Methadone in the Treatment of Narcotic Addiction. Chapter 3

We need to establish a rapport with our patient before a decision for methadone treatment can be made. Many drug users have had negative experiences with doctors. The initial therapeutic relationship will be helped if we are familiar with the vernacular. Some street terms have variable meanings so clarification is essential if any doubt exists. (See Glossary)

A complete medical and social history needs to be documented. The first presentation, however, may not be the best time to take a full psychosocial history. While important, this is only occasionally of relevance in deciding upon methadone treatment.

The outcome of previous treatment episodes should be noted. The age of first opioid use and subsequent habituation may be years apart. The patient's use of other illicit drugs, tobacco, alcohol and prescribed medication should also be noted. Enquiries should also be made concerning family history, allergies, previous operations and illnesses. Many patients have a first order relative with chemical dependency.

Our patients cannot be treated in isolation, and their home life is an important factor. Methadone treatment is nearly always unsatisfactory where other members of the patient's household continue to use illicit drugs. There has generally been an inter-dependent drug-using group and when one member goes into treatment, the others are affected in several ways. Sometimes patients have to move residence, allowing different members of the household to go their separate ways.

An important prerequisite for successful methadone treatment is its accessibility. Both office and dispensary must be located near the patient's home or work and the hours of opening must be convenient for the patient's lifestyle. Flexible schedules should be available for changed circumstances such as work, study and family responsibilities. Patients should usually attend the nearest dispensary, be it a hospital, clinic or community pharmacy. As in all other branches of medical practice, patients should retain their choice of doctor and dispensary. To maintain their privacy, some patients will request a dispensary a little removed from home.

PHYSICAL EXAMINATION AND ASSESSMENT

It is important to document the patient's physical findings when commencing treatment. Physical examination is particularly important in drug and alcohol practice, where the initial history may be unreliable. Much can be gleaned from observation of the patient's eyes, skin and mental state. Many details of the history can be confirmed by examination but recent drug use should always be corroborated by urine testing.

The patient's mental state and venipuncture sites may be observed during the history taking. Although most addicts seeking treatment will display venipunctures on the backs of the hands or in the cubital fossae, a proportion smoke, snort or swallow their drug. In some areas where needles are not available, as many as 25% do not inject. Patients may be asked: 'Would you like me to examine your veins?' Regular drug users appreciate that this forms part of a full medical assessment, and vein care is very important to them.

The age and number of needle track marks can be determined. Blood staining may be noted on the skin or clothing. There will often be old, mature venous scars from previous drug using periods as well as recent venipunctures. Faint blue or pink linear scars indicate regular needle use from six to twelve months previously. White, depigmented scars usually indicate at least a year without venipunctures at that site. Apart from the medial and lateral cubital veins, the radial carpal, posterior forearm, cephalic, mid-basilic and superficial axillary veins may be favoured. Rarely, the superficial femoral vein is accessed with a long needle.

The use of such alternative veins may be due to 'collapse' of other venous access or as an attempt to conceal intravenous drug use from others, including family members. Stories of injecting into the orbits, web spaces, genitalia and other nether regions are exceedingly rare in clinical practice and may be based upon custodial anecdotes like the swallowing of razor blades.

Most heroin addicts inject two to four times daily. Since these venipunctures generally heal in about one week, such patients usually have 14 to 28 venipunctures of varying ages, often in the same site/s. Cocaine users often inject up to ten times in the one session and, unlike heroin users, tend not to re-inject at precisely the same site, but move along the vein each time. The one vein may reveal up to ten needle marks of the same age. This appearance is pathognomonic of cocaine use.

Needle marks from blood tests or transfusion service donations are more pronounced than self-injection as they employ much larger needles which are often in situ longer. They are also usually single rather than multiple.

Pin-point pupils in a patient with recent venipunctures is evidence of heroin use within the previous two hours. Although such patients may be alert in company, when left alone for a short time they will usually display the typical 'nodding off' syndrome with involuntary scratching and drowsiness. Such patients are usually unable to pass a urine specimen, possibly due to autonomic effects.

Opioid withdrawal invariably causes very large pupils. A patient with mid-point pupils is thus unlikely to be either intoxicated or in frank withdrawal from narcotics.

Bilateral red conjuctivae very often indicate cannabis use within the previous two hours. There may also be a glazed and staring look, with inappropriate affect. The patient who appears oblivious to stressful situations may also be using cannabis. Like some who abuse benzodiazepines, these patients are more likely to be unduly familiar and forgetful.

Patients who appear intoxicated, but do not have alcohol on the breath, are almost invariably under the influence of tranquillizers. They may be unsteady and drowsy with slurred speech and drooping eyelids. Such patients are often unduly familiar and they sometimes realign chairs in the interview situation.

Blood pressure and abdominal findings should also be recorded, and the patient weighed. All of these findings are fundamental to good medical management, just as checking optic fundi, auscultation and urinalysis in new blood pressure patients.

Psychiatric patients sometimes harbour delusions of illicit drug use and addiction. Some do use such drugs and become addicted, while others have never used illicit drugs. Those with physical habits may require methadone, and this should be arranged in consultation with the patient's psychiatrist.

Patients who are psychotic, severely depressed, or very young should have a second medical opinion for the protection of both the patient and physician. This may be obtained from the patient's own family doctor or a specialist in the appropriate field. It should be possible to obtain these opinions on the same day so that dosing is not delayed unduly.

While extremely rare in practice, it is important to guard against a non-addict applying for methadone treatment. If an absence of venipunctures or other atypical features lead to doubts about the patient's drug use, then dosing should be delayed until after positive confirmation.

