| What is parenteral route of administration? | IV, IM and SC.
Introduced directly into systemic circulation or tissues.
100% Bioavailability, used for hardly absorbed drugs (like insulin and heparin), unconscious pts, and in case we need to yield rapid onset of drugs.
Not subject to first pass
they are irreversible, cause damage fear infection... |
| How is the IV route of entry? | In aqueous solution form, since complete and rapid bioavailability.
Could be given as a bolus (all in one go, but should take some time in order to dilution in blood to occur and not be toxic) or as continuous infusions
Can cause infections |
| How is the IM route of entry? | Could be aqueous solution or depot preparation (oily/ supension which can be absorbed slowly, such as polyethylene glycol)
Used for sustained release drugs (for longer time usage) like haloperidol and medroxyprogesterone
Can be modulated by heating, massage or exercise which increases blood flow.
Drugs that are too irritating to SC are given IM. |
| How is the SC route of entry? | Used for not too irritating drugs (that may cause necrosis or damage)
Constant and slow to provide sustained effect.
Administring vasoconstrictors may be used to delay the absorption and increase the sustained effect (like lidocaine local anesthetics incorporate epinephrine in its dosage)
Some drugs may be as devices implanted under the skin after an incision.
Heparin and Insulin are introduced SC |
| What are the advantages of PRL administration? | Delivery in active form (like infliximab or remicade Ab)
Rapid, predictable delivery
Accurate
Used for unconscious pt who cant swallow |
| What are the disadvantages of PRL administration? | Asepsis, pain and difficulty self medication |
| What is the intrathecal route of administration? | Injection into the spinal canal and further into subarachnod space and CSF, useful in spinal anesthesia, chemo and radiotherapy |
| What is the pulmonary route of absorption? | Gases and volatile drugs are given for systemic effect and are easily absorbed
Some drugs are as particles aerosols local effect and maybe systemic (like Salbutamol for bronchial asthma)
No first pass
Important for drugs of abuse and toxins (nicotine, opium) |
| What is the topical route of administration? | Either through mucus membrane or through the skin
Through mucus membrane, used for local effects, drugs enter circulation rapidly, may be systemic effect (ADH nasal), or local anesthetics (xylocaine gel)
Through the skin, should penetrate through the epidermis primarily (either through the appandanges or through it itself) |
| What types of particles enter through topical? | very small and polar molecules.
passive diffusion (anelgesics like NSAIDs and Ibuprofen)
Facilitated diffusion (fentanyl opoid anelgesic for pain management)
Inflammation can increase absorption by increasing the blood flow to the dermis
Hydrated skin is more permeable. |
| Give examples of topical patches. | nicotine for tobacco-smoking withdrawal,
scopolamine for motion sickness,
nitroglycerin for angina pectoris,
testosterone and estrogen for replacement therapy. |
