Current Cardiovascular Drugs, 1995, 2nd Edition, William H Frishman.
Phentolamine. Regitine Ciba-Geigy
Caveat!!!! Parenthesis comments are from cacaito.
Contraindications: Myocardial infarct, Angina, Coronary Insuficiency,
other coronary artery disease,peptic ulcer, gatritis, or history of.. (well most probably almost any of the other drugs will also be contraindicated in these conditions).
Interactions: epinephrine, norepinephrine, arginine, propranolol, ephedrine(use for nasal stuffiness)diazoxide,guanadrel, guanethidine,
alcohol. (only alcohol, propranolosl and ephedrine are of common use).
Adverse effects: tachycardia, fainting, gastric disturbances, weakness,orthostatic hypotension, acute hypotensive episodes, stuffy nose, flushing, arrhytmias, constipation, retrograde ejaculation.
(of course the most serious side effects are much less frequent).
Pharmacokinetics for the intravenous use:
Duration of action: brief 5 to 10 minutes
Plasma half life: 19 minutes
Onset of action: for IV is immediate
Bioavailability: less than 20% of the drug is absorbed from the gatrointestinal tract. (One of Zonagen claims is that they indeed improved this to the point of good absorption with their "new patentable formulation").
Prolonged Use: Associated with loss of antihypertensive efficacy and marked tachycardia. (this is good for Vasomax in terms of less hypotension, but it could be a problem if this lack of efficacy is found on the pro-erection effects).
In Healthy individuals phentolamine has little effects on blood pressure (good for Vasogen).
In patients with systemic hypertension phentolamine has little effects on blood pressure ( could this mean that in patients with arterial
damage as the basis for their ED, it will has little effects?). |
