AndroGel Variable Absorption That Doesn't Resolve: Causes, Management, and When to Switch

What the delivery data show

A multicenter study of 227 hypogonadal men compared daily 50 mg and 100 mg doses of a 1% hydroalcoholic testosterone gel with a testosterone patch [1]. About 9 to 14% of the testosterone applied as gel was bioavailable, and serum testosterone rose into the normal adult male range on day one. The researchers reported that an earlier study had found steady state 48 to 72 hours after the first application [1]. Pharmacokinetic parameters for total and free testosterone were very similar on days 30, 90 and 180 in every treatment group [1].

Raising the dose from 50 mg to 75 mg daily did not significantly increase average serum testosterone, while lowering 100 mg to 75 mg brought most men into the normal range [1].

What the Teva gel 1% label says, and what it is not

The Teva testosterone gel 1% prescribing information is for a 1% gel product other than AndroGel [2]. It requires low morning serum testosterone on at least two separate days before treatment begins, starts at 50 mg once daily in the morning, and adjusts using 50, 75 or 100 mg on the basis of total serum testosterone during treatment [2]. Its own text notes that topical testosterone products may differ in dose, strength and application instructions, producing different systemic exposure [2]. Its dosing and safety figures are therefore not AndroGel's.

What the label lists for safety monitoring

The Teva label calls for a hematocrit check before treatment, again 3 to 6 months after starting, and then annually, and notes that increased red cell mass may raise thromboembolic risk [2]. Blood pressure is measured periodically, and the gel is not recommended in men with uncontrolled hypertension; in an ambulatory study, mean 24-hour blood pressure rose 1.9/1.3 mm Hg by week 16 [2]. FDA says its required blood pressure studies confirmed increases with testosterone products across the class [4]. Venous thromboembolism has been reported with testosterone products, and the label reports a rate of 1.7% versus 1.2% on placebo in TRAVERSE [2].

If a formulation change is considered

No blood-test cutoff for switching was identified. One measurable difference by route is hematocrit: across 29 placebo-controlled trials in 3,393 men, mean hematocrit rose 3.0% with gels and 4.0% with intramuscular enanthate or cypionate, and the difference between those two was not statistically significant [3]. A retrospective review of 178 men followed for three years found hematocrit above 50% in 12.8% of gel users and 66.7% of injection users, though the injection group was younger, started with a higher hematocrit, and the study was not randomized [6]. The Endocrine Society recommends monitoring symptoms, serum testosterone, hematocrit and prostate cancer risk during the first year of therapy [5], and FDA lists approved testosterone formulations as topical gel, transdermal patch, buccal system and injection [7].