First ever Testosterone Nasal Gel… Natesto.


Generic: Testosterone. 

Brand: Natesto.

Manufacturers: Trimel Pharmaceuticals.

Approval status: approved in May 2014.

Indication: for deficiency or absence of endogenous testosterone.

Natesto is a nasal gel formulation of testosterone. Endogenous androgens, testosterone and dihydrotestosterone (DHT) play an important role in the normal development and growth of the male sex organs and for maintaining the secondary sex characteristics as well.

Primary hypogonadism: could be genital or acquired. Testicular failure could result due to conditions like bilateral torsion (when a testicle rotates, twisting the spermatic cord that brings blood to scrotum), cryptorchidism (a condition in one or both of the testes fail to descend from the abdomen into the scrotum), vanishing testes syndrome, orchitis (inflammation of testes), chemotherapy, or toxic damage from alcohol or heavy metals. These men usually present with low serum testosterone levels while the follicle stimulating hormone, leuteinizing hormone are above the normal ranges.

Hypogonadotropic hypogonadism : could be congenital or acquired as well. This could be due to Idiopathic gonadotropin or leuteinizing hormone releasing hormone (LHRH) deficiency or due to the injury to pituitary-hypothalamus from tumors, radiation,  trauma etc. Men with such conditions also have low serum testosterone levels but their gonadotropins are in the normal or low ranges.

Dosage and strengths: intranasal gel 5.5mg/ actuation. 11mg ( 2 sprays I.e. 1 spray in each nostril,  TID). Total daily dose is 33mg. 

Pregnancy category : X.

Serum testosterone levels need to be monitored periodically, starting a month after initiating the treatment. When the total testosterone concentrations consistently exceeds 1050ng/dL, the therapy with Natesto should be discontinued. But if the total testosterone concentrations remain consistently below 300ng/dL, a change in treatment regimen or an alternative treatment should be considered. Natesto is not for the administration to other parts of the body. Safety and efficacy in people <18 years is not established.

Priming the pump: priming of the pump should be done prior to the first use of each dispenser. Patients should be instructed on how to prime the pump. It is done by inverting the pump and depressing it 10 times, and then discarding any small amount of the product dispensed directly into a sink and then washing the gel away thoroughly with warm water. After this the tip is to be wiped with a clean, dry tissue. If a patient gets the Natesto gel on their hands, they should wash their hands with warm water and soap immediately. 

Method or technique of administration of the dose: Patients should be instructed to follow the following steps for proper administration of Natesto. 

a. Blow the nose.

b. Remove the cap from the dispenser. 

c. Place the right index finger on the pump of the actuator and slowly advance the tip of the actuator into the left nostril upwards until their finger on the pump reaches the base of the nose.

d. Tilt the actuator so that the opening on the tip of the actuator is in contact with the lateral wall of the nostril, to ensure that the gel is applied to the nasal wall.

e. Slowly depress the pump until it stops.

f.  Remove the actuator from the nose while wiping the tip along the inside of the lateral nostril wall to fully transfer the gel.

g. Using your left index finger, repeat the steps for the right nostril.

h. Use a clean, dry tissue to wipe the tip of the actuator. 

I. Replace the cap on the dispenser. 

j. Press on the nostrils at a point just below the bridge of the nose and lightly massage.

k. Refrain from blowing the nose or sniffing for 1 hour after administration. 

Pharmacokinetics: peak plasma time is 40 minutes.

Average daily plasma concentration: is 421ng/dL.

Protein binding : protein bound in the serum to sex hormone- binding globulin (SHBG) and albumin. 

Metabolism : this drug is metabolized in liver to various 17 keto steroids through 2 different pathways. Major active metabolites formed are estradiol and dihydrotestosterone. 

Half life : of this drugs ranges from 10 – 100 minutes.

Excretion : 90% through urine as glucuronic and sulfuric acid conjugates and 6% through feces in unconjugated form. (Data from IM administration).

Use of Natesto with other nasally administered drugs (other than sympathomimetic decongestants): the interaction is unknown, so it is recommended not to administer this drug with other nasally administered drugs, other than sympathomimetic decongestants. 

Severe case of Rhinitis: if the patient experiences severe rhinitis symptoms, the drug is to be discontinued and an alternative testosterone therapy is to be used.

Contraindications: Testosterone intranasal treatment is contraindicated in men with known or suspected prostate cancer, contraindicated in men with breast carcinoma. In pregnant or breast feeding women, testosterone can cause harm to the fetus. 

Precautions : a. Patients should report if they develop any nasal signs or symptoms. 

b. It is not to be used in the patients with chronic nasal conditions. 

c. It is not to be used in patients with alterations in their nasal anatomy. 

d. Patients should be evaluated for signs and symptoms of DVT or PE.

e. It is not suitable for the use in women and children. 

f. Prostate specific antigen, lipid concentrations and hematocrit values should be monitored periodically. 

g. Some people may experience sleep apnea (in those with risk factors).

h. Exogenous administration of androgens may lead to azoospermia (no sperm count).

I. It may promote retention of sodium and water. Edema, with or without CHF may become a serious complication in patients with pre existing cardiac, hepatic or renal disease.

Drug interactions : a. Use of testosterone with corticosteroids may increase fluid retention. So it should be used with caution in patients with cardiac, hepatic or renal disease. 

b. Androgens could decrease blood glucose and therefore, may decrease insulin requirements in diabetic patients. 

c. Androgens can change anticoagulant activity, so frequent monitoring of INR (International Normalized Ratio) and prothrombin time is required in patients taking warfarin.

Overdosage: No cases of overdosing with Natesto were reported in clinical trials.

Side effects: nasopharyngitis, rhinorrhea, epistaxis, nasal discomfort, nasal scab, nasal congestion.

Post marketing reports: vascular disorders… venous thromboembolism.

Reference : the above given drug information is obtained from various journal articles, company’s website, presentations.




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