Mitigo

MITIGO ® is for use in continuous microinfusion devices and indicated only for intrathecal or epidural infusion in the management of intractable chronic pain severe enough to require an opioid analgesic and for which less invasive means of controlling pain are inadequate.

Limitations of Use

Not for single-dose intravenous, intramuscular, or subcutaneous administration due to the risk of overdose.

Not for single-dose neuraxial injection because MITIGO ® is too concentrated for accurate delivery of the smaller doses used in this setting.

MITIGO ® should not be used for an extended period of time unless the pain remains severe enough to require an opioid analgesic and for which alternative treatment options continue to be inadequate.

2.1 Important Dosage and Administration Instructions

MITIGO ® should be administered by or under the direction of a physician experienced in the techniques of epidural or intrathecal administration and familiar with the patient management problems associated with epidural or intrathecal drug administration.

• MITIGO ® should be prescribed only by healthcare professionals who are knowledgeable about the use of opioids and how to mitigate the associated risks.
• Because of the risk of delayed respiratory depression, patients should be observed in a fully equipped and staffed environment for at least 24 hours after each test dose and, as indicated, for the first several days after surgery.
• Because epidural administration has been associated with less potential for immediate or late adverse effects than intrathecal administration, the epidural route should be used whenever possible.
• For safety reasons, it is recommended that administration of MITIGO ® 200 mg/20 mL and 500 mg/20mL (10 and 25 mg/mL, respectively) by the intrathecal route be limited to the lumbar area.
• MITIGO ® 200 mg/20 mL and 500 mg/20 mL (10 and 25 mg/mL, respectively) should not be used for single-dose neuraxial injection because lower doses can be more reliably administered with the standard preparation of morphine sulfate injection, USP (0.5 and 1 mg/mL).

Candidates for neuraxial administration of MITIGO ® in a continuous microinfusion device should be hospitalized to provide for adequate patient monitoring during assessment of response to single doses of intrathecal or epidural morphine. Hospitalization should be maintained for several days after surgery involving the infusion device for additional monitoring and adjustment of daily dosage. The facility must be equipped with resuscitative equipment, oxygen, naloxone injection and other resuscitative drugs.

A period of observation appropriate to the clinical situation should follow each refill or manipulation of the drug reservoir. Before discharge, the patient and attendant(s) should receive instruction in the proper home care of the device and insertion site and in the recognition and practical treatment of an overdose of neuraxial morphine.

Familiarization with the continuous microinfusion device is essential. The desired amount of morphine should be withdrawn from the vial through a microfilter. To minimize risk from glass or other particles, the product must be filtered through a 5 μ (or smaller) microfilter before injecting into the microinfusion device. If dilution is required, 0.9% Sodium Chloride Injection is recommended.

Reservoir filling must be performed by fully trained and qualified personnel, following the directions provided by the device manufacturer. Care should be taken in selecting the proper refill frequency to prevent depletion of the reservoir, which would result in exacerbation of severe pain, onset of opioid withdrawal symptoms, and/or reflux of cerebrospinal fluid into some devices. Strict aseptic technique is required to avoid bacterial contamination and serious infection. Extreme care must be taken to ensure that the needle is properly inserted into the filling port of the device before attempting to refill the reservoir. Injecting the solution into the tissue around the device or (in the case of devices that have more than one port) attempting to inject the refill dose into the direct injection port will result in a large, clinically significant, overdosage to the patient.

Safety and Handling Instructions:

MITIGO ® is supplied in sealed vials. Accidental dermal exposure should be treated by the removal of any contaminated clothing and rinsing the affected area with water.

Inspect parenteral drug products for particulate matter before opening the amber vials and again for color after removing contents from the vial. Do not use if the solution in the unopened vial contains a precipitate which does not disappear upon shaking. After removal, do not use unless the solution is colorless or pale yellow.

MITIGO® is intended for single-dose only. Protect from light, discard any unused portion. Do not heat-sterilize.

2.2 Initial Dosage

The starting dose of MITIGO ® must be individualized, based upon in-hospital evaluation of the response to serial single-dose epidural or intrathecal bolus injections of regular morphine sulfate injection, USP 0.5 mg/mL or 1 mg/mL, with close observation for analgesic efficacy and adverse effects prior to surgery involving the continuous microinfusion device.

• Use the lowest effective dosage for the shortest duration of time consistent with individual patient treatment goals [see Warnings and Precautions ( 5)]. Because the risk of overdose increases as opioid doses increase, reserve titration to higher doses of MITIGO ® for patients in whom lower doses are insufficiently effective and in whom the expected benefits of using a higher dose opioid clearly outweigh the substantial risks.
• There is variability in the opioid analgesic dose and duration needed to adequately manage pain due both to the cause of pain and to individual patient factors. Initiate the dosing regimen for each patient individually, taking into account the patient’s underlying cause and severity of pain, prior analgesic treatment and response, and risk factors for addiction, abuse, and misuse [see Warnings and Precautions ( 5.1)].
• Respiratory depression can occur at any time during opioid therapy, especially when initiating and following dosage increases with MITIGO ®. Consider this risk when selecting an initial dose and when making dose adjustments [see Warnings and Precautions ( 5)].

