Methadone Addiction Help-Line
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Methadone Effects

Methadone's effects are less powerful than heroin, though it offers a similar, though less intense, absence of pain combined with euphoric qualities. The combined methadone effects are a sense of well being, feeling warm, and content, drowsy and untroubled. Physically, the pupils of the eye become smaller, body temperature drops, and blood pressure and pulse slow down. Methadone may also affect a person’s ability to drive a car or operate heavy machinery. Long term effects of methadone include increased sweating and constipation. Both men and women may experience sexual problems and a woman’s menstrual cycle may be disrupted. At higher doses, the user may become heavily sedated, be sleepy, unable to talk, and appear to fall asleep for a few minutes at a time Users often experience nausea or vomiting on the first occasions that they use methadone, or when returning to use after a period of abstinence. Side effects include suppression of the cough reflex, more shallow breathing and a slowing of the pulse rate. Some users experience intense, allergy-like itchiness.

Methadone does not produce only a single desired effect, the ease of withdrawal from heroin. Patients on methadone maintenance report a wide range of methadone effects. A long list of methadone's effects has be compiled and are presented below. Some of these methadone effects are easily mistaken as withdrawal symptoms or as other medical conditions. Methadone is not an innocent substance; 'one's methadone maintenance dose is another's poison. A regular user of opiates develops a certain tolerance. Therefore, it is possible that a tolerant person can function normally with dosages which can be fatal to a non-tolerant person.

Like all opiates, methadone crosses the placenta to the unborn child. Many of the babies born to methadone-dependent mothers go through withdrawal at birth. Their symptoms vary in length and strength. These can be successfully treated while the baby is still in hospital. Overall, women using methadone have fewer problems during their pregnancy than those who continue to use heroin. As small amounts of methadone may be passed on through breast milk, mothers that are on a methadone program are often encouraged to breastfeed in order to help ease the baby's withdrawal from methadone.

Methadone Effects

  • Sweating is often increased, especially at night.
  • Constipation is quite common. Drink plenty of water and eat more fruit,
    vegetables, wholemeal and bran products.
  • Aching muscles and joints may be experienced, even when the dose of
    methadone is adequate. Some people report rheumatism-type aches and
    pains at various times.
  • Lowered sex drive is experienced with the use of any opioid, including
    methadone and heroin. However, this may settle down.
  • Skin rashes and itching are experienced by some people.
  • Sedation (for example, drowsiness, especially soon after a dose).
  • Fluid retention causing swelling or ‘puffiness’ of the hands or feet.
  • Loss of appetite, nausea and vomiting may occur.
  • Abdominal pain (cramps) may occur.
  • Tooth decay Methadone, like all opioids, reduces production of saliva.
    Saliva contains antibacterial agents which help prevent deterioration of teeth
    and gums. Poor or irregular diet and inadequate dental care also contribute
    to tooth decay. Regular brushing and chewing sugar-free gum can prevent
    tooth decay.
  • Changes to periods (menstruation) Many women have irregular periods
    when they use heroin or other opiates. For some women, their menstrual cycle
    returns to normal during methadone treatment, whereas others continue to have
    irregular periods while on methadone. When starting a methadone program,
    it is important to think about contraception, as you may start having periods
    again, and be at risk of getting pregnant.

Other Potential Complications Due to Methadone's Effects Include:

  • runny nose, sneezing
  • abdominal cramps
  • feeling physically weak
  • loss of appetite
  • tremors
  • muscle spasm and jerking
  • goose bumps
  • tears
  • nausea/vomiting
  • yawning
  • diarrhea
  • back and joint aches
  • high temperature but feeling cold
  • sweating
  • irritability/aggression/feelings of uneasiness
  • difficulty sleeping and
  • cravings for the drug
  • drowsiness/nodding off
  • nausea/vomiting
  • shallow breathing
  • pinpoint pupils
  • below normal drop in body temperature
  • slow blood pulse, lowered blood pressure
  • heart palpitations
  • dizziness
  • problems with sexual functioning and
  • poor blood circulation
  • sweating (clients should drink at least two liters of water per day to avoid dehydration)
  • constipation
  • aching muscles and joints
  • lowered sex drive
  • skin rashes and itching
  • sedation
  • fluid retention
  • loss of appetite, nausea/vomiting
  • abdominal cramps
  • tooth decay
  • irregular periods



  • Drug Facts
  • Many former heroin users have claimed that the horrors of heroin withdrawal were far less painful and difficult than withdrawal from methadone.
  • As long as an individual is receiving methadone treatment they are still addicted to opioids.
  • Methadone was initially used as a painkiller by the Germans during World War II.
  • Methadone Maintenance is not a cure for heroin or opiate addiction.