Nonparenteral administration refers to the delivery of medications through routes that do not involve injections. Instead, drugs are administered via the digestive tract, mucous membranes, skin, or inhalation, making it less invasive and often more comfortable for patients compared to parenteral (injection-based) routes.
This method is widely used in hospitals, clinics, and home care settings. Understanding the different routes, techniques, and contraindications is essential for safe and effective drug delivery.
1. Oral or Enteral Administration
Definition: Medications are given by mouth and absorbed through the digestive tract.
Key Guidelines:
- Contraindications: Avoid oral administration in patients with vomiting, aspiration risk, absence of gag reflex, decreased level of consciousness, or difficulty swallowing.
- Have the patient sit upright at a 90° angle to prevent aspiration.
- Do not crush enteric-coated or time-release medications.
- Only cut or break scored tablets.
Advantages:
- Easy, convenient, and non-invasive.
- Wide variety of drug forms (tablets, capsules, syrups).
Limitations:
- Slower onset compared to injections.
- Affected by GI conditions, food, and drug interactions.
2. Transdermal Administration
Definition: Medication delivered through a patch applied to the skin, absorbed into the bloodstream over time.
Key Guidelines:
- Apply to dry, clean, hair-free skin.
- Rotate application sites to prevent skin irritation.
- Always remove old patches before applying a new one.
Examples:
- Nicotine patches (smoking cessation)
- Fentanyl patches (pain management)
- Hormone replacement therapy
Advantages: Provides continuous drug release over hours or days.
3. Inhalation Administration
Definition: Medication delivered directly into the respiratory tract via inhalers or nebulizers.
Key Guidelines:
- Rinse the mouth after using steroid inhalers to prevent oral thrush.
- Wait 20–30 seconds between puffs of the same medication.
- Wait 2–5 minutes between different inhaled medications.
- Use a spacer device to improve drug delivery.
Examples:
- Asthma inhalers (salbutamol, corticosteroids)
- Nebulized bronchodilators
- Oxygen therapy
Advantages: Rapid onset due to direct absorption in the lungs.
4. Sublingual and Buccal Administration
Definition: Medication placed under the tongue (sublingual) or between the cheek and gum (buccal) for absorption through oral mucosa.
Guidelines:
- Sublingual: Place the tablet under the tongue until fully dissolved.
- Buccal: Place between the cheek and gum until absorbed.
- Do not chew, eat, or drink until absorption is complete.
Examples:
- Sublingual nitroglycerin (angina relief)
- Buccal fentanyl tablets (pain control)
Advantages:
- Rapid absorption directly into circulation, bypassing the liver (avoids first-pass effect).
5. Suppositories
A. Rectal Administration
- Position patient in lateral or Sims’ position.
- Use lubrication before insertion.
- Insert beyond the internal sphincter.
- Leave in place for at least 5 minutes.
Examples: Antiemetics, laxatives, analgesics.
B. Vaginal Administration
- Patient lies supine with knees bent.
- Insert suppository 3–4 inches along the posterior vaginal wall.
- Stay supine for at least 5 minutes to allow absorption.
Examples: Antifungals, hormonal medications.
Advantages: Useful when oral route is not possible (vomiting, unconsciousness).
6. Installation (Drops, Ointments, Sprays)
A. Eye (Ophthalmic)
- Tilt head back slightly.
- Pull down lower eyelid to expose conjunctival sac.
- Hold dropper 1–2 cm above the sac.
- Apply gentle pressure on the nasolacrimal duct for 30–60 seconds to reduce systemic absorption.
B. Ear (Otic)
- Tilt head to the side.
- Warm solution before use to prevent dizziness.
- Adults: Pull ear up and outward.
- Children (<3 years): Pull ear down and back.
C. Nose (Nasal)
- Have patient lie supine.
- Avoid blowing the nose for 5 minutes after instillation.
Examples: Antibiotic eye drops, ear infection drops, nasal decongestants.
Comparison of Nonparenteral Routes
| Route | Key Features | Common Uses | Advantages | Limitations |
|---|---|---|---|---|
| Oral | Swallowed, GI absorption | Antibiotics, analgesics | Convenient, safe | Slow onset, GI issues |
| Transdermal | Patch on skin | Hormones, pain, nicotine | Continuous release | Skin irritation |
| Inhalation | Through lungs | Asthma, COPD | Rapid action | Technique-dependent |
| Sublingual/Buccal | Under tongue or cheek | Angina, pain | Avoids first-pass metabolism | Limited drug types |
| Suppositories | Rectal/vaginal | Laxatives, antifungals | Useful when oral not possible | Uncomfortable |
| Installation | Drops/ointments | Eye, ear, nose | Local action | Requires precision |
Safety Considerations
- Aseptic technique: Always use clean hands or gloves.
- Patient positioning: Correct posture enhances absorption and prevents aspiration.
- Timing: Follow dosing schedules strictly.
- Education: Teach patients how to self-administer inhalers, patches, or drops correctly.
- Monitoring: Watch for side effects, allergies, or lack of therapeutic response.
Frequently Asked Questions (FAQs)
Q1. Why should enteric-coated tablets not be crushed?
Because they are designed to dissolve in the intestines, crushing them destroys protection and can cause stomach irritation or alter absorption.
Q2. What’s the difference between sublingual and buccal administration?
Sublingual is under the tongue, while buccal is between the cheek and gum. Both provide rapid absorption and bypass the liver.
Q3. Why rotate transdermal patch sites?
To prevent skin irritation and ensure consistent absorption.
Q4. How long should patients remain supine after a vaginal suppository?
At least 5 minutes to allow for absorption and prevent expulsion.
Q5. Why is nasolacrimal pressure important after eye drop administration?
It prevents systemic absorption of the drug, reducing side effects.
