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Fundamentals of Pharmacology for Paramedics


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number of authors have suggested standard methodologies to ensure that the correct approach to medicines use is followed every time, especially under high‐stress conditions. The following mnemonic for the assessment of patients was developed by ISMP Canada:

      SAMPLE

       Signs

       Allergies

       Medication

       Past pertinent history

       Last oral intake

       Events leading to injury

      Students of paramedicine are usually familiar with the golden rules of safe administration of medicines, published as 10 golden rules (McGovern, 1992) but also appearing in shortened forms. These rules stipulate that when giving any medication:

      1 Give the right drug

      2 To the right patient

      3 In the right dose

      4 Via the right route

      5 At the right time

      6 Explain about the medication to your patient

      7 Take a complete medication history

      8 Find out about any allergies

      9 Know about potential drug interactions

      10 Document each medication administration.

      These rules serve as a guide for safe administration of medicines in the field, but they can also be a useful guide to learning pharmacology. Learning what drugs do and how they do it; who they can be given to and when caution should be exercised; what dose ranges they should be used in; by what routes they can be administered and the correct timing of their administration via these routes; what drugs they cannot be combined with and why, are all part of the pharmacology every student of paramedicine must learn and continue to add to as they gain professional experience and as new medicines become available. The need to be a lifelong learner is never more pressing than in the field of clinical pharmacology.

      Companies selling medicines are required by law to provide basic information about the medicine for patients before it is made available to them. In the UK, this information is known as the Patient Information Leaflet (PIL), and in Australia it is the Consumer Medicines Information (CMI). The aim of this information is to educate patients about their medicines so that they can ensure they are taking them safely and effectively.

      This information includes:

       What the medicine is used to treat (the indications of the medicine)

       Warnings about when the medicine should not be taken (the contraindications of the medicine)

       Warnings about when the medicine should be taken with caution

       Other medicines that should not be combined with the medicine (known as interactions)

       Possible side‐effects (known as adverse effects)

       The dose to take and any special instructions regarding how to take the medicine

       What to do in the case of an overdose of the medicine

       How to store the medicine.

      The language used in these documents has been chosen to make the information accessible to any patient, hence the avoidance of too much technical language, but it is nonetheless the same information that health professionals need in order to ensure the safe and effective administration of medicines to their patients.

      Skills in practice

      The decision about whether to administer or withhold a medication requires a process of clinical reasoning, based on your assessment of the patient, their medical and medication history and the indications and contraindications of the medication.

       An unconscious child who is hypoglycaemic is indicated for glucose 10% administration. The signs used here as indications for the medication are both the finding of hypoglycaemia and the child’s level of consciousness.

       A 50‐year‐old male patient who is experiencing crushing left‐sided chest pain has an indication for aspirin administration, provided you have established that he has no abnormal bleeding tendencies.

      Sometimes, despite there being an indication for a medication, you will not be able to administer it because of a contraindication. A contraindication is a reason to withhold medication because it might cause harm to the patient, as in the following examples:

       Aspirin is contraindicated for analgesia and fever in paediatric patients who are under 16 years of age because of the risk of Reye’s syndrome. The syndrome is quite rare and only occurs in children, but is very serious.

       Ipratropium, a bronchodilator commonly used with salbutamol for the treatment of bronchospasm, is usually contraindicated in patients who have glaucoma, as a known side‐effect is an increase in intraocular pressure.

       Amiodarone is an antiarrhythmic indicated for tachyarrhythmias (cardiac arrhythmias which involve an increased heart rate), but contraindicated in torsades de pointes, a potentially fatal tachyarrhythmia which can result from long QT syndrome, because amiodarone will result in further protraction of the QT interval.

      As data about medications are gathered, indications and contraindications may change, so it is important to remain abreast of these changes in your practice as a paramedic.

      Episode of care

      You attend a 49‐year‐old male patient complaining of left‐sided central chest pain. He is diaphoretic, pale and short of breath.

      You ask him about his medical history. He reports he has a ‘high blood pressure problem’. You glance at his medication list and do not recognise any common antihypertensive medications.

      Your check his observations and gain a detailed history, while preparing him for a 12‐lead ECG. The ECG suggests a lateral myocardial infarct. Your provisional diagnosis is acute coronary syndrome and you proceed with administering aspirin and a vasodilator.

      En route he rapidly becomes hypotensive with a decreased level of consciousness. At hospital, you discover he has recently commenced on a vasodilator for aggressive management of his pulmonary hypertension. This medication was not on his medication list.

      You may see medications that patients are taking for indications other than the listed indications. Vasodilators such as sildenafil (Viagra®) and vardenafil (Levitra®) are often prescribed to males for erectile dysfunction, but can also be used to treat pulmonary hypertension.

      Patients may be unsure what they are taking medications for and it is imperative to gain a detailed history prior to administration of any medication to ensure contraindications are not encountered. Medications can be used for purposes other than their primary indication.

      Every drug will have a number of names. Knowing the correct name of a drug is vital in the prevention of medication errors, and becomes even more important when drugs can be identified by several different names. All drugs will have an individual chemical name which conveys very accurately (at least to a chemist!)