Testogel

Generic Name: Testosterone
Product Name: Testogel

Indication

Testogel is a medication used for testosterone replacement therapy in men with a confirmed diagnosis of hypogonadism. In order to be diagnosed with hypogonadism, a man must exhibit both clinical symptoms (e.g. lack of body hair and genital underdevelopment) and evidence from laboratory tests (blood testosterone levels) of testosterone deficiency.

Action

The active ingredient in Testogel is testosterone. Testosterone gel, when applied to the skin, increases the total amount of testosterone in the blood. The applied testosterone performs the same functions as the testosterone produced naturally by the body.

Testosterone’s primary functions are development of the male genitals and development of secondary sex characteristics (e.g. regulation of the male sex drive, body fat distribution, hair growth). Testosterone also plays a role in protein synthesis and regulating the amount of nitrogen, sodium, potassium, chloride, phosphate and water in urine.

Dose advice

Dose information

Testogel is a clear, colourless gel containing 1% of the active ingredient testosterone. It is packaged in 2.5 g or 5 g sachets. Most men will be prescribed a daily dose of 5 g Testogel (50 mg testosterone) when they begin treatment. Men with kidney or liver disorders may require lower doses.

A man’s response to treatment with 5 g Testogel daily will be assessed by measuring blood testosterone and evaluating his clinical symptoms of testosterone deficiency. Based on this information, the doctor may adjust the daily Testogel dose. The daily dose may be increased, first to 7.5 g daily, and then to a maximum of 10 g if the response to treatment remains inadequate.

Men using Testogel should apply the gel themselves at approximately the same time each day. Other people should not apply the gel, as they will be exposed to the testosterone in the medication. Testogel should be applied only to clean, dry, healthy skin. It should not be administered to genital skin, as skin irritation may occur due to the medication’s high alcohol content. The recommended sites for administration are:

• Shoulder;
• Arm; or
• Abdomen.

Testogel should be administered immediately after the sachet is opened. The entire contents of the sachet is removed and spread gently over the skin of the administration site (arm, shoulder or abdomen), so that it forms a thin layer. Testogel should not be rubbed into the skin. A period of 3–5 minutes should be allowed for the Testogel to dry before getting dressed. Hands should be washed thoroughly with soap and water following administration.

Testogel is administered transdermally (via the skin) and there is the potential for testosterone transfer to occur if the administration site of a Testogel user comes into contact with another person’s skin (e.g. a female sexual partner or a child). In cases of repeat testosterone transfer from contact with the administration site, there is potential for a range of adverse effects in females, including excessive body hair growth and irregularities in the menstrual cycle. Testogel users should be aware of the risks of potential testosterone transfer and how to avoid it.

To reduce the risk of testosterone transfer through skin contact, users should:

• Apply Testogel themselves;
• Wash hands thoroughly with soap and water after applying Testogel;
• Cover the administration site with clothing immediately after the gel has dried, and for six hours after administration to avoid skin-to-skin contact;
• Take a shower before any skin-to-skin contact occurs (e.g. during sexual activity), though not within six hours of Testogel administration as this may reduce the amount of testosterone absorbed from the gel.

If another individual’s skin inadvertently comes into contact with the Testogel administration site, they should:

• Wash the contact site immediately using soap and water;
• Report symptoms of excessive testosterone exposure (e.g. hair growth, menstrual cycle irregularities) to a medical professional.

Men using Testogel who have pregnanct or lactating partners must take particular care to avoid contact between their partner’s skin and the Testogel administration site, as such exposure has the potential to adversely affect the foetus or infant.

Men receiving Testogel therapy should seek medical advice immediately if they develop symptoms of oedema, as men who develop these symptoms should not continue with Testogel therapy.

Drug interactions

Testogel is known to interact with some other medications. It may be necessary for the medication dose to be adjusted to account for these interactions. Men should inform their doctor if they are using any of the following medications:

• Oral anti-coagulants (blood thinning medications): Monitoring of blood coagulation and adjustment of the anti-coagulant dose may be necessary;
• Corticosteroids or adrenocorticotropic hormones: These medications increase the risk of oedema, particularly in men with existing cardiac, renal or hepatic disease;
• Oxyphenbutazone: Administering Testogel at the same time as medications containing oxyphenbutazone may lead to excessive levels of oxyphenbutazone in the blood;
• Insulin therapy: Testosterone therapy may decrease serum glucose levels, requiring the dose of insulin to be reduced;
• Bupropion: Administration of Testogel at the same time as bupropion increases the risk of seizures;
• Cyclosporin : Administration of Testogel at the same time as cyclosporin may increase cyclosporin concentrations in the blood, causing toxicity to the kidneys;
• Substances that effect liver function: Including herbal preparations such as eucalyptus, comfrey and valerian.

Contraindications

Testogel should not be used by women or by males < 18 years of age.

Testogel should not be used by men with certain conditions. Tell your doctor if you have:

• Prostate or breast cancer;
• Allergy to any of the medication’s components.

