Benzodiazepines

Benzodiazepines are a class of sedative/transquilliser drugs used in medical practice to treat anxiety, or induce sleep.  The class act on the ‘benzodiazepine receptor’ which regulates the rate of secretion of the inhibitory neurotransmitter GABA (gamma amino butyric acid) in the brain.

The class includes many well-known products, notably diazepam (Valium), temazepam, lorazepam (Ativan), and nitrazepam (mogadon).

Effects and abuse potential

All benzodiazepines have the potential to produce physical or psychological dependence when used in high doses or for a prolonged period of time, with doses of 100mg per day of diazepam or 300mg of chlordiazepoxide liable to cause physical dependence[ii].  While  it was common for these drugs to be prescribed on a long-term basis between the 1960s and 1980s, the abuse potential has restricted recommended prescribing regimes to a maximum of 2-4 weeks.  Short-acting benzodiazepines carry the greatest abuse potential.

Many long-term dependent users of Benzodiazepines were middle-aged or elderly women who acquired their dependency as a result of medical treatment before such dangers were fully-realised. Among ‘traditional’ groups of drug users, benzodiazepines are rarely the drug of first choice, but may be used in a secondary capacity by opiate users when opiates are unavailable, or by stimulant users seeking to ‘come down’.  There is a limited market for such drugs, as only a small proportion of those who had tried them reported non-prescription prices.

Side effects of benzodiazepines include Drowsiness and lightheadedness, confusion and ataxia, amnesia may occur, dependence, paradoxical increase in aggression, occasionally headache, vertigo, hypotension, salivation changes, gastrointestinal disturbances, rashes, visual disturbances changes in libido, amnesia, respiratory depression, urinary retention, blood disorders and jaundice; on intravenous injection: pain, thrombophlebitis and rarely apnoea.  Driving: drowsiness may affect performance of skilled tasks (e.g. driving).  Interactions: effect of alcohol enhanced Alcohol, Neuroleptics, Antidepressants - enhanced sedation.

Research on Benzodiazepine Consumption

There is little recent research as to the amounts of benzodiazepines consumed by heavy non-medical drug users.  Robson[iii] reported that a large majority of attenders at drug dependency units use benzodiazpines from time to time, “often in huge doses”, and that “the equivalent of 20-30 times the manufacturers recommended dose is not unusual” due to the development of tolerance.

IDMU Drug User Surveys: Data from IDMU survey respondents between 1999 and 2010 (total n=23637) found 11% of respondents reported having used ‘tranx’ or tranquillisers (Table 2), with 1.9% using regularly or daily (17.5% of those who had ever used).  As with other drugs, user ratings were significantly associated with the frequency of use, with regular users giving the highest ratings (higher than daily where dependency may be considered a downside) and never-used the lowest, daily users consumed an average of 95x tabs per week (13.5 tabs/day).

Less than one percent of the overall sample (6% of ‘ever users) reported buying the drug monthly or more frequently, spending on average a modest £10 (median) to a maximum of £1200 per month on these drugs.  The majority of ‘never used’ and ‘blank’ respondents reported zero values for purchase and spending but both categories included a handful of individuals purchasing relatively large quantities of tablets (presumably dealers).  One quarter of tranx users obtained these drugs on prescription, 20% of whom supplemented their prescriptions with illicit tablets.  Excluding zero values (including spending by those prescribed the drugs), the consumption and spending levels at different percentiles were as follows (table 3).

Only a handful of respondents who had tried tranquillisers have reported a regular pattern of use or spending on these drugs, the usage of the vast majority falling within prescribing guidelines, with a small minority of excessive users taking up to 14-40 pills a day.

As the paper surveys did not distinguish between different types of tranquilliser due to lack of space, the IDMU Web-surveys (2004-2010) allowed more detailed questions to be asked of respondents. Diazepam has been by far the most common tranquilliser reported by drug users, followed by Temazepam, Alprazolam, Lorazepam & Nitrazepam.  Average weekly use of, spending on and user ratings of the drugs mentioned by at least 2 or more respondents are shown in table 4.  Average consumption of Diazepam was just over 4x tabs per day, Alprazolam 6-7x tabs per day and Temazepam 11x tabs per day.

Summary

Regular use of benzodiazepines has been discontinued in medical practice due to the risk of dependency.  Regular users of illicitly obtained benzodiazepines can develop tolerance to the effects so as to exceed the recommended maximum dose by a substantial margin.  Our survey data supports the evidence of Robson that daily tranquillizer users may take 20-30 times the recommended therapeutic dose of benzodiazepines.

[i] British National Formulary/MIMS/Wikipedia

[ii] Hoffman FG (1983) A handbook of drug and alcohol abuse.  Oxford University Press p125

[iii] Robson PE (1994) Forbidden Drugs.  Oxford Medical Publications p119-121