ADMINISTRATION ROUTES:
PO, NG
ALTERNATIVE NAMES:
Dosan, Apo-Doxazosin
ICU INDICATIONS:
- Hypertension refractory to other oral agents
- Patients may also be taking this medication at the time of ICU admission for benign prostatic hypertrophy (it is usually appropriate to withhold doxazosin given for this indication)
PRESENTATION AND ADMINISTRATION:
PO:
Apo-Doxazosin 2mg (white), Apo-Doxazosin 4mg (white), Dosan 4mg (white)
DOSAGE:
PO / NG:
Begin at 1 mg OD
Increase as required to max 16 mg daily
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Dose as in normal renal function
DOSAGE IN PAEDIATRICS:
PO:
0.02 - 0.1 mg/kg daily
CLINICAL PHARMACOLOGY:
Doxazosin mesylate is a selective inhibitor of the alpha1-subtype of alpha adrenergic receptors
CONTRAINDICATIONS:
- Known hypersensitivity to doxazosin
WARNINGS:
First-Dose Effect:
Doxazosin, like other alpha-adrenergic blocking agents, can cause marked hypotension, particularly with the first dose
Priapism:
Doxazosin may cause priapism; if this occurs, urgent urological advice is required
PRECAUTIONS:
General:
Doxazosin should be administered with caution to patients with evidence of impaired hepatic function
Laboratory Tests:
No tests additional to routine ICU tests are required
Drug/Laboratory Test Interactions:
None known
IMPORTANT DRUG INTERACTIONS IN ICU:
Hypotension is more likely to occur when doxazosin is combined with other antihypertensives
ADVERSE REACTIONS:
Body as a Whole:
Malaise
Cardiovascular System:
Dizziness, hypotension
Skin & Appendages:
Rash
Central & Peripheral Nervous System:
Headache, paraesthesia, muscle cramps, somnolence
Gastrointestinal System:
Nausea, diarrhoea, constipation
Respiratory System:
Rhinitis