Prescribing by different routes Flashcards
When deciding how to administer a drug, what factors should you consider?
Bioavailability, desired peak-trough levels, release time, availability/tolerability of route, contraindications and risks.
When would you consider using IV administration of a drug?
100% bioavailability; better to be given in circumstances where regular, smaller doses can be administered, such as in a hospital setting
How much liquid can you give via subcutaneous injection per day?
48ml/24hr
Which mode of administration is contraindicated in haemophilia?
Intramuscular injection
When might you consider administering a drug via an intramuscular route?
entry of small volume with fast entry into the systemic circulation
Why may hyaluronidase be used alongside an intramuscular injection?
Allows breakdown of the ECM to increase the rate of diffusion (uptake)
What is meant by ‘intrathecal’ adminstration?
Injection into the dura mater around the spinal cord
When may you administer a drug intrathecally?
Injection into the dura mater around the spinal cord may be used for single-dose analgesia e.g. Baclofen for spasiticity
What complication may occur with intrathecal drug administration?
Respiratory depression
What is meant by an ‘epidural’?
Where an injection of a drug is given just above the dura mater of the spinal cord
Why may you choose to administer a drug epidurals rather than intrathecally?
Epidural - a large volume can be administered by this method by comparison, and there is the potential to insert an in-dwelling catheter to allow for drug top-up
Describe the intranasal route of drug adminstration
Nasal mucosa is highly vascularised; so decongestants can be used in this way, but also systemic drugs e.g. desmopressin etc.
When might you consider giving a medication per rectally?
Vomiting/nausea/NBM or IV access is difficult to obtain (e.g. status epilepticus)
When may you consider giving a drug buccally or sublingually?
If a drug is unstable at gastric pH or are rapidly metabolised by the liver; oral mucosa facilitates very quick absorption
When might you use intraosseous drug administration?
Cardiopulmonary arrest or paediatric resuscitation –> drugs administered into the medullary cavity of the long bones (usually tibia or fibula)
