Multisystem evaluations of the long-term effects of tibolone on postmenopausal monkeys.

Abstract

This long-term study (2 years) was designed to compare the effects of tibolone (LoTib at 0.05 mg/kg and HiTib at 0.2 mg/kg) with those of conjugated equine oestrogens (CEE) alone (0.042 mg/kg) and CEE continuously combined with medroxyprogesterone acetate (MPA) (0.167 mg/kg) on coronary artery atherosclerosis, bone, mammary gland and uterus in ovariectomised cynomolgus monkeys fed a moderately atherogenic diet. Despite reductions in plasma concentrations of high density lipoprotein cholesterol in tibolone-treated monkeys, there was no exacerbation of coronary artery atherosclerosis. Tibolone was equivalent to, or slightly better than, CEE and CEE + MPA in protecting against postmenopausal bone loss and loss of bone strength. Tibolone also resulted in less stimulation of breast and endometrial tissue compared with CEE and CEE + MPA. In conclusion, the results suggest that tibolone is a cardiovascular-safe treatment that is effective for the prevention of osteoporosis and that may have advantages over CEE or CEE + MPA with regard to endometrial and breast safety.

• Authors: T B Clarkson, M S Anthony, J M Cline, C J Lees, A G H Ederveen
• Journal: Maturitas (Maturitas) Vol. 48 Suppl 1 Pg. S24-9 (Aug 30 2004) ISSN: 0378-5122 [Print] Ireland
• PMID: 15337245 (Publication Type: Journal Article)

Chemical References

• Estrogens, Conjugated (USP)
• Norpregnenes
• Selective Estrogen Receptor Modulators
• tibolone

Topics

• Animals
• Coronary Vessels (drug effects)
• Dose-Response Relationship, Drug
• Estrogens, Conjugated (USP) (administration & dosage, pharmacology)
• Female
• Longitudinal Studies
• Lumbar Vertebrae (drug effects)
• Macaca fascicularis
• Mammary Glands, Animal (drug effects)
• Menopause
• Models, Animal
• Norpregnenes (administration & dosage, pharmacology)
• Ovariectomy
• Random Allocation
• Selective Estrogen Receptor Modulators (administration & dosage, pharmacology)
• Uterus (drug effects)