Fundamentals of Midwifery: A Textbook for Students (141 page)

Gastrointestinal – diarrhoea vomiting, nausea Hepatotoxicity

Pancreatitis.

Consideration for practice

Allergy status.

The prescribing of antibacterial medicines should follow your Trust antibacterial guidelines/ Health Protection Agency.

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Codeine; Pethidine; Dihydrocodeine

Licensed indication

Usually a prescription only medicine (POM).

Codeine and dihydrocodeine (at low strengths and a maximum pack size) and be brought over the counter, but with a caution for a maximum of 3 days.

Opioids are usually controlled drugs, ranging from Schedule 2, 3 and 5 of the misuse of drug act regulation.

Opioids are used for pain.

Pharmacodynamic

Opioid medication will bind to a variety of opioid receptors within the central nervous system and gastrointestinal system, thus helping with pain (as an agonist action). The extent of respiratory depression and constipation will depend on the individual opioid medication. The pharmacology of opioids can be complex.

Pharmacokinetics

The pharmacokinetics depends on whether the medication is administered orally or intravenously. For example codeine is a pro-drug and is metabolised to morphine and other opioids and then excreted by the kidney.

Contraindications

Opioids should be avoided in patients with acute respiratory depression and increased risk of paralytic ileus.

Caution is needed in hepatic and renal impairment.

Side effects

There are many different side effects depending on which opioid medication. Common side effects include nausea and vomiting, constipation, drowsiness, rash, respiratory depression with larger doses.

Consideration for practice

Access to naloxone (opioid antagonist). Respiratory rate monitoring.

Side effect monitoring.

Paracetamol

Licensed indication

Can be a prescription only medication, a pharmacy (pharmacy) medicine and a general sales list (supermarket) medicine.

Pain and pyrexia.

Pharmacodynamic

The full pharmacodynamics is not known. Paracetamol has analgesic properties and antipyretic effects.

Pharmacokinetics

When given orally it is well-absorbed from the GI tract. It is inactivated by the liver.

Contraindications

Hypersensitivity to the ingredients.

Cautions in alcohol dependence, liver disease and renal disease.

Side effects

Rare.

Consideration for practice

Correct doses must be followed.

Correct weight needed for IV paracetamol.

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Specifically – Diclofenac (PR)

Licensed indication

Prescription only medicine (POM). Licensed for pain and inflammation.

Pharmacodynamic

Anti-inflammatory, nonsteroidal anti-inflammatory drugs (NSAIDs). Inhibits prostaglandin synthesis.

Pharmacokinetics

Absorption is rapid, reaching peak concentration one hour after administration. Is metabolised by the liver and excreted via the kidney.

Contraindications

There are several key contraindications and the British National Formulary or summary of product characteristics should be consulted.

But with respect to midwifery, key contraindications are:

‘During the third trimester of pregnancy, all prostaglandin synthesis inhibitors may expose the fetus to:

cardiopulmonary toxicity (with premature closure of the ductus arteriosus and pulmonary hypertension);

renal dysfunction, which may progress to renal failure with oligo-hydroamniosis. The mother and the neonate, at the end of the pregnancy, to:

possible prolongation of bleeding time, an anti-aggregating effect which may occur even at very low doses;

inhibition of uterine contractions resulting in delayed or prolonged labour.

Consequently, Voltarol is contraindicated during the third trimester of pregnancy’ (eMC 2013).

Side effects

Gastrointestinal, hypersensitivity reactions, headache and dizziness, vertigo, rash.

Consideration for practice

Local practice guidelines should be consulted.

Laxatives

Licensed indication

Most but not all can be brought over the counter. Licensed for the relief of constipation.

Pharmacodynamic

There are several different types of laxatives:

Bulk forming laxatives – (e.g. ispaghula) increasing faecal mass which helps with peristalsis, useful for hard stools.

Stimulant laxatives – (senna) intestinal motility is increased.

Osmotic laxatives – (lactulose, macrogols) increase the amount of water in the bowel.

Pharmacokinetics

See individual drug’s summary of product characteristics.

Contraindications

Bulk forming – difficulty in swallowing, intestinal obstruction, colonic atony and faecal impaction.

Stimulant – acute surgical abdominal conditions, severe dehydration acute inflammatory bowel disease.

Osmotic laxatives – see individual drugs.

