testosterone undecanoate

Action and Spectrum

Actions and spectrum: 

The compound’s active ingredient, testosterone, is released into the bloodstream when endogenous non-specific esterases cleave testosterone undecanoate. Pharmacologically, the undecanoate side chain is inert. 5α reductase can further convert testosterone to dihydrotestosterone (DHT), which is more physiologically active.

The androgen receptor, which is widely expressed in many tissues, including the bone, muscle, prostate, and adipose tissue, mediates the actions of testosterone and DHT. With a strong affinity for androgen receptors, testosterone controls the transcription of target genes essential for the healthy growth and development of male sex organs as well as the preservation of secondary sex traits. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Erectile dysfunction 

Hot flashes 

Enlarged prostate 

Pain at the site of injection 

Acne 

Weight gain 

Anxiety 

Baldness in male 

Increased or decreased sexual interest 

Headache  

Hair loss 

Trouble sleeping 

Black Box Warning

Black Box Warning  

No special warnings for this drug are available 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

Liver failure 

Cardiac disease 

Renal failure 

Polycythemia Vera 

Prostate cancer 

Hyperlipoproteinemia Type III 

Breast cancer 

Hypertension 

Pregnancy / Lactation

Pregnancy consideration:  

USFDA pregnancy category: X 

Lactation:  

The use of this drug is contraindicated in lactating mothers as it is known to be excreted in breast milk. 

Pregnancy category:  

Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester. 

Category B: There was a lack of studies on pregnant women and no evidence of risk to the fetus in animal experiments.   

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.   

Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacology: 

The ester prodrug of testosterone is testosterone undecanoate, which has a mid-chain fatty acid at carbon 17β. It was created by esterifying testosterone with fatty acids to produce testosterone that could be taken orally. 

Pharmacodynamics: 

Once in the bloodstream, testosterone undecanoate is broken down to produce testosterone, which functions as a biological mediator for several different processes. As an endogenous male hormone, testosterone regulates hematopoiesis, body composition, and bone metabolism, all of which are essential aspects of male sexual differentiation.

For males with hypogonadism, testosterone undecanoate is an exogenous source of testosterone used in hormone replacement therapy. The main aim of testosterone therapy is to enhance the signs and symptoms of low levels of testosterone, such as diminished libido, erectile dysfunction, and loss of bone and muscle mass. 

Pharmacokinetics:  

Absorption 

After 750 mg of testosterone undecanoate was injected intramuscularly, serum testosterone concentrations peaked after a median of seven days (with a range of four to 42 days), after which they gradually decreased. After injecting testosterone undecanoate, on the fourth day, the mean (SD) Cmax was approximately 90.9 (68.8) ng/dL.

By the time the third injection was administered at 14 weeks, the serum testosterone concentration had stabilized. Forty-two days after the injection, there was hardly any testosterone undecanoate present. 

Distribution 

40% of testosterone is bound to SHBG (sex hormone-binding globulin), and 2% is unbound 

Metabolism 

5α-reductase can convert testosterone undecanoate to dihydrotestosterone undecanoate. Endogenous non-specific esterases in the bloodstream cleave the ester bond that connects testosterone to undecanoic acid. The undecanoic side chain, like all fatty acids, is converted to acetyl CoA and then propionyl CoA by β-oxidation.  

Dihydrotestosterone (DHT) and estradiol are the two primary active metabolites of testosterone, which are produced by two distinct pathways that convert testosterone to various 17-keto steroids. 

Elimination and excretion 

Approximately 90% of intramuscularly administered testosterone is excreted through urine as conjugates of sulfuric acid and glucuronide. About 6% of the unconjugated form is excreted through feces.  

Half-life: 

2 hours 

Adminstartion

Administration: 

Take testosterone undecanoate with or without meals 

Patient Information Leaflet

Patient information leaflet 

Generic Name: testosterone undecanoate  

Why do we use testosterone undecanoate? 

In adult males with conditions linked to a lack of endogenous testosterone, testosterone undecanoate is recommended as a testosterone replacement therapy. It is indicated for treatment in adult males with primary hypogonadism and hypogonadotropic hypogonadism.