APO Prazo contains prazosin hydrochloride, a prescription medication belonging to the alpha 1 adrenergic receptor blocker class. APO Prazo 1mg is manufactured by Apotex and is currently listed by Health Canada as a marketed prescription medication in Canada.
Prazosin works by selectively blocking postsynaptic alpha 1 adrenergic receptors. These receptors normally respond to norepinephrine and contribute to contraction of vascular smooth muscle. Blocking alpha 1 signaling causes blood vessels to relax and widen, reducing peripheral vascular resistance and helping lower blood pressure.
This mechanism makes prazosin an established antihypertensive medication. Unlike some blood pressure medications, its primary effect is produced through peripheral alpha 1 blockade rather than direct beta receptor inhibition or suppression of the renin angiotensin system.
Alpha 1 receptors are also present in smooth muscle throughout other areas of the body, including the bladder neck and prostate. Relaxation of smooth muscle is therefore an important part of prazosin’s overall pharmacological profile, although APO Prazo’s established Canadian therapeutic classification is as an antihypertensive medication.
Prazosin has additionally developed an important off label role in the management of trauma related nightmares, particularly nightmares associated with post traumatic stress disorder (PTSD). The 2023 VA/DoD clinical practice guideline suggests prazosin specifically for PTSD associated nightmares, while recommending against its use as a treatment for overall PTSD symptoms. Evidence is considered limited and treatment should therefore be individualized.
This product provides:
- Active Ingredient: Prazosin
- Form: Prazosin Hydrochloride
- Strength: 1mg per tablet
- Quantity: 100 Tablets
- Brand: APO-Prazo
- Manufacturer: Apotex
- Drug Class: Alpha-1 Adrenergic Receptor Blocker
- Dosage Form: Oral Tablet
- Primary Use: Management of High Blood Pressure
Health Canada currently lists APO Prazo 1mg tablets as marketed prescription medication, alongside 2mg and 5mg APO Prazo strengths.
An important characteristic of prazosin therapy is the potential for a pronounced first dose blood pressure effect. Alpha blockers can cause postural or orthostatic hypotension, resulting in dizziness, light headedness or, less commonly, fainting when standing. Prescribing information notes that syncopal episodes have occurred most often shortly after the initial dose or following rapid increases in treatment.
The 1mg strength is commonly used when initiating prazosin therapy because lower initial exposure helps reduce the risk of excessive blood pressure reduction. Current prescribing information specifically notes that treatment initiation with 1mg can reduce the frequency of first dose syncope compared with higher starting doses.
Other potential adverse effects can include dizziness, headache, weakness, fatigue, palpitations, nausea and drowsiness. These effects may be more noticeable when treatment is first started or when the dose is adjusted.
Additional caution is required when prazosin is combined with other medications that lower blood pressure. Significant hypotension can occur when it is combined with certain antihypertensive agents, and blood pressure lowering effects may also be increased by medications used for erectile dysfunction or other drugs that cause vasodilation.
APO Prazo is a prescription medication and should be used according to the directions and monitoring recommendations of a qualified healthcare professional.
