What antihypertensive (antihtn) medications can be administered via a Gastrostomy Tube (GTube)?

Antihypertensive Medications for G-Tube Administration

Most oral antihypertensive medications can be crushed and administered via G-tube, with ACE inhibitors, ARBs, thiazide diuretics, and long-acting calcium channel blockers being preferred first-line agents, but extended-release and enteric-coated formulations must be avoided. 1

First-Line Agents Suitable for G-Tube Administration

The following drug classes are recommended as first-line antihypertensives and have formulations or extemporaneous preparations suitable for G-tube administration:

ACE Inhibitors

• Lisinopril is ideal for G-tube administration as it does not require biotransformation for activity and can be crushed or prepared as an extemporaneous liquid (1 mg/mL) 1, 2
• Enalapril can be prepared as extemporaneous liquid (1 mg/mL) and administered once or twice daily 1
• Both agents provide 24-hour blood pressure control with once-daily dosing, simplifying administration through feeding tubes 2

Angiotensin Receptor Blockers (ARBs)

• Valsartan is available as extemporaneous liquid (4 mg/mL) for once-daily administration 1
• Irbesartan can be prepared as extemporaneous liquid (2 mg/mL) for once-daily dosing 1
• ARBs are equally effective as ACE inhibitors and may be preferred if cough develops 1

Thiazide and Thiazide-Like Diuretics

• Hydrochlorothiazide tablets can be crushed for G-tube administration 1
• Chlorthalidone is preferred over hydrochlorothiazide due to longer duration of action and superior cardiovascular outcomes 1
• Thiazide-like agents are recommended over traditional thiazides when available 1

Calcium Channel Blockers

• Amlodipine tablets (immediate-release) can be crushed and administered via G-tube 1
• Nifedipine immediate-release can be used, but extended-release formulations must NOT be crushed 1
• Long-acting dihydropyridine CCBs are preferred for renal protection and once-daily dosing 1

Formulations to AVOID via G-Tube

Extended-Release Preparations

• Do NOT crush: Metoprolol succinate (extended-release), propranolol LA, carvedilol phosphate, or any SR/ER/LA formulation 1
• Extended-release mechanisms are destroyed by crushing, leading to dangerous immediate drug release and loss of 24-hour coverage 1

Enteric-Coated Tablets

• Crushing destroys protective coating and may cause drug degradation in gastric acid 1

Beta-Blockers for G-Tube Use

While not first-line for uncomplicated hypertension, beta-blockers may be necessary for specific indications:

• Metoprolol tartrate (immediate-release) can be crushed for twice-daily administration 1
• Carvedilol (immediate-release) can be crushed for twice-daily dosing in heart failure patients 1
• Atenolol tablets can be crushed for once-daily administration 1
• Avoid abrupt cessation of all beta-blockers to prevent rebound hypertension 1

Additional Agents for Resistant Hypertension

Mineralocorticoid Receptor Antagonists

• Spironolactone is recommended as 4th-line agent for resistant hypertension and can be prepared as extemporaneous suspension 1
• Use only if serum potassium <4.5 mmol/L and eGFR >45 mL/min/1.73m² 1

Alpha-Blockers

• Doxazosin tablets can be crushed but are associated with orthostatic hypotension, especially in elderly patients 1
• Consider as second-line in patients with benign prostatic hyperplasia 1

Critical Administration Considerations

Tube Flushing Protocol

• Flush G-tube with 30 mL water before and after each medication 1
• Administer each medication separately to prevent drug interactions and tube clogging 1
• Never mix multiple crushed medications together 1

Monitoring Requirements

• Monitor blood pressure monthly after initiation or dose changes until target achieved 1
• Follow up every 3-5 months once blood pressure controlled 1
• Check serum potassium and renal function when using ACE inhibitors, ARBs, or spironolactone 1

Common Pitfalls to Avoid

• Never use clonidine patch as substitute without tapering oral clonidine first, as abrupt discontinuation causes hypertensive crisis 1
• Avoid hydralazine and minoxidil as first-line agents; they cause reflex tachycardia and sodium retention requiring additional medications 1
• Do not use immediate-release nifedipine for chronic hypertension due to lack of renoprotection and blood pressure variability 3
• Verify tablet can be crushed before administration; when uncertain, contact pharmacy for extemporaneous liquid preparation 1

Target Blood Pressure Goals

• Target <130/80 mm Hg for patients with known cardiovascular disease or 10-year ASCVD risk ≥10% 1
• Target <140/90 mm Hg for patients without additional cardiovascular risk markers 1
• More intensive targets (<130 mm Hg systolic) recommended for high-risk patients with diabetes or chronic kidney disease 1