Advantages and Disadvantages of Different routes of administration

SC Advantage

Absorption is slow but complete. This route is improved by massage or heat. Vasconstrictor may be added to decrease absorption of a anesthetic agent , therefore prolonging its effect at the site of interest

IV ROUTE Disadvantage

Can't reverse a toxic dose, requires specialized personel. May be expensive

Rectal Advantages

By passes liver . It has a reduced first pass effect . This route is useful if patients cant take drugs orally or with young children ( example aspirin, theophylline, chloropromazine and some barbiturates )

Oral Advantages

Convenient ( storage, portability, pre measured dose), economical, non invasive often safer route, requires no special training

Rectal Disadvantages

Erratic absorption-

Buccal / Sublingual Disadvantages

Holding the dose in the mouth is an inconvenience . If any of the drug is swallowed it will then be subject to the fpe

Buccal/ Sublingual Advantages

In this route of administration the liver is bypassed , and bioavailability is higher. This type of administration has rapid absorption

Inhalation

Local effect - bronchodialators Systemic Effect- general anesthesia This type of administration is rapidly absorbed, if it is absorption of gases. solids and gases are excluded if larger than 20 microns and only 10 % of the dose will be absorbed

Topical

Local effects- eyes drops, antiseptic , sunscreen . Used for callous removal

Forms of Pulmonary Delivery

Nebulizer, Dry Powder Inhalers, MDI

Pulmonary Disadvantages

Takes significant degree of coordination. Patients with lung disease may be able to inhale adequately variability in delivery

Factors that influence ocular drug retention

Technique of Application, Drop Size, Formulation (tonicity, viscosity), pH of solution

Parenteral

The routes of administration dont deal with the GI tract. IV, SC, IM

SC Disadvantage

This route may be painful , irritant drugs can cause local tissue damage. Small doses limit use

Intramuscular Disadvantages

Trained personal , the sight of injection will influence the absorption. Absorption is erratic , especially for poorly soluble drugs (diazepam and phenytoin ). The solvent may be absorbed faster than the drug causing precipitation)

IV ROUTE ADVANTAGE

You can deliver drugs in large amounts, you will have 100 percent bioavailability.

Pharmacological agents administered through inhalation for local effects

beclomethasone, terbutaline, cromolyn, metaproterenol, albuterol, pirbuterol

Oral Disadvantages

drug delivery is usually incomplete. Highly dependent on patient compliance .Increased drug- drug, and drug- food interactions . Drugs are exposed to first pass effect

Pulmonary Advantages

easy to titrate dose, rapid onset for local effect, maximize benefit, minimize side effects

Intra arterial

for cancer chemotherapy to maximize drug concentration at the tumor site

Intranasal

has some systemic effects with propanolol

Nasal route

historically used for local effects, their are a growing number of compounds used intranasal that are intended for systemic effects. Used in patients that require drugs to be absorbed but cant use the GI TRACT. (Examples anticonvulsants (midazolam), narcotic antagonists (naloxone), peptides (calcitonin, insulin), and smoking cessation agents (nicotine)

Intramuscular Advantages

larger volume than sc, can be given by IM . A depot or sustained release effect is possible with IM injections ( procaine and penicillin)

Pharmacological agents administered through inhalation for systemic effects

pentamidine, halothane, ergotamine, methoxyflurane, enflurane, isoflurane, nitrous oxide

Enteral

the routes of administration deal with the GI tract. Oral, Rectal , Buccal