Have to add, that in whole, effect of above mentioned medications in treatment of premature ejaculation are not enough and this effect has not been statistically counted. In last couple years there have showed up studies regarding efficiency of intracavernous injections of vasoactive preparations for correction of premature ejaculation. Perhaps one of the mechanisms of extension of friction stage with intracavernous therapy is decrease of sensitivity of nervous structures of the penis because of them being squeezed by cavernous bodies gaining their adequate rigidity.
Possibly, role also plays self-assurance of the man who believes that he will successfully finish the coitus after receiving his intracavernous injection. Though, key is the fact, that with pharmacological erection, it is still holding on after ejaculation which allows patient to proceed with intercourse. With newest experimental and clinic researches there has been demonstrated ability of different pharmacological preparations to affect selectively different mechanisms of ejaculation regulation.
Modern level of pharmacology development allows putting into practice therapy of premature ejaculation much more effectively.
Ejaculation is inhibited by neuroleptics due to blockage of dopamine receptors at a central level. This group of medicines is also known as antipsychotic preparations. Premature ejaculation is prevented by centrally working blockaders of dopamine receptors. Neuroleptics have not been widely used in treatment of premature ejaculation.
Ejaculation is minimally inhibited by tranquillizers – derivatives of benzodiazepine, preparations which increase concentration of Gamma-amino-butyric acid (GABA) and activating its work in brain. Their affect on ejaculation is most likely dose-dependant. They include such medications as diazepam (seduxen), lorazepam and alprazolam. Their effect on ejaculation though is not as expressed and controlled studies showed that slower ejaculation occurs only for less than 10% of men using these medications, besides effect is dose-dependant. Low efficiency and expressed soporific effect limits the use of mentioned preparations in therapy of ejaculation dysfunctions.
In some level, ejaculation is delayed by alpha-adrenergic blockaders (for example, phenoxybenzene) due to them slowing down sympathetic link of ejaculatory reflex. Perhaps this mechanism is conditioned by blockage of alpha-1 adrenoreceptors. Phenoxybenzamine slows down the reception of sperm into back part of urethra and delays ejaculation, although orgasm usually is present. This preparation haven’t been widely used in clinical practice of premature ejaculation treatment because of its frequent side-effect – retrograde ejaculation. Different studies has shown ability of phenoxybenzamine slow down ejaculation up until its loss in 4,5-100% of cases, if taking 5-70 mg big dose of phenoxybenzamine a day.
Ejaculation I also inhibited by tricyclic energizers (antidepressants), which have anticholinergic and alpha-adrenergic qualities and increase the level of monoamines, including serotonin, due to blockage of their recapture. This effect is dose-dependant. In this group of preparations are included clomipramin (anafranil) and amitriptyline. They have quickly expressed and dose-dependant effect and pretty often, especially clomipramin, are used in therapy of premature ejaculation. Though, tricyclic agents are less “clear”, less selective in their effect on certain serotonergic synapses. They also have more side-effects. Antidepressant inhibitors of monoamine oxidase (MAO), for example, phenelzine cause delay of ejaculation for 10-50% of patients. Considering low efficiency and plenty of side-effects, they are practically not used in treatment of premature ejaculation.
Many antidepressants increase the level of serotonin due to selective blockade of its recapture. The newest preparations of this group are paroxetine, fluoxetine (prozac), sertraline (zoloft). It’s been determined that they all are effective, have dose-dependant effect and small amount of side-effects. Preparations of this group are considered to be more perspective for treatment of premature ejaculation. At the current moment it’s been worked on comprehensive assessment of these preparations in therapy of sexual dysfunctions. Modern medical tactics of treatment in cases of inflammatory lesions of accessory genital glands, prostatic part of urethra or seminal knob are described in details in many publications.