Pharmacology in clinical practice

• Drug half life
• Therapeutic window
• Clinical duration of action

• Some drugs won't work if given orally or intramuscularly due to its ionisation, molecular weight or lipid solubility
• Some drugs won't distribute into certain body compartments due to their chemical properties (or are selected because they distribute preferentially to target organs)
• Be aware of fetal effects in drugs that cross the transplacental barrier.
• Recommended doses are population averages. Some people become toxic on a low dose, some people require a large dose to get an effect. Be prepared to adjust dose for the individual.
• Before drugs are given orally be aware of a person's gut function and the impact that food may have on absorption
• The onset of administration after oral and intramuscular administration may sometimes be unpredictable
• The dose difference between oral and IV may be considerable due to low oral bioavailability
• Some drugs that are slowly or unevenly distributed may need to be slowly given (or in staggered doses) to prevent toxicity
• The impact of other medications may alter the dose of a prescribed drug (see how drugs interact)
• The presence of liver or kidney disease can affect the dose of a prescribed drug
• Cardiovascular disease (inadequate blood flow) also may affect how quickly a drug takes its effect or indirectly how the liver or kidney handle the drug
• Beware of ceasing a drug quickly (due to down regulation) or long term administration (tolerance and tachyphylaxis)
• Beware of drugs with low TI. You may need to be wary of side effects and monitor drug levels regularly.