Centrally acting antihypertensive drugs & Adrenergic Neuron Blockers
- Adrenergic neurone blocking action by preventing the granular uptake of catecholamines where it stays outside the granules (in the cytoplasm) to be inactivated by MAO enzyme.
- Parasympathomimetic action.
The hypotension effect is due to:
- Adrenergic neurone blocking action.
- Central action (inhibition of VMC and tranquilization)
- Depletion of suprarenal medulla.
Adverse Effects:
- Bradycardia, flushing and nasal stuffiness. (parasympathetic actions due lost sympathetic)
- Hyperacidity, peptic ulceration, salivation and diarrhea.
- Loss of libido and impotence in males.
- Salt and water retention.
- Psychic depression (Due to deficient norepinephrine) , suicidal attempts, parkinsonian-like rigidity and nightmares, cancer breast.
Uses :
- Less common nowadays due its side effects.
- Not alone but as part of combination therapy for treatment of hypertension.