2.3 Dosage for Epidural Administration

The recommended initial epidural dose in patients who are not tolerant to opioids ranges from 3.5 to 7.5 mg/day. The usual starting dose for continuous epidural infusion, based upon limited data in patients who have some degree of opioid tolerance, is 4.5 to 10 mg/day. The dose requirements may increase significantly during treatment, frequently to 20-30 mg/day. The upper daily limit for each patient must be individualized.

2.4 Dosage for Intrathecal Administration

The recommended initial lumbar intrathecal dose range in patients with no tolerance to opioids is 0.2 to 1 mg/day. The published range of doses for individuals who have some degree of opioid tolerance varies from 1 to 10 mg/day. The upper daily dosage limit for each patient must be individualized.

• Intrathecal dosage is usually 1/10 that of epidural dosage.

2.5 Titration and Maintenance of Therapy

Individually titrate MITIGO ® to a dose that provides adequate analgesia and minimizes adverse reactions. Continually reevaluate patients receiving MITIGO ® to assess the maintenance of pain control, signs and symptoms of opioid withdrawal, and other adverse reactions, as well as to reassess for the development of addiction, abuse, or misuse [see Warnings and Precautions ( 5.3, 5.16)] . Frequent communication is important among the prescriber, other members of the healthcare team, the patient, and the caregiver/family during periods of changing analgesic requirements, including initial titration.

If the level of pain increases after dosage stabilization, attempt to identify the source of the increased pain before increasing the MITIGO ® dosage. If after increasing the dosage, unacceptable opioid-related adverse reactions are observed (including an increase in pain after a dosage increase), consider reducing the dosage [see Warnings and Precautions ( 5)] . Adjust the dosage to obtain an appropriate balance between management of pain and opioid-related adverse reactions.

Limited experience with continuous intrathecal infusion of morphine has shown that the daily doses have to be increased over time. Although the rate of increase, over time, in the dose required to sustain analgesia is highly variable, an estimate of the expected rate of increase is shown in the following Figure.

Doses above 20 mg/day should be employed with caution since they may be associated with a higher likelihood of serious side effects [see Warnings and Precautions ( 5.2, 5.7) and Adverse Reactions ( 6)] .
If unacceptable opioid-related adverse reactions are observed, consider reducing the dosage. Adjust the dosage to obtain an appropriate balance between management of pain and opioidrelated adverse reactions.

2.6 Safe Reduction or Discontinuation of MITIGO ®

When a patient who has been taking MITIGO ® regularly and may be physically dependent or no longer requires therapy with MITIGO ®, taper the dose gradually while monitoring carefully for signs and symptoms of withdrawal. If the patient develops these signs or symptoms, raise the dose to the previous level and taper more slowly, either by increasing the interval between decreases, decreasing the amount of change in dose, or both. Do not stop MITIGO ® abruptly in a physically-dependent patient [see Warnings and Precautions ( 5.15), Drug Abuse and Dependence ( 9.3)].

3 DOSAGE FORMS AND STRENGTHS

Injection: 200 mg per 20 mL (10 mg/mL) Preservative-free amber glass single-dose vials

Injection: 500 mg per 20 mL (25 mg/mL) Preservative-free amber glass single-dose vials

8.1 Pregnancy

Risk Summary

Use of opioid analgesics for an extended period of time during pregnancy may cause neonatal opioid withdrawal syndrome [see Warnings and Precautions ( 5.5)] . Available data with MITIGO ® in pregnant women are insufficient to inform a drug-associated risk for major birth defects and miscarriage. There are adverse outcomes reported with fetal exposure to opioid analgesics (see Clinical Considerations). Published studies with morphine use during pregnancy have not reported a clear association with morphine and major birth defects [see Human Data]. In published animal reproduction studies, morphine administered subcutaneously during the early gestational period produced neural tube defects (i.e., exencephaly and cranioschisis) at 5 and 16 times the human daily dose of 60 mg based on body surface area (HDD) in hamsters and mice, respectively, lower fetal body weight and increased incidence of abortion at 0.4 times the HDD in the rabbit, growth retardation at 6 times the HDD in the rat, and axial skeletal fusion and cryptorchidism at 16 times the HDD in the mouse. Administration of morphine sulfate to pregnant rats during organogenesis and through lactation resulted in cyanosis, hypothermia, decreased brain weights, pup mortality, decreased pup body weights, and adverse effects on reproductive tissues at 3-4 times the HDD; and long-term neurochemical changes in the brain of offspring which correlate with altered behavioral responses that persist through adulthood at exposures comparable to and less than the HDD [see Animal Data]. Based on animal data, advise pregnant women of the potential risk to a fetus.

