Alpha Blockers via NG Tube Administration
Doxazosin and terazosin are the preferred alpha blockers for NG tube administration because they are available as immediate-release tablets that can be crushed and dispersed in water without compromising their pharmacokinetic properties. 1, 2
Recommended Alpha Blockers
Doxazosin (First Choice)
- Doxazosin is readily absorbed with high bioavailability that is not influenced by gastric pH or food, making it ideal for NG tube administration 1
- The drug has a relatively long plasma half-life allowing once-daily dosing, which simplifies NG tube medication schedules 1, 2
- Standard dosing: Start at 1 mg once daily, titrate at 2-week intervals up to 2-8 mg daily as needed 2
- Maximum hypotensive effects occur 4-8 hours after administration 2
Prazosin (Alternative Option)
- Prazosin can be administered via NG tube as it is available in immediate-release capsules that can be opened 3
- Requires twice-daily dosing for 24-hour blood pressure control, which is less convenient than doxazosin 3
- Causes dose-related decreases in blood pressure with selective alpha-1 receptor antagonism 3
Critical Administration Technique
Tube Preparation and Flushing
- Flush the NG tube with at least 30 mL of water before, between, and after each medication to prevent tube occlusion 4, 5
- Use appropriate ENFit-standard syringes and connectors to avoid misconnection errors 4, 5
- Administer medications individually through the tube—never mix multiple drugs together 4, 5
Medication Preparation
- Crush tablets thoroughly and disperse in water immediately before administration 6, 7
- Consult with a pharmacist before crushing any medication to confirm appropriateness 5
- Consider the site of drug delivery, as absorption occurs primarily in the stomach and proximal small bowel 4
Important Safety Considerations
First-Dose Hypotension
- Initiate doxazosin at 1 mg daily to minimize orthostatic hypotension after the first dose, which occurs infrequently but requires monitoring 2
- Monitor blood pressure closely, particularly standing blood pressure 2-4 hours post-administration 1
Tube Placement Verification
- Confirm the NG tube tip location is in the stomach using pH testing prior to every use 8
- Administration distal to the stomach (e.g., directly into duodenum) may result in reduced drug availability 4
- Fine bore (5-8 French gauge) NG tubes should be used unless high viscosity medications require larger tubes 8
Common Pitfalls to Avoid
- Do not administer extended-release or modified-release formulations of alpha blockers via NG tube, as crushing destroys the controlled-release mechanism 6, 7
- Avoid mixing crushed alpha blockers with enteral nutrition formulas, as this may cause drug-formula interactions 5, 7
- Do not shake low-dose ENFit syringes to remove drug residue, as this affects the dose delivered 5
- Never assume bioequivalence between oral and nasogastric administration without confirming absorption characteristics 7