Preface Prescribing is a core skill for all doctors, and increasingly for non-medical staff. However, they can also cause signifi- cant nephrotoxicity, particularly in renal artery stenosis. Thirdly, what is practicable for the patient? Drug distribution can be affected by the changes in body com- position i. Renal impairment can also occur as a consequence of liver disease, and a reduction in glomerular filtration rate may be important for renally cleared drugs. A loading dose may be needed to achieve the desired effect in a timely manner. Divided into three sections, the first introduces key topics within clinical pharmacology and medicines management including, numeracy, pharmacokinetics, routes of administration, and pharmacodynamics.
If this is the case, it must be made clear in documentation that the process is not com- plete. Written specifically for nurses, it covers the fundamentals of pharmacology as they apply to nursing practice. The main issues are efficacy and safety. In 2006-9, we developed a core list of the 100 most commonly prescribed drugs. Patients may not remember accurate information about the names of medicines or doses.
Some contraindications and interactions are class specific, but bear in mind that some are not. Smaller particle size, higher lipid solubility and weaker ionisation will increase absorption. This can be calculated if conversion from one preparation to another is needed e. Take care not to prescribe a drug to manage an adverse effect from another treatment unless this is unavoidable. It is important to check this before prescribing. Both loading and maintenance doses should be reduced, with a maximum maintenance dose of 125 micrograms suggested half of the normal maximum dose. Hypnotics Benzodiazepines should not be routinely prescribed for insomnia, but often are.
Specific guidance on starting doses and how to titrate a drug may be given along with suggested dose reductions for elderly patients may be supplied for some drug entries. You should think about how to stop the medicine. Timing of dosing is also important. Again this may be straightforward or more complex with instructions to check plasma concentration prior to increasing the dose. Some tablets may be crushed, but not all, so it is important that parents are given appropriate instructions.
It would be wasteful to prescribe these in large quantities. The authors refer to British National Formulary for guidance, and they admit that there isn't one solution and to assist the student they set out their explanations in two parts. From this, a drug that would normally be the first choice for an indication will be selected. With a focus on prescribing, this user-friendly guide helps practitioners to develop crucial knowledge and skills, including establishing accurate drug histories, planning appropriate therapies, writing safe and legal prescriptions, critically appraising the prescribing of others, patient support, accessing reliable information about medicines, and detecting adverse drug reactions. In addition, weight ranges may be used to match rounded doses e. The prescriber should consider the potential risks of overdose, dependence and even selling of treatment. Teens are entirely overlooked and all but one involves non-accidents.
There may be instances where better control of symptoms or conditions can be achieved by varying the time of administration. The infusion will need to go through a syringe pump 50 mL syringes. Are there any other diseases that the patient has which would make the treat- ment unsuitable? Conflicting information may be available, and in many cases drugs are used off-license and therefore no official dose guidance may exist. Permeability of blood-brain barrier Changes in receptor sensitivity Glomerular filtration rate Muscle mass Intrinsic heart rate altered postural response Liver blood flow Enzyme function Total body water Body fat What is different about elderly patients? Review all prescriptions regularly and stop any medi- cines that are not beneficial. Tolerability may also be a consideration. In general, judgements should be made from pub- lished evidence in the form of clinical trials.
For some drugs more detailed information about volumes and timing are given, but this is not universal. Ascites may be worsened by any drug that causes fluid retention e. British National Formulary 66th ed. . Therapeu- tic drug monitoring may be needed to guide dosing.
Open questions — what does the patient think about it? A patient needs an intravenous heparin infusion, to be started at 1200 units per hour. Drugs that are renally cleared may require dose adjustment or avoidance. Many medicines may cause difficulties if stopped abruptly, whether through withdrawal side effects e. Psychiatry at a Glance is the ideal companion for anyone about to start a psychiatric attachment or module and will appeal to medical students, junior doctors and Psychiatry trainees as well as nursing students and other health professionals. Evidence suggests that many risk factors and chronic dis- eases are undertreated. After the introductory chapter the reader is given 50 simulated patient scenarios. Suitability for an individual patient Start with your first-line agent in mind.
Asking about how and when medicines are taken can be useful in identifying misunderstandings or misuse e. It may be to replace a substance that is missing e. For the oral route, bioavailability is variable as some of the drug is lost between the gut and the systemic circulation. Patients scoring in the B or C range of the Child—Pugh classifica- tion moderate or severe disease should be regarded as having hepatic impairment. Body surface area calculations are rarely required in adult medi- cine, except in chemotherapy. Would a change to the standard regimen for the drug help? More recently, it has included guidance from expert bodies. Oral syringes may be helpful for liquid preparations, both in ensuring accurate measuring and also easier administration.
When reviewing medicines, it is worth looking out for these and considering stopping them. Do you ever have diffi- culty with that? You may be able to consult guidelines, whether national or local. In these versions, information about specific drugs in liver disease, renal impairment, pregnancy and breast feeding are in separate appendices at the back. Bear in mind that not all preparations may be stocked locally. Ideal body weight would be 45. It also requires decisions made at this time about stopping or withholding medicines to be noted. Criteria for stopping a drug may be laid down at the outset in some situations.