1. Enteral Administration
1.1. Oral (PO)
1.1.1. Most common.
1.1.2. Unpredictable absorption.
1.1.3. Poor adherence to schedule dosing.
1.2. Sublingual (SL)
1.2.1. Rapid drug response.
1.2.2. Low doses must be given.
1.3. Rectal (PR)
1.3.1. Patients may be unable to take oral medications.
1.3.2. Variable absorption.
1.4. Buccal
1.4.1. Rapid drug response.
1.4.2. Low doses must be given.
2. Parenteral Administration
2.1. Intravenous (IV)
2.1.1. Injected directly into bloodstream.
2.1.2. 100% absorbed; Rapid onset.
2.1.3. Once injected, drug cannot be retrieved.
2.2. Intramuscular (IM)
2.2.1. Good absorption
2.2.2. Appropriate injection site needed.
2.3. Subcutaneous (SC, SQ)
2.3.1. Good absorption, slower than IM.
2.3.2. Avoids enzymes in the liver.
2.3.3. Doses must be small in volume.
2.4. Intradermal
2.4.1. Patients may be unable to take oral medications.
2.4.2. Avoids enzymes in the liver.
2.4.3. Doses must be small in volume.
2.5. Intrathecal
2.5.1. For local effects within spinal cord.
2.5.2. May have sudden drop in blood pressure.
3. Topical
3.1. Transdermal
3.1.1. Dosing over extended period of time
3.1.2. Cannot give large volume of drug
3.1.3. Not a rapid response
3.2. Subgingival
3.2.1. Local effect to oral mucosa
3.2.2. Only treats localized subgingival areas
3.3. Epicutaneous
3.3.1. Localized effect on the skin
3.3.2. Only treats localized areas
3.4. Inhalation
3.4.1. Rapid drug response
3.4.2. Cannot give large volumes