prescribing

• Prescribing


  To advise and authorize the use of a medicine or treatment for a patient by a health practitioner in writing
• Health institutions often have individualized prescription forms for purposes of prescribing
• A prescription can be written on paper as long as all necessary legal elements are present
• As a Medical practitioner you are equipped with knowledge to prescribe and use drugs in a rational way
• Prescription


  • Legible and signed clearly for optimal communication between the prescriber and other members of the health care team
  • Contains sufficient information to permit a pharmacist or nurse to dispenser or administer the drug correctly
• Elements of a valid prescription


  • Date
  • Patient's name
  • Patients address (DDA)
  • Age
  • Sex
  • Weight (infants)
  • Name of the drug
  • Dose of the drug
  • Route of administration
  • Frequency of taking the drug
  • Duration of treatment
  • Name, number and signature of the prescriber
• Prescription should have generic drug names only and avoid non-official abbreviations
• Rational drug use


  Patients receive medications appropriate to their clinical needs, in doses that meet their own individual requirement, for an adequate period of time and at the lowest cost to them and their community
• Rational drug use helps to


  • Optimize patient outcomes
  • Enhance compliance to medicines
  • Ensure that all access to drugs is accompanied by adequate information
  • Eradicate unnecessary and inappropriate drug use at all levels in the society
  • Save resources
• Cost-effectiveness


  Applies to cost-benefit, cost-minimization, and cost-utility analyses to compare the economics of different pharmaceutical products or to compare drug therapy to other treatments
• Placebo


  • A substance containing no medication and prescribed or given to reinforce a patient's expectation to get well
  • An inactive substance or preparation used as a control in an experiment or test to determine the effectiveness of a medicinal drug
  • Intended to deceive the recipient
• Patients given a placebo treatment will sometimes have a perceived or actual improvement in a medical condition, a phenomenon commonly called the placebo effect
• Placebos are widely used in medical research and are given as control treatments and depend on the use of measured deception
• Drug dosage calculations


  Necessary when patients are prescribed doses of a drug which are not precisely equivalent to standard presentation, to calculate the quantity of drug preparation which will contain the prescribed dose
• Drug dosage calculations are a common source of error in drug administration
• Standard measurements used in drug preparations


  • Weights: 1000 nanograms (ng) = 1 microgram (mcg), 1,000 micrograms (mcg) = 1 milligrams (mg), 1000 milligrams (mg) = 1 gram (g), 1000 grams (g) = 1 kilogram (kg)
  • Volumes: 1 millilitre (mL) = 1 cubic centimetre (cc), 1000 millilitres (ml) = 1 litre (L), 100 millilitres (ml) = 1 decilitre (dL), 1 Litre of water at 4℃ weighs 1 kilogram
  • Domestic Measures: 1 teaspoonful = 5ml, 1 dessertspoonful = 10ml, 1 tablespoonful = 15ml, 1 tumblerful = 250mls
• Calculating volume to be administered


  Divide the amount required by amount available and multiply by volume in stock
• Calculating number of tablets/capsules to be administered

  Required Amount / Available Amount
• Clark's Rule


  Child's dose = Weight of child x Adult dose/ Weight of Adult
• Infusion sets


  Macro drop factor - 20 drops deliver 1ml, Micro drop factor - 60 drops deliver 1ml
• Calculating drops per minute for IV infusion


  Drops per minute = Volume to be given X Drop factor / Time factor
• Drug interactions


  The pharmacologic activity of a drug is altered by the concomitant use of another drug or by the presence of some other substance
• Types of drug interactions


  • Addition or Summation
  • Synergism or Potentiation
  • Antagonist
  • Liver enzyme Inducers/Inhibitors
• Drug interactions are mostly undesirable but rarely desirable