Precautions

Testogel is only prescribed to men with a definitive diagnosis of male hypogonadism, based on both clinical symptoms and biochemical evidence of testosterone deficiency. Doctors do not prescribe Testogel as a treatment for for infertility or erectile dysfunction. Because testosterone has a virilising effect (causes the development of male characteristics such as facial hair and a deep voice), Testogel must not be used by women.

Currently, there is not enough evidence to determine the most appropriate blood testosterone levels in ageing men. Testosterone replacement therapy is not typically recommended for older males with naturally declining testosterone levels.

Testogel should not be used by men with prostate cancer. To assess for prostate cancer, the doctor will perform a digital rectal examination and PSA test. These tests are conducted because testosterone medications may accelerate the growth of cancers of the prostate. Regular assessments will be done to identify any prostate cancers that occur during treatment. Most patients will require annual assessment. However, those with risk factors for prostate cancer (including older age or family history of prostate cancer) will require assessment twice a year.

A doctor prescribing Testogel will monitor blood concentrations of haematocrit and haemoglobin. These tests are undertaken to identify polycythaemia, a condition characterised by an excessive red blood cell concentration. Polycytheamia occurs as a side effect of testosterone replacement therapy in some individuals. Testosterone replacement therapy may also affect a man’s liver function and blood lipid profile, so the doctor is also likely to assess these through blood tests.

Certain conditions require special consideration before Testogel use. Tell your doctor if you have:

• Severe cardiac, renal or hepatic insufficiency: Testogel treatment may cause oedema, with or without congestive heart failure;
• Symptoms of excessive androgen exposure (Irritability, nervousness, weight gain, and/or prolonged or frequent erections) while receiving treatment: Dose requires adjustment;
• Administration site reactions;
• Ischaemic heart disease;
• Hypertension: Testosterone administration may result in raised blood pressure, exacerbating hypertension;
• Epilepsy: Testogel treatment may worsen epilepsy;
• Migraines: Migraines may be aggravated by Testogel;
• Sleep apnoea (and particularly those with co-existing risk factors for sleep apnoea such as obesity and chronic respiratory disease): Testosterone replacement therapy is associated with an increased risk of this condition;
• Insulin therapy: Effective testosterone therapy is associated with increased insulin sensitivity, which may require insulin dose adjustment;
• Professional athletes: Testosterone contained in Testogel may lead to positive doping tests;
• Hypercalcaemia due to bone metastasis; and
• Severe alcohol dependence, substance abuse or psychiatric disorders: These conditions may prevent men following safety instructions to prevent testosterone transfer to sexual partners and other contacts.

Use in pregnancy

Testogel is a Pregnancy Category D medication. Women should not use Testogel. Exposure to testosterone during pregnancy is likely to lead to the over-expression of male characteristics in female foetuses.

Men receiving Testogel therapy should be particularly cautious to avoid the Testogel administration site coming into contact with the skin of a pregnant woman, as such contact carries the potential for skin-to-skin testosterone transfer.

Use in lactation

Testogel should not be used by breastfeeding women. Men with breastfeeding partners who use Testogel must take particular caution to avoid contact between the Testogel administration site and a breastfeeding woman’s skin. In the event of inadvertent contact, the woman should wash the exposed area of skin with soap and water as soon as possible.

Schedule

Testogel is a Schedule 4 medication.¹

Common side effects

All medicines have side effects. Most commonly the side effects are minor; however, some can be more serious. Usually the benefits of taking a medication outweigh the associated side effects. Your doctor would have considered these side effects before starting you on Testogel.

Common side effects are those that occur in more than 1% of people given Testogel. These include:

• Headache;
• Polycythaemia;
• Increased lipids in the blood;
• Disorders of the prostate;
• Breast growth;
• Breast pain;
• Dizziness;
• Pins and needles sensation;
• Memory loss;
• Hypersensitivity to touch;
• Mood disorders;
• High blood pressure;
• Diarrhoea;
• Hair loss;
• Skin irritation and dry skin at site of application (due to the alcohol content of the gel solution);
• Urticaria.

Rare side effects are those that occur in 0.01–0.1% of people given Testogel. These include:

• Hepatic neoplasms (the growth of malignant or benign tumours in the liver).

Adverse events that have been reported in clinical trials of other testosterone preparations and which are likely side effects of Testogel administration include:

• Changes to the prostate;
• Progression of undetected prostate cancer;
• Urinary retention;
• Skin irritation;
• Increased blood flow in the arteries;
• Nausea;
• Cholestatic jaundice;
• Changes in liver function test results;
• Increased libido;
• Depression;
• Nervousness;
• Muscle pain;
• During high prolonged treatment:
  • Changes in electrolyte concentration;
  • Reduced sperm output; and
  • Persistent or prolonged erection.

If you experience any of the listed side effects, or any other symptoms that appear abnormal or unusual, please tell your doctor.

References:

1. Product Information: Testogel. Pymble, NSW: Bayer Australia Limited; 28 January 2011.
2. Gould DC, Petty R, Jacobs HS. For and against: The male menopause – does it exist? BMJ. 2000;320(7238):858-61. [Abstract | Full text]

For further information talk to your doctor.