Methadone Side Effects

treatment for opiate abuse

Methadone is a medication maintenance therapy that is used to treat opiate addiction.

Methadone, a well-known treatment for heroin and prescription pain pill addictions, offers a wide range benefits to people who need help overcoming opiate addiction. While research within the addiction field has come a long way towards developing effective drug treatment approaches, methadone side effects still make it difficult for some people to remain in treatment.

As a medication therapy, the effects of methadone target certain chemical processes brain, much like addictive opiate drugs do. This similarity with other opiate drugs gives rise to many of the same problems that cause addiction. Methadone also has long-acting effects that further increase the risk of experiencing methadone side effects.

People with long histories of opiate addiction, more oftentimes than not, develop other medical and psychological conditions that may alter the effects of methadone. When this happens, methadone side effects can actually increase in intensity.

Ultimately, keeping people engaged in the treatment process becomes all the more imperative considering the risks they face when quitting or leaving methadone treatment. As the overall effects of methadone can both help and hinder a person’s recovery process, each person must decide whether the good outweighs the bad or vice versa.

Methadone Treatment

Opiate drugs as a whole carry strong analgesic properties that easily slow the body’s central nervous system processes. According to the National Highway Safety Administration, methadone is also an opiate drug, though synthetically made. In effect, methadone produces many of the same effects as other opiate drugs, though its addiction potential remains considerably lower than other opiates.

Methadone’s ability to mimic the effects of other opiates without being addictive makes for a highly effective opiate addiction treatment approach. The effects of methadone combined with ongoing behavioral therapy treatments provide recovering addicts with the tools they need to live a drug-free life.

Compared to other addictive opiate drugs, methadone produces a slow-acting effect that only requires a daily dose as opposed to the multiple “fixes” addicts typically ingest throughout the day. This slow-acting mechanism can produce methadone side effects for some people. Side effects may take the form of –

  • Lightheadedness
  • Drowsiness
  • Dizziness
  • Stupor-state
  • Slow reflexes

These types of methadone side effects may develop when dosage levels are set too high. Daily dosage level amounts ultimately determine how effective methadone treatment will be for any one person. Too high a dosage will produce unwanted sedating effects that can potentially impair a person’s ability to carry out daily living activities. Too low a dosage leaves a person at risk of experiencing drug cravings and withdrawal effects.

Tolerance, Dependence and Withdrawal Effects

As any opiate addict well knows, the body tends to crave larger “fixes” the longer a person continues to use. Even though it’s synthetically made, methadone still retains many of the same properties of opiate drugs. This means, people who remain in treatment for long periods of time will likely develop a tolerance to the effects of methadone. This process runs counter to the drug’s intended therapeutic effects, making increasing tolerance levels another methadone side effect.

As tolerance levels increase, the body, in turn, becomes more and more dependent on methadone’s effects. For this reason, dosage level amounts may require adjustment from time to time for the duration of the methadone treatment process. This methadone side effect, in particular can create additional problems, especially in cases where a person has a long history of opiate abuse.

Unless the necessary dosage adjustments are made, a person will likely experience the withdrawal effects of methadone. Methadone withdrawal effects may include –

  • Nausea
  • Diarrhea
  • Muscle aches
  • Irritability
  • Chills

With withdrawal effects and drug cravings being the two main challenges recovering addicts face, this methadone side effect can quickly place a person at high risk of relapse.

Drug Interactions

The therapeutic effects of methadone rely on the rate at which the body metabolizes the drug. Anything capable of altering a person’s metabolism rates can potentially offset the intended effects of methadone. People who take medications for medical conditions or psychological disorders may experience methadone drug interactions.

Methadone side effects, such as slowed reflexes, dizziness and lightheadedness can develop in cases where a person is taking another type of central nervous system depressant. Likewise, methadone side effects can take the form of withdrawal symptoms in cases where a person takes medications that stimulate the body’s central nervous system.

Drugs likely to induce methadone side effects include –

CNS Depressants

  • Tranquilizers
  • Tricylic antidepressants
  • Alcohol
  • Hypnotics

CNS Stimulants

  • Pentazocine
  • Buprenorphine
  • Butorphanol
  • Nalbuphine


Compared to other opiate drugs, methadone has a longer half-life in terms of how long the drug stays in the body. According to the National Library of Medicine, methadone’s half-life duration contributes to its slow acting therapeutic effects.

Unfortunately, methadone’s half-life of eight to 59 hours runs considerably longer than its therapeutic effects, which only run from four to eight hours. This imbalance in the drug’s effects can cause considerable problems for someone just starting out on methadone treatments. In this case, toxic levels of methadone can build up in a person’s system before he or she experiences the drug’s therapeutic benefits.

As a methadone side effect, the risk of toxicity is especially high at the start of methadone treatment and in many cases can lead to death. For this reason, prescribing physicians must keep a close watch on the effects of methadone to prevent toxic levels from developing.

Overdose Risks

The risk of overdosing while receiving methadone treatment is no doubt the worst of all methadone side effects. During the treatment process, the long acting effects of methadone place patients at risk of overdose each time a dosage adjustment is made. In general, a change in dosage amounts can take anywhere from three to five days before any therapeutic effects become apparent. Dosage increases made before the three-day mark can potentially place patients at risk of overdose.

As with other opiate drugs, the risk of overdose increases when combining methadone with other central nervous system depressant drugs. Consequently, people who attempt to use other opiates while taking methadone place themselves at considerable risk of overdose.

Methadone side effects, in general, can create real problems for people in treatment and eventually cause a person to discontinue treatment altogether. Likewise, the effects of methadone can be deadly in cases where a person attempts to abuse the drug or unknowingly takes medications that alter methadone’s intended effects.