Pharmacology: Calculations (Terms)

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is administered 30 minutes before the meal (breakfast) and becomes effective in 1 to 2 hours. Its duration of action in the body is 12 to 18 hours. This type of insulin contains protamine, which prolongs the action in the body. It is cloudy because of the protamine added to the regular insulin. It can only be given subcutaneously.
Lantus and Levemircannot be mixed with other insulins or given intravenously.DOSAGE CALCULATIONSare the basic everyday type of calculations you will be doing on the ward. They include calculating number of tablets or capsules required, divided doses, simple drug dosages, and dosages based on patient parameters, e.g. weight and body surface area.Percentagecan be defined as the amount of ingredient of drugs in 100 parts of the productsBody surface area (BSA)estimates is more accurate than using body weight.njection's displacement valuethe final volume of the injection will be greater than the volume of liquid that was added to the powder.Displacementthe dry powder injections need to be reconstituted with a diluent before they are used.Displacement valueswill depend on the medicine, the manufacturer and its strength. Information on a medicine's displacement value is usually stated in the relevant drug information sheets, in pediatric dosage books or can be obtained from your pharmacy department.Drops/minmainly encountered when infusions are given under gravity as with fluid replacement.mL/hris encountered when infusions must be given accurately or in small volumes using infusion or syringe pumps.IV infusionsare a common sight on hospital wards, and the majority of patients will have IV infusions as a part of their treatment.IV fluidsshould not be considered simply as a means of administering drugs or as plasma expanders. Inappropriate use can lead to imbalances in electrolytes, acid-base disturbances and fluid imbalances.Waterhas an important role in the normal function of the body. Its major function is as a transport system for nutrients and waste products. Also, the kidneys require a minimum of 500 to 700 mL to maintain normal renal function, and the lung surface must be 'wet' to allow gaseous exchange.Wateris also important in the maintenance of blood volume. Therefore, it is important to maintain an adequate fluid balance.correct balance of electrolytes(such as sodium, potassium, magnesium and calcium) is important in electric conduction and muscle contraction.Intakeis from the normal diet (food and drink), and loss is mainly due to excretion as urine and feces.Lossis also from sweat (skin) and water vapour from the lungs. The last two are difficult to measure and so are termed insensible losses and are based on approximations.Crystalloidsare clear fluids made up of water and electrolytesIsotonicwhich have the same osmolarity as plasma, e.g. sodium chloride 0.9%, sodium chloride 0.18%/glucose 4%, glucose 5%, Hartmann'sHypotonicwhich have a lower osmolarity compared to plasma, e.g. sodium chloride 0.45%Hypertonicwhich have a higher osmolarity compared to plasma, e.g. sodium chloride 3%, glucose 10%, sodium chloride 0.45%/glucose 5%Colloidsdo not contain any electrolytes but are solutions that contain large molecules that do not readily leave the intravascular space. This makes them hypertonic and they exert an 'osmotic pull' on the fluid in the interstitial and extracellular spaces. Examples include gelatins.fluid balance chartmonitors a patient's fluid status by recording fluid intake and output, usually over a 24-hour period.Fluid intakeis usually by oral liquid, food, enteral and infusion fluids; output is usually by urine, vomiting, diarrhea, sweat or via drains.Gravity devicesuse standard solution sets and flow is measured by counting the drops.Drip rate controllerslook like a pump but have no pumping mechanism.Pumped systemsVolumetric or syringe pumps are the most common.Volumetric pumpshese pumps are the preferred choice for medium and large volume intravenous or enteral infusions, although some are designed specifically to operate at low flow rates for neonatal use. The rate is given in millilitres per hour (typical range 1-999 mL/hour).Syringe pumpsThese are used to administer drugs or infusions in small or medium volumes, and are calibrated for delivery in millilitres per hour, typically 0.1 to 99 mL/hour.Patient-controlled analgesia (PCA) pumpsare typically syringe pumps, as the total volume of drug infused can usually be contained in a single-use syringe.Anaesthesia pumpsThese are syringe pumps designed for use in anaesthesia or sedation and must be used only for this purpose; they are unsuitable for any other use. They should be restricted to operating and high dependency areas.Pumps for ambulatory useAmbulatory pumps have been designed to allow patients to continue receiving treatment or therapy away from a hospital, thereby leading a normal life during treatment.Syringe driversThese pumps are designed to deliver drugs accurately over a certain period of time (usually 24 hours).