Heroin Withdrawal

The withdrawal syndrome from heroin may begin within 6 to 24 hours of discontinuation of the drug; however, this time frame can fluctuate with the degree of tolerance as well as the amount of the last consumed dose. Symptoms may include: sweating, malaise, anxiety, depression, priapism, extra sensitivity of the genitals in females, general feeling of heaviness, cramp-like pains in the limbs, yawning, tears, sleep difficulties (insomnia), cold sweats, chills, severe muscle and bone aches; nausea and vomiting, diarrhea, cramps, and fever.[31] Many users also complain of a painful condition, the so-called "itchy blood", which often results in compulsive scratching that causes bruises and sometimes ruptures the skin, leaving scabs. Abrupt termination of heroin use often causes muscle spasms in the legs (restless leg syndrome); hence "kicking" has been used as a slang term for heroin withdrawal. Discontinuation of heroin can also cause goose bumps, and this symptom is the basis for the expression "going cold turkey". The intensity of the withdrawal syndrome is variable depending on the dosage of the drug used and the frequency of use. Very severe withdrawal can be precipitated by administering an opioid antagonist to a heroin addict.

Three general approaches are available to ease the physical part of opioid withdrawal. The first is to substitute a longer-acting opioid such as methadone or buprenorphine for heroin or another short-acting opioid and then slowly taper the dose.

In the second approach, benzodiazepines such as diazepam (Valium) may temporarily ease the anxiety, muscle spasms, and insomnia associated with opioid withdrawal. The most common benzodiazepine employed is oxazepam (Serax). The use of benzodiazepines must be carefully monitored because these drugs have abuse potential, and many opioid users also use other central nervous system depressants, especially alcohol. Also, although extremely unpleasant, opioid withdrawal is seldom fatal, whereas complications related to withdrawal from benzodiazepines, barbiturates and alcohol (such as epileptic seizures, cardiac arrest, and delirium tremens) can prove hazardous and are potentially life-threatening.

Many symptoms of opioid withdrawal are due to rebound hyperactivity of the sympathetic nervous system, which can be suppressed with clonidine (Catapres), a centrally-acting alpha-2 agonist primarily used to treat hypertension. Another drug sometimes used to relieve the "restless legs" symptom of withdrawal is baclofen, a muscle relaxant. Diarrhea can likewise be treated with the peripherally active opioid drug loperamide.

Methadone is another μ-opioid agonist most often used to substitute for heroin in treatment for heroin addiction. Compared to heroin, methadone is well (but slowly) absorbed by the gastrointestinal tract and has a much longer duration of action of approximately 24 hours. Thus methadone maintenance avoids the rapid cycling between intoxication and withdrawal associated with heroin addiction. In this way, methadone has shown success as a substitute for heroin; despite bearing about the same addiction potential as heroin, it is recommended for those who have repeatedly failed to complete withdrawal or have recently relapsed. Patients properly stabilized on methadone display few subjective effects to the drug (i.e., it does not make them "high"), and are unable to obtain a "high" from other opioids except with very high doses. Methadone, since it is longer-acting, produces withdrawal symptoms that appear later than with heroin, but usually last considerably longer and can in some cases be more intense. Methadone withdrawal symptoms can potentially persist for over a month, compared to heroin where significant physical symptoms subside within 4 days.

Buprenorphine is another opiate that was recently licensed for opioid substitution treatment. As a μ-opioid receptor partial agonist, patients develop a less tolerance to it than to heroin or methadone due to a "ceiling effect." Patients are unable to obtain a "high" from other opioids during buprenorphine treatment except with very high doses. It also has less severe withdrawal symptoms than heroin when discontinued abruptly, although the duration of the withdrawal syndrome is often longer than that seen with heroin. It is usually administered sublingually (dissolved under the tongue) every 24-48 hrs. Buprenorphine is also a κ opioid receptor antagonist, which led to speculation that the drug might have additional antidepressant effects; however, no significant difference was found in symptoms of depression between patients receiving buprenorphine and those receiving methadone.

Researchers at Johns Hopkins University have been testing a sustained-release "depot" form of buprenorphine that can relieve cravings and withdrawal symptoms for up to six weeks. A sustained-release formulation would allow for easier administration and adherence to treatment, and reduce the risk of diversion or misuse.

Three opioid antagonists are available: naloxone and the longer-acting naltrexone and nalmefene. These medications block the ability of heroin, as well as the other opioids to bind to the receptor site. Recent studies have suggested that the addition of naltrexone may improve the success rate in treatment programs when combined with the traditional therapy.

Scientists at the University of Chicago undertook preliminary development of a heroin vaccine in monkeys during the 1970s, but it was abandoned. There were two main reasons for this. Firstly, when immunized monkeys had an increase in dose of x16, their antibodies became saturated and the monkey had the same effect from heroin as non-immunized monkeys. Secondly, until they reached the x16 point immunized monkeys would substitute other drugs to get a heroin-like effect. These factors suggested that immunized human users would simply either take massive quantities of heroin, or switch to other drugs.

There is also a controversial treatment for heroin addiction based on an Iboga-derived African drug, ibogaine. Many people travel abroad for ibogaine treatments that generally interrupt substance use disorders for 3-6 months or more in up to 80% of patients. Relapse may occur when the person returns home to their normal environment however, where drug seeking behavior may return in response to social and environmental cues. Ibogaine treatments are carried out in several countries including Mexico and Canada as well as, in South and Central America and Europe. Opioid withdrawal therapy is the most common use of ibogaine. Some patients find ibogaine therapy more effective when it is given several times over the course of a few months or years. A synthetic derivative of ibogaine, 18-methoxycoronaridine was specifically designed to overcome cardiac and neurotoxic effects seen in some ibogaine research but, the drug has not yet found its way into clinical research..