With the advent of antiparkinsonian therapy, reports of increased libido and sexual performance, hypersexual behavior (with or without concomitant hypomania), and rarely paraphilias have appeared in the literature.11-25 Comparisons cannot be made among studies, as different criteria were used to collect data. Due to the small size of the studies, the incidence of increased sexual drive in patients receiving treatment with antiparkinsonian therapy cannot be determined. The data does not provide a basis for identifying patients who might develop adverse sexual behavior in response to antiparkinsonian medications. Since the initial reports were conducted, medication regimens and dosages have changed. This also affects applicability of reports to current patient care.
Not all early reviews found that levodopa increased sexual behavior.61 A review of 152 patients treated for parkinsonism between 11/1/68 and 7/31//69 did not find significant changes in patients' sexual interests. Increased sexual awareness or activity was reported in 3 to 4 instances. The authors noted that the 5 men in the 40 to 60 year age group, with a relatively mild form of parkinsonism and 1 to 2 year history of impotence, demonstrated improved motor function with therapy but did not report a change in sexual function.
Other reviews described increase in sexual interest and or activity in some patients after L-dopa treatment. Barbeau11 reported an increase in libido in four men after L-dopa therapy. However, erections were not sustained, and men had premature ejaculation. According to Yahr and Duvoisin,12 8% of 283 patients reported improvement in motor function with levodopa and increased sexual activity allowing a return to previous patterns. Hyyppa13 reported that 10 of 41 patients, 7 males and 3 females, treated with 4 to 5 g of L-dopa per day for 2 to 9 months reported increased libido. Three men and two women had markedly increased sexual activity. Two patients reported sexual dreams. One person reported a decrease in libido when L-dopa was decreased from 5 to 3 g.
To assess the effect of L-dopa treatment on sexual behavior in 12 men and 7 women, treated for 3 to 15 months, semistructured interviews were conducted.14 The interviewers assigned numerical values to interview responses. Six men and one woman (37%) reported activation of sexual behavior at some point during the therapy. There were strong negative trends between sexual activity and age of patient (r = -.42) and duration of parkinsonism (r = -.44). Three patterns of change in sexuality were described. In the first pattern, general improvement in overall function was accompanied by mild improvement in sexual function. This result depended on the patient's past sexual habits, age, and availability of a partner. In the second pattern, activation of sexual drive was independent of overall functional improvement. Three (16%) men demonstrated this effect, which was usually mild and did not persist despite continuation of levodopa. The third pattern was loss of sexual inhibition in patients who developed an acute brain syndrome.
Psychiatric interviews, sexual and affective rating scales, hormonal studies, and neurological assessment were used to evaluate L-dopa therapy in 7 men with PD, mean age 62, and mean duration of illness 4 years.15 Four men reported increased sexual interest or activity related to treatment. One man also reported increased interest with placebo.
Levodopa's effect on mood was assessed in 20 patients followed during initiation and maintenance of therapy.16 Six of nine men had spontaneous erections while taking 4 to 6.5 g of levodopa/day. Three of the men had been impotent for up to ten years prior to levodopa therapy and were generally puzzled and embarrassed. The erections were not related to sexual objects and were not accompanied by sexual fantasies. Three of the men reported an increase in libido. One man who had been impotent was able to resume satisfactory sexual intercourse.
Erection has been reported in 5 of 15 men attending a movement disorder neurology clinic as a side effect of treatment with apomorphine injections.17 Erections coincided with apomorphine administration in these patients with motor fluctuations who were offered the apomor-phine to relieve severe symptoms. Four of the men had experienced ED before beginning apomorphine treatment. Two of the men reported improvement in their sexual relationship with their partner as a result of treatment. The one patient that had not experienced ED prior to beginning apomorphine treatment reported undesirable arousal associated with the erections.
Sandyk18 reported on two men with PD and ED, ages 70 and 73, who experienced sexual arousal and nocturnal erections after receiving treatment for PD with transcra-nial administrations of AC-pulsed electromagnetic fields (EMFs) of 7.5 picotesla flux density. The first patient received EMF treatment for two consecutive days. He reported a decrease in parkinsonian symptoms after the first treatment and experienced sexual arousal and awakening during the night with several repetitive spontaneous erections lasting 15 to 20 min. During the second treatment, he experienced sexual arousal. The patient experienced nocturnal erections during the following three nights. The second patient had two successive EMF treatments for four days. This patient reported sexual arousal associated with nocturnal erection.
Hypersexuality is defined as a disturbance of sexuality in which there is a greatly or morbidly increased sexual activity.62 Case reports describe increased masturbation, increased attempts at intercourse with the patients' partner, and initiation of extramarital affairs. Hypersexual behavior is one of the least common adverse psychiatric effects of antiparkinsonian therapy, occurring in less than 1% of patients.25
Hypersexual behavior in adults with PD has been reported as a complication of amantadine, levodopa, sel-egiline, bromocriptine, pergolide, thalamotomy, and high frequency-subthalamic stimulation. Hypersexual responses to therapeutic modalities occurred more often in men and persons with earlier than usual onset of PD. Hypomanic behavior has been associated with hypersex-uality in some but not all patients.11 In some men, excessive libido occurred despite ED. Hypersexual behavior was not always accompanied by improved motor function.
Transient mania with hypersexuality has been reported among 4 of 30 PD patients after high-frequency subthalamic nucleus implant surgery.19 A 57-year-old woman with a history of hypomania during youth developed a marked increase in sexual drive which gradually appeared during the first month, lasted for 18 months, and then gradually resolved. A 54-year-old man with PD for ten years developed increased sexual interest and manic symptoms two months after implant that gradually subsided. Two men with young onset PD developed mania and hypersexuality several days after implant that gradually resolved after several months. When the stimulator was turned off, motor function deteriorated while symptoms of mania persisted. Two cases of transient hypersex-uality following bilateral thalamotomy have been reported. Both patients were sexually overactive prior to thalamotomy.20
Among patients that exhibited hypersexual behavior as a complication of medication therapy, the behavior first appeared after initiation or increase in the dosage of a medication and resolved when the dosage was lowered or the medication was discontinued. Low-dose clozapine has been used to treat dopaminergic-induced psychiatric symptoms, including hypersexuality.63,64 Clozapine improved control of sexual behavior without changing motor scores.63
Was this article helpful?