Complications of insertion and removal
IMPLANON should be inserted subdermally so that it is palpable after insertion. Failure to insert IMPLANON properly may go unnoticed unless the implant is palpated immediately after insertion. Deep insertions may lead to difficult or impossible removals. Failure to remove IMPLANON may result in infertility, ectopic pregnancy, or inability to stop a drug-related adverse event. Undetected failure to insert IMPLANON may lead to an unintended pregnancy.
In clinical trials, 1.0% of patients had complications at implant insertion and 1.7% had complications at implant removal. Complications expected of a minor surgical procedure, such as pain, paresthesias, bleeding, hematoma, scarring or infection, have been reported. Occasionally in post-marketing use, implant insertions have failed because the implant fell out of the needle or remained in the needle during insertion. Implant removals may be difficult because the implant is deep, not palpable, encased in fibrous tissue, or has migrated. Implants have broken during difficult removals.
Deep insertions may result in the need for a surgical procedure in an operating room in order to remove IMPLANON. Any of the possible complications of surgery may occur. When IMPLANON is inserted too deeply (intramuscular or in the fascia) this may cause neural or vascular damage. Too deep insertions have been associated with paraesthesia (due to neural damage) and migration of the implant (due to intramuscular or fascial insertion), and in rare cases with intravascular insertion. In post-marketing use there have been cases of failure to localize and remove the implant, probably due to deep insertion. There has been one case of an intravascular insertion reported post-marketing which led to inability to remove the implant.
If infection develops at the insertion site, start suitable treatment. If infection persists, remove IMPLANON. Incomplete insertions or infections may lead to expulsion.
Be alert to the possibility of an ectopic pregnancy among patients using IMPLANON who become pregnant or complain of lower abdominal pain. Although ectopic pregnancies should be uncommon among patients using IMPLANON, a pregnancy that occurs in a patient using IMPLANON may be more likely to be ectopic than a pregnancy occurring in a patient using no contraception.
Patients who use IMPLANON are likely to have changes in their vaginal bleeding patterns, which are often unpredictable. These may include changes in bleeding frequency or duration, or amenorrhea. Patients should be counseled regarding unpredictable bleeding irregularities so that they know what to expect. Abnormal bleeding should be evaluated as needed to exclude pathologic conditions or pregnancy.
In clinical trials, bleeding changes were the single most common reason for stopping treatment with IMPLANON (11.1%, or 105 of 942 patients using IMPLANON). Most patients stopped treatment with IMPLANON because of irregular bleeding (10.8%), but some stopped because of amenorrhea (0.3%). In these studies, patients using IMPLANON had an average of 17.7 days of bleeding or spotting every 90 days (based on 3315 intervals of 90 days recorded by 780 patients). The percentages of patients having 0, 1-7, 8-21, or >21 days of spotting or bleeding over a 90-day interval while using IMPLANON are shown in the following table.
% = Percentage of 90-day intervals with this pattern.
Based on 3,315 recording periods of 90 days duration in 780 women, excluding the first 90 days after implant insertion.
Interaction with anti-epileptic and other drugs
IMPLANON is not recommended for women who chronically take drugs that are potent hepatic enzyme inducers because etonogestrel levels may be substantially reduced in these women.
If follicular development occurs, atresia of the follicle is sometimes delayed, and the follicle may continue to grow beyond the size it would attain in a normal cycle. Generally, these enlarged follicles disappear spontaneously. Rarely, they can require surgery.
There have been post-marketing reports of serious thromboembolic events, including cases of pulmonary emboli (some fatal) and strokes, in patients using IMPLANON. IMPLANON should be removed in the event of a thrombosis. Consider removal of IMPLANON in case of long-term immobilization due to surgery or illness. Women with a history of thromboembolic disorders should be made aware of the possibility of a recurrence. See also warnings based on experience with combination (progestin and estrogen) oral contraceptives.