Opioids

Opioids are a class of drugs best known for their morphine-like painkilling properties. There are two basic forms of opioids: those that originate in the opium poppy (e.g., codeine, morphine, heroin) and those that have similar properties but are man-made (e.g., methadone, Demerol®). Other medications that are opioids, or combinations of opioids and other painkilling ingredients, include OxyContin®, Percocet®, Percodan® and Tylenol® 1, 2, 3 and 4.

Opioids are central nervous system depressants, which means they slow down breathing, heart rate, and gastric and brain activity. Long-term use of most opioids results in physical dependency, which can cause withdrawal symptoms if there is a sudden stop or reduction in use, or administration of an opioid antagonist (blocker) such as naloxone. Opioids can also cause feelings of euphoria (intense pleasure), which can lead to misuse and, potentially, addiction.

Methadone, a synthetic opioid, is commonly used as an effective treatment for opioid dependency. It acts on the same brain receptors as other opioids, so it blocks their effects without causing euphoria or sedation. It is also longer acting than most other opioids, and prevents craving and withdrawal symptoms.

Suboxone® is another medication available in Canada for opioid maintenance treatment. It contains buprenorphine (a semi-synthetic opioid with properties similar to those of methadone) and naloxone. Naloxone prevents buprenorphine from affecting the body if it is injected. If Suboxone is injected by someone dependent on opioids, the person will experience immediate and severe withdrawal symptoms.

Effects on general health

• Long-term use of opioids can result in depression, difficulty concentrating and sleeping, and sexual problems.
• Constipation can become a serious problem after long-term use.
• After exposure to opioid drugs for a long time, the body stops making natural painkillers. Even small pains can be severe.
• Opioids can decrease appetite, which can lead to malnutrition.
• Very high doses can cause disorientation, convulsions and hallucinations.
• Overdoses of opioids seriously reduce the heart rate, blood pressure and breathing. An opioid overdose can be fatal.
• Symptoms of withdrawal from opioids can range from mild (some anxiety, sleeplessness, cravings, sweating) to moderate (nausea, cramping, diarrhea, insomnia, tremors) to severe (agitation and pain, kicking legs, elevated temperature).

Effects on women’s health

Women are at increased risk for irregular or disrupted menstrual cycles while using opioids.

Effects during pregnancy

With proper medical supervision and assessment, most prescribed opioids can be used safely during pregnancy as long as they are used according to the prescription.

There are, however, risks associated with misuse of prescribed opioids or non-medical use of opioids. Alternating between intoxication and withdrawal can result in an unstable intrauterine environment, possibly leading to spontaneous abortion, miscarriage, premature labour, placental abruption or stillbirth. There can also be complications caused by the lifestyle and patterns of behaviour that sometimes accompany illicit opioid use.

Intravenous use increases the chance of overdosing, and is one of the main transmission routes for viruses including hepatitis C and HIV (human immunodeficiency virus). It also increases the chance of a reaction between the mother’s and fetus’s blood; for the fetus, this can lead to anemia, heart failure or even death.

People addicted to opioids may also have poor nutrition and living conditions, and may engage in high-risk activities to fund their addiction.

As with all drugs, it can be difficult to attribute a child’s health problems solely to a mother’s use of opioids because of other factors such as

• smoking
• alcohol consumption
• use of more than one drug
• lack of sleep
• general health before pregnancy
• genetics

Effects on the fetus

Opioids have not generally been found to cause malformations or birth defects in the fetus, although in some cases, they might result in a lower birth weight and decreased head circumference.

HIV, hepatitis B or hepatitis C contracted from injecting opioids can be passed from mother to baby during pregnancy

Effects on birth

Complications can occur during pregnancy due to the cycle of intoxication and withdrawal, as well as lifestyle issues associated with the misuse of opioids. These complications include

• placental abruption: premature separation of the placenta from the wall of the uterus, a potentially very serious situation for the mother and baby
• eclampsia: a condition characterized by high blood pressure and seizures in the mother which is life-threatening for her and the baby
• placental insufficiency: insufficient blood circulation in the placenta
• breech birth
• ruptured membranes
• premature labour and delivery: the baby is born before full term
• stillbirth

Babies born to women who use opioids regularly during pregnancy are sometimes born physically dependent on the drug. The withdrawal these infants experience after they are born is called neonatal abstinence syndrome (NAS). NAS usually affects the infant’s central nervous system and gastrointestinal tract. Symptoms include muscle spasms, irritability, high-pitched crying, diarrhea, disturbed sleep and feeding, vomiting, hiccups, stuffy nose, sneezing, and breathing problems. The onset and persistence of these symptoms vary, but they generally begin 48 to 72 hours after birth and typically subside in a week. These symptoms can be safely managed by a physician. NAS is not known to cause any long-term complications.

Effects on breastfeeding

When taken at therapeutic levels, most prescribed opioids are safe to take while breastfeeding, because only small amounts are excreted into the breast milk. It is still advised, however, that babies be carefully monitored for signs of excessive drowsiness.

Breastfeeding is not recommended when non-prescribed opioids are being used, because of the risks associated with a baby being exposed to fluctuating and higher than therapeutic levels of opioids.

Methadone maintenance treatment is compatible with breastfeeding regardless of the methadone dose prescribed to the mother. Use of Suboxone while breastfeeding is not recommended.

Women with some blood-borne infections, such as HIV/AIDS and tuberculosis, should not breastfeed, because there is a risk of the infections being transmitted to the baby.

Effects on long-term child development

There has been very little research on the long-term effects of intrauterine opioid exposure in people. Research that has been done has yielded inconsistent and contradictory results. The main difficulty has been in determining whether any growth deficits or developmental delays found in opioid-exposed children are caused purely by the opioid use or by other factors as noted above (such as smoking, alcohol consumption, or use of more than one drug).

Opioid maintenance treatment during pregnancy

Women dependent on opioids are advised against attempting to detoxify during pregnancy because of the potential harmful effects of withdrawal on the fetus. Studies recommend methadone maintenance as the opioid maintenance treatment of choice for pregnant women addicted to opioids. Women who are on methadone maintenance treatment have fewer complications during pregnancy and childbirth, and are healthier in general, than those using non-prescribed opioids. This is probably the result of a combination of methadone preventing cravings and withdrawals, abstinence from other opioids and injecting, easier access to medical and prenatal care, and an easing of some of the stresses related to illegal drug use.

The safety of Suboxone during pregnancy has not yet been established; therefore, its use is not recommended. Women who become pregnant or who plan to become pregnant while taking Suboxone are advised to switch to methadone during the pregnancy and while breastfeeding.