BLOOD TESTING

Unless recently performed, blood tests should be recommended on initial presentation. HIV-1 and 2, hepatitis B and C antibodies and syphilis serology should be ordered in addition to a blood count, kidney and liver function tests, fasting sugar and lipids. Many physicians in this field advise repeat testing every six to twelve months for well patients who are still at risk.

For long term patients, or for those on high dose (>120mg daily) a trough methadone level may also be performed. The peak serum methadone level is reached three to six hours after dosing and is usually approximately double the twenty four hour trough level in stable patients. Methadone levels generally correlate well with clinical signs, and they can be very reassuring for the patient and doctor in those with rapid drug metabolism.

Serum methadone levels are usually expressed in milligrams per litre with a therapeutic range from 0.10 to 1.00mg/l (= 100 to 1000ng/ml). The molecular weight of methadone is 345.9 for molar (SI) conversions. Dole states that the level should be kept above 0.20mg/l to avoid cravings in susceptible patients.

HOW MUCH HEROIN ARE THEY USING?

HOW MUCH METHADONE TO GIVE?

It is both compassionate and practical to begin treatment as promptly as possible where patients present in withdrawals. In most cases this should be on the same day, as long as there is sufficient time to document the patient's dependency and to comply with the necessary legal formalities.

Patients may drop out of treatment in the first week due to inadequate dosing, but excessive doses combined with continued illicit drug use can also lead to serious problems (20). Hence the importance of giving sufficient methadone to alleviate withdrawals, but in a manner that avoids toxicity.

The patient's estimate of their own heroin and other non-opioid drug consumption should be recorded. The sums spent on illicit drugs give some indication of the quantity compared with others presenting for treatment. The number of injections is also an indicator of consumption, and this can be corroborated by inspection of venipuncture sites. One injection daily would indicate a lesser habit, with four or more per day indicating a more severe chemical dependency.

Initial dosing with methadone has some parallels with the use of other long acting drugs such as cardiac glycosides and phenytoin which also take several days to reach therapeutic levels with once daily dosing. The half-life of methadone has been reported to vary from twenty and eighty hours in different individuals. It is therefore not possible to know the patient's requirement until after approximately four days of equilibration on a given dose. A clinical review at this time may reveal some patients who require further dose increases and others who may need reductions.

The lethal dose of methadone in a non-tolerant adult is approximately 70mg. Therefore a safe starting dose for the majority of new patients is 30 to 40mg. A lower starting dose, such as 20mg, should be considered in those weighing less than 55kg, or in those whose history and examination indicates the use of smaller quantities of opioids. New patients who are intoxicated should have their first dose delayed or reduced.

Many prescribers recommend 40mg daily with 5mg increases each day for the first week. This is relatively safe, although it may not eliminate cravings in all patients.

Some physicians allow small supplementary doses or split doses in the early period for patients who are still in withdrawals, on condition that physical examination reveals no toxicity. Such doses should be separated by at least five hours. Adjustments may be in the range of 5mg to 15mg, making a possible maximum of 55mg for the first twenty four hours, in divided doses, under supervision. Where this is done, extra care must be taken in the following days as cumulative levels may become toxic. Further increases may be permitted in this way where withdrawals are experienced, but only in circumstances where the patient can be examined regularly.

Patients having excessive methadone dosage may oversleep and miss their dose for the following day. Non-attendance may therefore indicate excessive doses in some, but in others, the poor attendance may be due to inadequate doses and the continued use of street drugs. Hence the importance of careful history taking and examination in such cases.

Some new patients do not believe that the methadone is responsible for the disappearance of cravings, but that some other change has come over them. Apparently confirmed by successfully missing a day or two, these patients may stop attending for medication. This is often followed by a relapse to illicit drug use, when methadone treatment should again be made available if desired by the patient.

The average maintenance dose in most studies is approximately 65mg, with over 90% of patients doing well in the range from 25mg to 150mg. Patients are on the correct dose when they feel well and can sleep normally without cravings for additional drugs.

New patients should be warned not to drive or operate machinery until their methadone dose has been stable for at least ten days.

FINANCES - PRIVATE OR PUBLIC.

New patients often have outstanding legal, financial, domestic and housing problems to attend to. If they have no prospect of affording private health care, they should be accommodated in the public sector. The private practitioner should help to document any urgency and refer the patient to the appropriate public facility to ensure prompt attention. As with other simple forms of medical treatment one extra 'urgent' patient should always be accommodated, even if only on a temporary basis, until a permanent treatment position can be found. There should be no waiting lists for methadone treatment. Each day that a patient is denied appropriate treatment, the risk of legal, infective and toxic sequelae are compounded. Delays can also cause the 'window of opportunity' for satisfactory treatment to be lost altogether.

It is often said that if the patient spent $50 per day on illicit drugs, then $10 daily should be easy to find for treatment. This logical progression is spurious however, considering the one common goal of all treatment is to normalise patients' lives. It is untenable to place the patient in the position where an illicit source of income is needed to stay in treatment. On the other hand, it is a conundrum that attendance at a free clinic may save the patient $50 per week, which may then be spent on illicit drugs! Like tobacco and gambling expenses, these items are often given a budgetary priority which non-smokers and non-gamblers are unable to comprehend.

The private health sector has been largely responsible for the unprecedented expansion of treatment of the late 1980s in a political climate where few governments were able to fund new medical services. Private treatment services have also pioneered 'same day service', extended dosing hours, higher average doses, an end to waiting lists in some areas, extended take-home dosing in stable patients and concomitant on-site treatment of other medical problems. They have also bred a new advocate for the cause of ethical drug and alcohol treatment.

WHEN TO REVIEW IN EARLY TREATMENT?

In the first two weeks of treatment the significant risk of toxicity from a combination of methadone and street drugs must be taken into account. New patients should ideally be seen twice weekly during this period, and thereafter on a weekly basis until stability is achieved.