Doses - PHENOXYBENZAMINE HCL
Note:Because the only dosage form available is a 10 mg capsule, doses should be roundedto the nearest 2.5 mg dose when possible.Dogs:
Treatment of detrusor areflexia:
a) 5 mg - 15 mg PO once daily. (Chew, DiBartola, and Fenner 1986)
b) Initially, 10 mg PO once daily; if no response after 4 days, may increase dose to 10 mg
PO q12h. If after 4 more days there is no response, increase dose to 10 mg PO q8h.(Polzin and Osborne 1985)
c) 2.5 - 30 mg PO tid (Labato 1988)
Treatment of hypertension associated with pheochromocytoma:
a) 0.2 - 1.5 mg/kg PO bid for 10-14 days before surgery; start at low end of dosage rangeand increase until blood pressure reduced to desired range. Propranolol (0.15 - 0.5mg/kg PO tid) may be added to help control arrhythmias and hypertension. Beta-blockers must be used with phenoxybenzamine or severe hypertension may result.(Wheeler 1986)
For adjunctive treatment of endotoxicosis (with appropriate antimicrobial agents, steroids (ifindicated), and other supportive care):
a) 0.25 - 0.5 mg/kg PO q6h. (Coppock and Mostrom 1986)Cats:
Treatment of detrusor areflexia:
a) 0.5 mg/kg PO once daily (Usually 2.5 mg). May increase gradually by 2.5 mg to amaximum of 10 mg. Therapy should be attempted for at least 5 days before evaluationand increase in dose. (Barsanti and Finco 1986)
b) Initially 0.25 mg/kg PO q8h; may gradually increase dose to 0.5 mg/kg PO q8h, ifnecessary. (Polzin and Osborne 1985)Horses:
a) 0.66 mg/kg in 500 ml saline IV (Robinson 1987)
b) 1.2 mg/kg PO, followed in 12 hours by 0.6 mg/kg PO for 2 doses (Schultz 1986)
c) 200 - 600 mg q12h for treatment of profuse, watery diarrhea. (Clark 1988)
Monitoring Parameters - 1) Clinical efficacy (adequate urination, etc.) 2) Blood pressure, ifnecessary/possible
Client Information - Contact veterinarian if animal has continuing problems with weakness, appears dizzy or collapses after standing, or has persistent vomiting. GI upset may be reduced if the drug is given with meals.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times - Veterinary-Approved Products: None
Dogs: 
Treatment of detrusor areflexia: a) 5 mg - 15 mg PO once daily. (Chew, DiBartola, and Fenner 1986)
b) Initially, 10 mg PO once daily; if no response after 4 days, may increase dose to 10 mg
PO q12h. If after 4 more days there is no response, increase dose to 10 mg PO q8h.(Polzin and Osborne 1985)
c) 2.5 - 30 mg PO tid (Labato 1988)
Treatment of hypertension associated with pheochromocytoma:
a) 0.2 - 1.5 mg/kg PO bid for 10-14 days before surgery; start at low end of dosage rangeand increase until blood pressure reduced to desired range. Propranolol (0.15 - 0.5mg/kg PO tid) may be added to help control arrhythmias and hypertension. Beta-blockers must be used with phenoxybenzamine or severe hypertension may result.(Wheeler 1986)
For adjunctive treatment of endotoxicosis (with appropriate antimicrobial agents, steroids (ifindicated), and other supportive care):
a) 0.25 - 0.5 mg/kg PO q6h. (Coppock and Mostrom 1986)
Cats: 
Treatment of detrusor areflexia: a) 0.5 mg/kg PO once daily (Usually 2.5 mg). May increase gradually by 2.5 mg to amaximum of 10 mg. Therapy should be attempted for at least 5 days before evaluationand increase in dose. (Barsanti and Finco 1986)
b) Initially 0.25 mg/kg PO q8h; may gradually increase dose to 0.5 mg/kg PO q8h, ifnecessary. (Polzin and Osborne 1985)
Horses: 
a) 0.66 mg/kg in 500 ml saline IV (Robinson 1987) b) 1.2 mg/kg PO, followed in 12 hours by 0.6 mg/kg PO for 2 doses (Schultz 1986)
c) 200 - 600 mg q12h for treatment of profuse, watery diarrhea. (Clark 1988)
Monitoring Parameters - 1) Clinical efficacy (adequate urination, etc.) 2) Blood pressure, ifnecessary/possible
Client Information - Contact veterinarian if animal has continuing problems with weakness, appears dizzy or collapses after standing, or has persistent vomiting. GI upset may be reduced if the drug is given with meals.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times - Veterinary-Approved Products: None