The raison d'etre of this website is to provide you with hard scientific information which may help you make informed decisions in your quest for health (so far I have blogged concise summaries of over 1,500 scientific studies and have had three books published).

My research is mainly focused on the effects of cholesterol, saturated fat and statin drugs on health. If you know anyone who is worried about their cholesterol levels and heart disease, or has been told to take statin drugs you could send them a link to this website, and to my statin or cholesterol or heart disease books.

David Evans

Independent Health Researcher

Saturday 21 August 2010

Statins associated with decreased libido

This post contains a summary of a study published in the British Journal of Clinical Pharmacology 2004 September; 58(3): 326–328

Study title and authors:
Is decreased libido associated with the use of HMG-CoA-reductase inhibitors?
L de Graaf, A H P M Brouwers,1 and W L Diemont
Statin Drugs Side Effects and the Misguided War on Cholesterol
Books:
Netherlands Pharmacovigilance Centre Lareb, Goudsbloemvallei 7, 5237 MH ‘s-Hertogenbosch, the Netherlands
1General Practice, Pastoor Omenstraat 6, 5121 EN Rijen, the Netherlands
Correspondence L. de Graaf, PharmD, Netherlands Pharmacovigilance Centre Lareb, Goudsbloemvallei 7, 5237 MH ‘s-Hertogenbosch, the Netherlands. Tel: + 31 73 646 9700 Fax: + 31 73 642 6136 E-mail: Email: l.degraaf@lareb.nl

This paper can be accessed at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1884568/?report=abstract
 
The aims of this study were to describe patients with decreased libido during use of statin drugs, and to discuss causality and pharmacological hypotheses for this association. In this Dutch study eight patients were identified as having decreased libido during use of statins.

The study found:
(a) In two of these cases testosterone levels were determined and appeared to be decreased.
(ai) Patient A is a 46-year-old male.
(aii) The patient started treatment with fluvastatin, initially 20 mg daily, increased to 40 mg daily.
(aiii) Shortly after initiation of therapy, the patient noticed a decrease in libido. His testosterone value was measured and determined at 7.2 nmol l−1 (morning value, normal range for adult men 12–35 nmol l−1).
(aiv) Fluvastatin was withdrawn and 5 days later testosterone had increased to 13.2 nmol l−1 (morning value). The patient's libido had also returned to normal.
(b) Patient B, a 54-year-old male, started treatment with pravastatin. 
(bi) Within days after initiation of this therapy, he experienced a decrease in his libido. His testosterone level was determined at 5.8 nmol l−1 (morning value).
(bii) Pravastatin was discontinued seven months later, and after a few days his libido returned to normal.
(biii) Four months later, testosterone level was determined again and had risen to 22.8 nmol l−1 (morning value).
(c) Testosterone levels were not determined in the other six patients (including one woman) although it is known two patients recovered after withdrawal of the statin drugs.
(d) Libido is related to testosterone levels: lower testosterone levels decrease male libido. Testosterone in males is produced mainly from cholesterol in the Leydig cells (found in the testes). Statins may interfere with the synthesis of testosterone in three ways.
(di) By decreasing levels of low density lipoprotein (LDL) cholesterol, statins lower the total amount of cholesterol offered to the Leydig cell.
(dii) Statins are found in the testes and can inhibit the synthesis of cholesterol.
(diii) Statins also interfere with the process that converts two intermediate products, dehydroepiandrosterone (DHEA) and dehydroandrostenedione, into androstenediol and testosterone, respectively. DHEA, dehydroandrostenedione, androstenediol, and testosterone are not just important in men's sexual desire. They are also important in women's sexual desire. This is why some women may also suffer loss of libido when they take statins.

The authors conclude: "Our reports on fluvastatin, pravastatin, simvastatin and atorvastatin and the suggested pharmacological explanation generate the hypothesis that decreased libido may be associated with the use of statins".

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