The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Clinical Considerations

Fetal/Neonatal Adverse Reactions

Use of opioid analgesics for an extended period of time during pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth.

Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, and failure to gain weight. The onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of the drug by the newborn. Observe newborns for symptoms of neonatal opioid withdrawal syndrome and manage accordingly [see Warnings and Precautions ( 5.5].

Labor or Delivery

MITIGO ® 200 mg/20 mL and 500 mg/20 mL (10 and 25 mg/mL, respectively) are too highly concentrated for routine use in obstetric neuraxial analgesia. Opioids, including intravenously,epidurally, and intrathecally administered morphine, readily cross the placenta and may produce respiratory depression and psycho-physiologic effects in neonates. An opioid antagonist, such as naloxone, and resuscitative equipment must be available for reversal of opioid-induced respiratory depression in the neonate. MITIGO ® is not recommended for use in pregnant women during or immediately prior to labor, when other analgesic techniques are more appropriate.Opioid analgesics, including MITIGO ®, can prolong labor through actions which temporarily reduce the strength, duration, and frequency of uterine contractions. However, this effect is not consistent and may be offset by an increased rate of cervical dilation, which tends to shorten labor. Monitor neonates exposed to opioid analgesics during labor for signs of excess sedation and respiratory depression.

Data

Human Data

The results from a population-based prospective cohort, including 70 women exposed to morphine during the first trimester of pregnancy and 448 women exposed to morphine at any time during pregnancy, indicate no increased risk for congenital malformations. However, these studies cannot definitely establish the absence of any risk because of methodological limitations, including small sample size and non-randomized study design.

Animal Data

Formal reproductive and developmental toxicology studies for morphine have not been conducted. Exposure margins for the following published study reports are based on human daily dose of 60 mg morphine using a body surface area comparison (HDD).

Neural tube defects (exencephaly and cranioschisis) were noted following subcutaneous administration of morphine sulfate (35-322 mg/kg) on Gestation Day 8 to pregnant hamsters (4.7 to 43.5 times the HDD). A no adverse effect level was not defined in this study and the findings cannot be clearly attributed to maternal toxicity. Neural tube defects (exencephaly), axial skeletal fusions, and cryptorchidism were reported following a single subcutaneous (SC) injection of morphine sulfate to pregnant mice (100-500 mg/kg) on Gestation Day 8 or 9 at 200 mg/kg or greater (16 times the HDD) and fetal resorption at 400 mg/kg or higher (32 times the HDD). No adverse effects were noted following 100 mg/kg morphine in this model (8 times the HDD). In one study, following continuous subcutaneous infusion of doses greater than or equal to 2.72 mg/kg to mice (0.2 times the HDD), exencephaly, hydronephrosis, intestinal hemorrhage, split supraoccipital, malformed sternebrae, and malformed xiphoid were noted. The effects were reduced with increasing daily dose; possibly due to rapid induction of tolerance under these infusion conditions. The clinical significance of this report is not clear.

Decreased fetal weights were observed in pregnant rats treated with 20 mg/kg/day morphine sulfate (3.2 times the HDD) from Gestation Day 7 to 9. There was no evidence of malformations despite maternal toxicity (10% mortality). In a second rat study, decreased fetal weight and increased incidences of growth retardation were noted at 35 mg/kg/day (5.7 times the HDD) and there was a reduced number of fetuses at 70 mg/kg/day (11.4 times the HDD) when pregnant rats were treated with 10, 35, or 70 mg/kg/day morphine sulfate via continuous infusion from Gestation Day 5 to 20. There was no evidence of fetal malformations or maternal toxicity.

An increased incidence of abortion was noted in a study in which pregnant rabbits were treated with 2.5 (0.8 times the HDD) to 10 mg/kg morphine sulfate via subcutaneous injection from Gestation Day 6 to 10. In a second study, decreased fetal body weights were reported following treatment of pregnant rabbits with increasing doses of morphine (10-50 mg/kg/day) during the pre-mating period and 50 mg/kg/day (16 times the HDD) throughout the gestation period. No overt malformations were reported in either publication; although only limited endpoints were evaluated.

In published studies in rats, exposure to morphine during gestation and/or lactation periods is associated with: decreased pup viability at 12.5 mg/kg/day or greater (2 times the HDD); decreased pup body weights at 15 mg/kg/day or greater (2.4 times the HDD); decreased litter size, decreased absolute brain and cerebellar weights, cyanosis, and hypothermia at 20 mg/kg/day (3.2 times the HDD); alteration of behavioral responses (play, social-interaction) at 1 mg/kg/day or greater (0.2 times the HDD); alteration of maternal behaviors (e.g., decreased nursing and pup retrievals) in mice at 1 mg/kg or higher (0.08 times the HDD) and rats at 1.5 mg/kg/day or higher (0.2 times the HDD); and a host of behavioral abnormalities in the offspring of rats, including altered responsiveness to opioids at 4 mg/kg/day (0.7 times the HDD) or greater.

