How to select pharmacologic treatments to manage recidivism risk in sex offenders
Consider patient factors when choosing off-label hormonal and nonhormonal agents
Cyproterone acetate (CPA), which is available in Canada and Europe, is a synthetic steroid with structure similar to that of progesterone. CPA blocks androgen receptors, which makes it antiandrogenic, progestational, and antigonadotrophic.a
Dosages for paraphilias range from 100 to 500 mg/d orally or 100 to 600 mg intramuscularly every 1 or 2 weeks. b
Once stabilized, some individuals can be maintained on very low doses, such as 12.5 to 50 mg/d. a Lower doses may be appropriate for individuals who are self-motivated for treatment and who reliably report their sexual interests.
CPA reduces testosterone by approximately 50%. Side effects include decreases in:
- erections
- ejaculate volume
- spermatogenesis.
Some patients experience hypersomnia, neurasthenia, weight gain, hot flashes, decreased body and facial hair, and increased scalp hair. About 20% of patients may experience gynecomastia, particularly at higher doses.
Evidence shows CPA reduces sexual arousal, activity, fantasy, and masturbation.a In a systematic review of 7 studies that included 127 patients, the re-offense rate averaged 6%.c This is significantly lower than the expected recidivism of approximately 13.4%.d
References
a. Rösler A, Witztum E. Pharmacotherapy of paraphilias in the next millennium. Behav Sci Law. 2000;18:43-56.
b. Finn DA, Beadles-Bohling AS, Beckley EH, et al. A new look at the 5-alpha-reductase inhibitor finasteride. CNS Drug Rev. 2006;12(1):53-76.
c. Mantzoros CS, Georgiadis EI, Trichopoulos D. Contribution of dihydrotestosterone to male sexual behaviour. BMJ. 1995;310(6990):1289-1291.
d. Hanson R, Bussiere MT. Predicting relapse: A meta-analysis of sexual offender recidivism studies. J Consult Clin Psychology. 1998;66:348-362.
Table 2
Common side effects of antiandrogen therapy
| Depression |
| Erectile dysfunction |
| Fatigue |
| Gynecomastia |
| Hot flashes |
| Hypertension |
| Low libido |
| Myalgia |
| Osteopenia |
| Osteoporosis |
| Sweating |
| Thromboembolism |
| Weight gain |
Monitoring
Laboratory investigations are recommended to monitor for side effects of antiandrogen medications (Table 3).19,27,31 Medical contraindications to rule out before initiating antiandrogen medications include:
- thromboembolic diseases
- liver disease
- bone demineralization disorders
- hypersensitivity to the drug.
Measure prolactin to rule out pituitary adenomas. Monitor serum testosterone because some patients will not experience testosterone suppression from GNRH agonists or other antiandrogens. Noncompliant patients could potentially reverse the effects of MPA and GNRH agonists by taking exogenous testosterone.
Table 3
Monitoring patients receiving antiandrogen medications
| Pre-therapy workup | Periodic monitoring |
|---|---|
| Endocrinology or internist consultation Bone scan Weight Blood pressure Electrocardiogram CBC, renal function, liver function, fasting glucose, and lipids LH, FSH, testosterone, prolactin | Monthly: testosterone for the first 6 months Every 6 months: testosterone, LH, FSH, prolactin, CBC, renal function, liver function, fasting glucose and lipids, weight, blood pressure Yearly: bone scan |
| CBC: complete blood count; FSH: follicle-stimulating hormone; LH: luteinizing hormone | |
| Source: References 19,27,31 | |
Medication selection
The goals of pharmacologic treatment of sex offenders are to:
- reduce sexual offending and victimization
- suppress sexual drive to a controllable level
- possibly preferentially eliminate deviant arousal/thoughts
- allow normal sexual relationships.
Gauging risk. In determining which pharmacologic treatment to offer a patient, first evaluate the individual’s risk for recidivism. Actuarial scales32,33 suggest that recidivism risk can be categorized, based on clinical factors (Table 4).4,25,34
In addition to statistical risk factors, several other factors affect medication selection. Self-referred individuals may be more reliable in taking oral medications than those referred by the courts. A developmentally delayed individual may be a poor candidate for oral medication, unless he resides in a group home setting where compliance can be assured. Efficacy also guides medication choice. Finally, some patients will be legally required to provide proof of compliance, which only IM medications provide.
Treatment. Based on clinical experience and available literature, Bradford5 created an algorithm to help clinicians select appropriate pharmacologic interventions. Although it has not been validated, this algorithm provides a reasonable starting place.
In general, start treatment with an SSRI for low-risk individuals (Table 1).3-5 If this strategy is insufficient, consider augmentation with methylphenidate, naltrexone, or finasteride.
The next step would be to add oral MPA or CPA, 50 mg/d, which would partially inhibit testosterone and may allow some normal sexual functioning.4,23 Higher-dose oral MPA or CPA would be tried next. For higher-risk individuals or treatment failures, IM MPA or CPA would be offered next, followed by a GNRH agonist. For individuals at highest risk for re-offending, combinations of agents may be indicated.
This simple strategy is appealing, but in reality, treatment should be individualized. Choose medications based on the patient’s risk, wishes, and the previously mentioned clinical factors.
Table 4: Will my patient commit another sexual offense? Evaluating risk
Source: References 4,25,34Related resources
- Krueger RB, Kaplan MS. The paraphilic and hypersexual disorders: an overview. J Psychiatr Pract. 2001;7:391-403.
- Krueger RB, Kaplan MS. Behavioral and psychopharmacological treatment of the paraphilic and hypersexual disorders. J Psychiatr Pract. 2002;8:21-32.
- Association for the Treatment of Sexual Abusers. www.atsa.com.
