Understanding the physiology of ejaculation is important in
implementing a proper treatment strategy for ejaculatory disorders. However, the
neurophysiology and dynamics of emission and ejaculation have only been partly elucidated
and much research still needs to be done.
The existence of multiple neurotransmitters and receptors has long
been recog- nized, and the recent discovery of new neuroactive substances in nerve
terminals has opened new horizons in understanding the neurophysiology of ejaculation.
Ejaculatory disorders can be grouped into two major groups: emission
disorders and ejaculation disorders. Many conditions, drugs and environmental factors may
affect seminal emission. Organic causes of seminal emission disorders include various
surgical procedures; for example, anemission may be a consequence of bilateral
retroperitoneal lymph node dissection.
The most common ejaculation disorders are premature ejaculation,
retrograde ejaculation, retarded ejaculation and anejaculation. Others include ejaculation
during defecation and painful ejaculation.
Retrograde ejaculation, where the ejaculate is directed backwards
into the bladder, may be caused by true or functional sympathectomy, bladder neck
incompetence due to organ disruption, diseases such as hyperprolactinemia, and certain
drugs (e.g. methyldopa, phenoxybenzamine, prazosin, clozapine and thioridazine).
Retarded ejaculation may have an organic cause (e.g. certain
diseases, surgical interventions, neurological and endocrinological factors, and drugs
such as dopamine antagonists, antidepressants and anxiolytics), but is often related to
psychological factors, in particular anger or resentment towards women.
Anejaculation is classified as primary, when ejaculation has never
been experienced, or secondary, when normal ejaculation has preceded its onset. Causes
include psychological factors (e.g. a sexually repressive upbringing, gender confusion,
anxiety, marital problems, fear of causing pregnancy) and organic causes such as prostatic
and bladder neck surgery, diabetes mellitus, spinal cord injury and posterior urethral
stricture.
Premature ejaculation is the most common male sexual disorder, and
affects more than 30% of men. Criteria for defining premature ejaculation include failure
to achieve orgasm by the partner, duration of intercourse until ejaculation, number of
intravaginal thrusts until ejaculation, and the criteria specified in the Diagnostic and
Statistical Manual (DSM-IV) of the American Psychiatric Association.
Premature ejaculation is further classified as being primary (from
the first sexual experience) or secondary (when normal sexual functioning precedes onset);
persistent or recurrent; and organic or psychogenic in origin. Organic causes include
trauma to the sympathetic nervous system, pelvic fractures, prostatic hypertrophy,
prostatitis, diabetes, arteriosclerosis, cardiovascular disease, local genitourinary
disease, generalized neurological disease, and localized sensory impairment.
Treatment of premature ejaculation includes pharmacological therapy,
surgical procedures (which should be limited to patients with severe penile
hypersensitivity), and behavioral therapies (which are beneficial to only a minority of
patients in the long term).
Pharmacological agents that have provided some benefit in premature
ejaculation include dopamine antagonists (e.g. antipsychotics such as pimozide, sulpiride,
haloperidol, chlorpromazine and thioridazine), selective serotonin reuptake inhibitor
antidepressants (e.g. fluoxetine, sertraline and paroxetine) and some tricyclic anti-
depressants (e.g. clomipramine), anxiolytics (e.g. chlordiazepoxide, lorazepam and
alprazolam), phenoxybenzamine, topical anesthetics, and various other preparations such as
the herbal formulation `SS-cream'.
In treating ejaculatory disorders, clinicians need to understand the
cultural back- ground of the patient in order to gain a comprehensive view of the problem.
Full discussion of the history with spouses should be undertaken to arrive at a correct
diagnosis and to evaluate the efficacy of treatment.
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