Fetal and/or postnatal exposure to morphine in mice and rats has been shown to result in morphological changes in fetal and neonatal brain and neuronal cell loss, alteration of a number of neurotransmitter and neuromodulator systems, including opioid and nonopioid systems, and impairment in various learning and memory tests that appear to persist into adulthood. These studies were conducted with morphine treatment usually in the range of 4 to 20 mg/kg/day (0.7 to 3.2 times the HDD).

Additionally, delayed sexual maturation and decreased sexual behaviors in female offspring at 20 mg/kg/day (3.2 times the HDD), and decreased plasma and testicular levels of luteinizing hormone and testosterone, decreased testes weights, seminiferous tubule shrinkage, germinal cell aplasia, and decreased spermatogenesis in male offspring were also observed at 20 mg/kg/day (3.2 times the HDD). Decreased litter size and viability were observed in the offspring of male rats that were intraperitoneally administered morphine sulfate for 1 day prior to mating at 25 mg/kg/day (4.1 times the HDD) and mated to untreated females. Decreased viability and body weight and/or movement deficits in both first and second generation offspring were reported when male mice were treated for 5 days with escalating doses of 120 to 240 mg/kg/day morphine sulfate (9.7 to 19.5 times the HDD) or when female mice treated with escalating doses of 60 to 240 mg/kg/day (4.9 to 19.5 times the HDD) followed by a 5- day treatment-free recovery period prior to mating. Similar multigenerational findings were also seen in female rats pre-gestationally treated with escalating doses of 10 to 22 mg/kg/day morphine (1.6 to 3.6 times the HDD).

8.2 Lactation

Risk Summary

Morphine is present in breast milk. Published lactation studies report variable concentrations of morphine in breast milk with administration of immediate-release morphine to nursing mothers in the early postpartum period with a milk-to-plasma morphine AUC ratio of 2.5:1 measured in one lactation study. However, there is insufficient information to determine the effects of morphine on the breastfed infant and the effects of morphine on milk production. Lactation studies have not been conducted with MITIGO ®, and no information is available on the effects of the drug on the breastfed infant or the effects of the drug on milk production.

The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for MITIGO ® and any potential adverse effects on the breastfed infant from MITIGO ® or from the underlying maternal condition.

Clinical Considerations

Monitor infants exposed to MITIGO ® through breast milk for excess sedation and respiratory depression. Withdrawal symptoms can occur in breastfed infants when maternal administration of morphine is stopped, or when breastfeeding is stopped.

8.3 Females and Males of Reproductive Potential

Infertility

Use of opioids for an extended period of time may cause reduced fertility in females and males of reproductive potential. It is not known whether these effects on fertility are reversible [see Adverse Reactions ( 6), Clinical Pharmacology ( 12.2].

In published animal studies, morphine administration adversely effected fertility and reproductive endpoints in male rats and prolonged estrus cycle in female rats [see Nonclinical Toxicology ( 13)].

8.4 Pediatric Use

Adequate studies to establish the safety and effectiveness of spinal morphine in pediatric patients have not been performed, and usage in this population is not recommended.

8.5 Geriatric Use

Elderly patients (aged 65 years or older) may have increased sensitivity to MITIGO ®. In general, use caution when selecting a dosage for an elderly patient, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other drug therapy.

Respiratory depression is the chief risk for elderly patients treated with opioids, and has occurred after large initial doses were administered to patients who were not opioidtolerant or when opioids were co-administered with other agents that depress respiration. Titrate the dosage of MITIGO ® slowly in geriatric patients and monitor closely for signs of central nervous system and respiratory depression [see Warnings and Precautions ( 5.8)].

The pharmacodynamic effects of neuraxial morphine in the elderly are more variable than in the younger population. Patients will vary widely in the effective initial dose, rate of development of tolerance and the frequency and magnitude of associated adverse effects as the dose is increased. Initial doses should be based on careful clinical observation following “test doses”, after making due allowances for the effects of the patient’s age and infirmity on his/her ability to clear the drug, particularly in patients receiving epidural morphine.

Morphine is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

8.6 Hepatic or Renal Impairment

The elimination half-life of morphine may be prolonged in patients with reduced metabolic rates and with hepatic and/or renal dysfunction. Hence, care should be exercised in administering MITIGO ® epidurally to patients with these conditions. High blood morphine levels, due to reduced clearance, may take several days to develop.