Side effects

Bulk forming – flatulence, distension, gastrointestinal obstruction or impaction. Stimulants – nausea and vomiting, cramps.

Osmotic – nausea, vomiting, pain and distension.

Consideration for practice

Involving the patient in the decision-making process with respect to the laxative of choice.

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e.g. Cyclizine, Metoclopramide, Prochlorperazine

Licensed indication

Prescription only medicines (POM). Used for nausea and vomiting.

Pharmacodynamic

Cyclizine – the exact mechanism is not known, it is an H1 receptor antagonist antihistamine. Metoclopramide – affects the parasympathetic nervous system and control in the gastrointestinal system and blocks the Dopamine receptor.

Pharmacokinetics

Cyclizine – well absorbed when given orally, effect within 2 hours and lasts for 4 hours. Metoclopramide – has a half live of 4–5 hours, quick onset of action, excreted in the urine.

Contraindications

Hypersensitivity.

Metoclopramide – gastrointestinal obstruction, phaeochromocytoma, epilepsy.

Side effects

Cyclizine – includes rash, dryness of the mouth, blurred vision.

Metoclopramide – includes extra-pyramidal side effects (EPSE), hyperprolactinaemia, anxiety, restlessness.

Prochlorperazine – includes hyperprolactinaemia, insomnia, dry mouth.

Consideration for practice

Is the patient breastfeeding? (some medication needs to be avoided).

Age of the patient – Metoclopramide may cause EPSE in young people (15–19 years old).

Dalteparin
Licensed indicationPrescription only medicine (POM).Treatment of venous thromboembolism (VTE) presenting clinically as deep vein thrombosis (DVT), pulmonary embolism (PE) or both.PharmacodynamicInhibits Factor Xa and thrombin by antithrombin.PharmacokineticsThe half life following i.v. and s.c. administration is 2 hours and 3.5–4 hours respectively, twice that of unfractionated heparin (eMC 2013).ContraindicationsIncludes ‘history of confirmed or suspected immunologically mediated heparin induced thrombocytopenia (type II); acute gastroduodenal ulcer; cerebral haemorrhage; known haemorrhagic diathesis or other active haemorrhage; serious coagulation disorder; acute or sub- acute septic endocarditis; haemorrhagic pericardial effusion and haemorrhagic pleural effusion; injuries to and operations on the central nervous system, eyes and ears.’ (eMC 2013)Side effectsInclude haemorrhage and pain on injection.Consideration for practiceWhich low molecular weight heparin your organisation uses.337
Medication name/Class: Vitamin K
₁
(phytomenadione)
Vitamin K
₁
Licensed indicationPrescription only medicine (POM). Vitamin K deficiency bleeding.Pharmacodynamic‘Essential for the formation within the body of prothrombin, factor VII, factor IX and factor X, and of the coagulation inhibitors, protein C and protein S.’ (eMC 2013)Pharmacokinetics‘Following oral administration vitamin K
₁
is absorbed from the small intestine. The systemic availability following oral dosing is approximately 50%, with a wide range of interindividual variability. Absorption is limited in the absence of bile.’ (eMC 2013)ContraindicationsHypersensitivity.Side effectsMainly with injections.Consideration for practiceWhat is your local policy?The chief medical officer and chief nursing office have recommended that all newborn babies should receive vitamin K to prevent vitamin K deficiency bleeding.
Numeracy
All nursing and midwifery students need to be numerically competent; this is part of the essen-tial skills clusters for pre registration midwifery education. The standards for pre-registration midwifery education state that students should be able to undertake medicinal product calcula- tions correctly and safely (NMC 2009).There are several books on numeracy for healthcare which are included in the find out more section. However included below are some common areas which students may need to revisit.
Converting fractions into percentages
Percentages are fractions out of 100. Therefore, when converting fractions to percentages you should convert to an equivalent fraction out of 100 and the top number is the percentage.i.e.×25
34 ×2575100 75%
Converting percentages into fractions
As before, percentages are fractions out of 100. So, to convert a percentage to a fraction, make the percentage a fraction out of 100 and then simplify to the simplest fraction.i.e.
40% 40 100
÷10
÷10÷2
4
10 ÷2 2 5338
Converting decimals into percentages
To convert a decimal into a percentage you simply multiply by 100. This means you need to move the decimal place two spaces to the right.i.e.