011.
Anaphylaxis: assessment to conirm an anaphylactic episode and the decision to refer after emergency treatment for a suspected anaphylactic episode. NICE Guideline 134.
Available online: <www.nice.org.uk/>
(accessed 5 March 2014).
NMC (Nursing and Midwifery Council), 2007. Standards for medicine management. NMC, London.
Available online: <http://www.nmc-uk .org/Publications/Standards/>
(accessed 5 March 2015).
|
18| Chapter
Principles of drug administration: legal aspects, pharmacokinetics and anaphylaxis
NMC (Nursing and Midwifery Council), 2011. Changes to Midwives
Exemptions. NMC Circular 07/2011.
NMC, London. Available online:
<www.nmc-uk.org> (accessed 5 March 2014).
NMC (Nursing and Midwifery Council), 2012. Midwives Rules and Standards.
NMC, London.
Resuscitation Council UK, 2008.
Emergency treatment of anaphylactic reactions. Guidelines for healthcare
providers. Available online:
<www.resus.org.uk> (accessed 5 March 2015).
Principles of drug administration:
oral administration
Chapter
The majority of medication taken via the mouth (orally) is absorbed by the gastrointestinal tract, often in the stomach. However, the distinction is made between medi-cation that is swallowed and that which is held in the mouth.
•
Medication to be given orally is swallowed, ‘p.o.’ is the agreed abbreviation.•
Buccal refers to medication that is absorbed through the vessels in the mouth; in this case the medication is lodged in the cheek. On a medicine administration record (see Chapter 18) ‘buccal’ is often written in full and not abbreviated.•
Sublingual preparations sit under the tongue. They are often abbreviated as ‘s.l.’. Both these and buccal preparations avoid the gastrointestinal tract, enter the circulation directly via the superior vena cava, and therefore have a rapid response. Jordan (2010) suggests that if there has not been a response within 5 minutes of receiving the medication, then there is not likely to be one.•
Lozenges are often sucked (systemic effect) or used for local effect, e.g. anaesthetic relief of sore throats, antifungal coating of the tongue. Some medications are chewed, this should be clear in the prescription.Oral medication
Ansell & Dougherty (2011) suggest there are distinct advan-tages in using the oral route for medication. It is often an easy and convenient route without too much disruption or embarrassment, and often the medications are the least expensive. However, for some situations alternative routes or preparations may be needed:
•
Compliance: is the woman/baby awake, suficiently alert, understanding, and physically able to swallow?19
CHAPTER CONTENTS
Learning outcomes 154
Oral medication 154
Equipment 155
Education 155
PROCEDURE: oral administration to
a woman 155
Precautions 156
Oral administration to a baby 156 PROCEDURE: oral administration to
a baby 156
Role and responsibilities of the midwife 156
Summary 157
Self-assessment exercises 157
References 157
LEARNING OUTCOMES
Having read this chapter, the reader should be able to:
•
discuss the advantages and disadvantages of the oral route, identifying what should be included in a risk assessment•
describe the different preparations available for oral use, giving an example of each•
describe the procedure for administering a drug orally to a woman and a baby•
summarize the role and responsibilities of the midwife.This chapter considers the safe management of medication for the oral route, the preparations available and the role and responsibilities of the midwife. The procedures are described for adult and neonatal administration. It should be read in conjunction with Chapter 18.