Navigation Links
ADHD Drug Delays Puberty in Male Monkeys, Study Finds

By Maureen Salamon
HealthDay Reporter

MONDAY, Sept. 19 (HealthDay News) -- The widely used attention-deficit/hyperactivity disorder (ADHD) medication methylphenidate -- best known as Ritalin -- appears to be tied to delayed puberty in male monkeys.

But, researchers cautioned that the finding needs to be replicated before parents should concern themselves about similar effects in boys.

Male primates given methylphenidate over a 40-month span experienced "impaired testicular descent" and smaller-sized testicles, as well as lower testosterone levels, all of which resolved over the course of the study.

"To our knowledge, it's the first observation in primates to suggest an alteration in testicular function," said study author Dr. Donald Mattison, a medical officer at the National Institute of Child Health and Human Development, part of the U.S. National Institutes of Health.

"We believe they're interesting observations, but substantially more work needs to be done . . . to make sure they're repeatable," Mattison said. "It's really too early to say there are clinical implications."

The study is published in this week's online issue of the Proceedings of the National Academy of Sciences.

The most commonly diagnosed behavioral disorder in childhood, ADHD affects between 3 percent and 5 percent of school-age kids, mostly boys. Ritalin and other forms of methylphenidate have long been the most widely used drugs to treat ADHD, which involves issues of inattentiveness, overactivity and impulsivity. Other brand name versions of methylphenidate include Concerta, Metadate and Methylin.

According to Mattison, the young rhesus monkeys in the study were given either a low dose or high dose of methylphenidate, with the low dose designed to match typical blood levels of the drug observed in human ADHD patients. The high dose was intended to produce blood levels five to 10 times higher than used in people, he said.

"Testicular descent," part of the male maturation process, was postponed "significantly" in monkeys given the high (but not lower) dose of methylphenidate, the study found, while lowered testicular volume and blood testosterone levels were noted in monkeys given either the low- or high-dose regimens.

The effects on testicular function were a complete surprise, Mattison noted, since the study was designed to evaluate other types of potential toxicity from methylphenidate, including possible DNA damage.

"I think the results are more to keep in mind, and we haven't made any recommendations for clinical practice," he said. "But we encourage clinicians and scientists to think about puberty as a potential endpoint that might be affected. So we're pretty cautious at this point."

Dr. Spyros Mezitis, an endocrinologist at Lenox Hill Hospital in New York, said hormonal systems are very similar in primates and humans, but he has not observed any testosterone-related symptoms in patients taking methylphenidate.

"This is a standalone study . . . so we need more studies to understand what's happening here," Mezitis said. "In the endocrine community, when it comes to the use of Ritalin, we're not really considering testosterone levels, but maybe we should now."

A spokesperson for Novartis Pharmaceuticals Corp., which manufactures Ritalin, said it was important to note that the study was conducted in monkeys and showed the impact of methylphenidate on puberty was not permanent.

"We have specifically examined our post-marketing data for reports of delayed sexual maturation," spokesman Michael Billings said. "From the data available, no association between the use of our methylphenidate products and delays in sexual maturation has been been established."

More information

There's more on ADHD at the U.S. National Library of Medicine.

SOURCES: Donald Mattison, M.D., medical officer, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Md.; Dr. Spyros Mezitis, endocrinologist, Lenox Hill Hospital, New York City; Michael Billings, spokesperson, Novartis Pharmaceuticals Corp., East Hanover, N.J.; Sept. 19-23, 2011, Proceedings of the National Academy of Sciences

Copyright©2010 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. One-Third of Severe Heart Attack Patients Have Treatment Delays
2. Many Pediatricians Arent Testing Tots for Developmental Delays
3. Hospital Delays Tied to Racial Divide in Heart Attack Care
4. Delays in Hospital Transfers for Heart Attack Patients May Raise Death Risk
5. Language Delays Seen in Kids in Institutions Beyond Age 2
6. Antifungal drug delays need for chemo in advanced prostate cancer
7. FDA Panel Delays Action on Dyes Used in Foods
8. Outcomes improved by longer delays between heart attacks and elective surgeries
9. Blood Pressure Drug Delays Kidney Disease in Diabetics
10. Heart Patients With Depression Often Find ER Delays
11. Delivery Even a Bit Early May Mean Developmental Delays
Post Your Comments:
Related Image:
ADHD Drug Delays Puberty in Male Monkeys, Study Finds
(Date:11/25/2015)... MN (PRWEB) , ... November 25, 2015 , ... ... launched offering factory direct sauna parts and accessories. , Sauna accessories help ... of the bather’s style and personality. From basic styles for the purist looking ...
(Date:11/25/2015)... ... November 25, 2015 , ... According to an ... is being more and more widely heralded as a breakthrough for performing hernia repairs. ... has over traditional laparoscopic surgery is that it can greatly reduce the pain that ...
(Date:11/25/2015)... ... November 25, 2015 , ... The McHenry County law ... successful appellate decision obtained by Attorneys Francisco J. Botto and Alex C. Wimmer. Attorneys ... Workers’ Compensation Comm’n, 2015 IL App (2d) 130884WC. , According to court documents, Adcock ...
(Date:11/25/2015)... ... November 25, 2015 , ... Brillianteen, McGaw YMCA’s student-produced musical ... its 65th Anniversary Brillianteen Revue, scheduled for March 4-6, 2016. Auditions for this ... Brillianteen has been a treasured tradition for numerous families in the Evanston community. ...
(Date:11/25/2015)... Spring, Md (PRWEB) , ... November 25, 2015 ... ... Pulmonary Hypertension Association (PHA) announces the nation’s Periwinkle Pioneers, individuals and groups responsible ... history of this disease. The Periwinkle Pioneers, nominated by the public, will receive ...
Breaking Medicine News(10 mins):
(Date:11/24/2015)...  Array BioPharma Inc. (Nasdaq: ARRY ) ... Ron Squarer , will present at the Piper ... public is welcome to participate in the conference ... Jaffray Annual Healthcare ConferencePresenter:  , Ron Squarer, Chief ... Eastern Time Webcast: , ...
(Date:11/24/2015)... , 24. November 2015 ... Breathing Pacemaker Systems, ist erfreut, die Berufung ... Consultant bekannt geben zu können. ...   --> Foto - ... (Schweden). Von 1984-1986 war er Fellow ...
(Date:11/24/2015)... COMMACK, N.Y. , Nov. 24, 2015 ... Pacemaker System, is pleased to announce the appointment of ... ... and pediatric cardiology at Children,s Hospital, Uppsala University, Uppsala ... . From 1984-1986, he was a fellow at the ...
Breaking Medicine Technology: