phenoxybenzamine hydrochloride: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
phenoxybenzamine hydrochloride: clinical details
Prescribing considerations
- Reserve for specialist management of phaeochromocytoma-associated hypertensive episodes.
- Assess benefit and risk where alternatives are suitable because preclinical carcinogenicity and mutagenicity findings are described.
- Establish alpha blockade before introducing a beta blocker for catecholamine-related tachycardia.
- Anticipate postural hypotension, reflex tachycardia and prolonged pharmacological effects.
Contraindications and cautions
- Hypersensitivity to phenoxybenzamine or an excipient.
- Previous cerebrovascular accident.
- The recovery period following acute myocardial infarction.
- The capsule should not be used in people with galactose intolerance, total lactase deficiency or glucose-galactose malabsorption.
Monitoring
- Seated and standing blood pressure and heart rate.
- Symptoms of hypotension, tachycardia, nasal congestion and gastrointestinal intolerance.
- Cardiovascular and renal tolerance, particularly in older people and those with severe heart, cerebrovascular or renal disease.
- Perioperative haemodynamics and volume status when used for surgical preparation.
Clinical pharmacology
A non-competitive, long-acting alpha-adrenoceptor antagonist. Gastrointestinal absorption is incomplete; it is metabolised in the liver and eliminated in urine and bile. Stable covalent receptor binding produces prolonged effects.
Formulation and product differences
- The selected evidence covers an oral hard gelatin capsule containing lactose, talc and colourants.
- No alternative formulation is represented by the selected product information.
phenoxybenzamine hydrochloride preparations and strengths
Capsule
Route: Oral
Strengths: 10 mg
phenoxybenzamine hydrochloride interactions
The full medicine list should be reviewed because cardiovascular effects may be altered or intensified.
Beta blockers
For phaeochromocytoma, beta blockade must not precede adequate alpha blockade because this can trigger a dangerous hypertensive crisis.
Other blood-pressure-lowering medicines, including ACE inhibitors and calcium-channel blockers
Combined treatment may increase low blood pressure and postural dizziness, requiring clinical monitoring.
Alpha-sympathomimetics
Alpha-receptor blockade may alter their cardiovascular response, so concurrent use requires specialist consideration.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.