D&A Fact Sheet 02 – Effects of Alcohol and Other Drugs

Extent of Drug Use

Workplace policies need to have a strategy for addressing the impairment caused by the use of drugs and alcohol. A survey conducted by the Victorian Occupational Health and Safety Commission found cannabis use was reported by 7% of workers at work (refer to information sheet 7).

In 1991, 32% of the adult population had tried marijuana, 8% amphetamines, 7% hallucinogens, 5% barbiturates, 2% heroin, 2% ecstasy and 3% inhalants.

Alcohol and Other Drugs, Chemicals and Performance

Both legal and illegal drugs can be broadly categorised as depressants, stimulants or hallucinogens. Most drugs, including medication, even in very low doses, could affect the capacity of an employee to carry out their duties safely.

Workplaces use chemicals on a daily basis and particular chemicals can cause impairment to employees, and can have a similar effect to types of drugs. Where chemicals are used a strict hierarchy of hazard control should be implemented and workers should be educated in the potential hazards.



Alcohol is the most commonly used depressant drug. Alcohol in combination with other factors, affects mental and motor function, the level of impairment being related to the blood alcohol level.

Blood Alcohol Concentrate (BAC) which is determined by how much a person drinks and over what period of time’ is affected by a number of factors

  • Gender – females will almost always have a higher BAC.
  • Body size – A smaller person will have a higher BAC.
  • Weight – people with low body weight can be more affected.
  • Health/Fitness.
  • An empty stomach.
  • Aging effects – your body’s response to drugs and alcohol in a number of ways.

After an alcohol drink, the alcohol is absorbed rapidly into the bloodstream. The time it takes between the last drink and the point at which blood alcohol concentration (BAC) peaks can range from 30-90 minutes. On average you can metabolise 6-8 grams of alcohol every hour. Therefore, a bit less than one standard drink per hour is cleared from the body.

The effects of alcohol on performance can be:

  • Loss of inhibition;
  • Impairment of coordination, judgement,Intellectual capacity, and slowing of reflexes;
  • Blurred vision;
  • Slurred speech;
  • Hangover – headache, shakiness nausea and vomiting;
  • Reduced awareness of environment;
  • Limited response to things going on around you; and
  • Feeling sleepy.

Long term affects (may) include: Damage to the liver, heart and stomach

  • Damage to the brain – impairment of memory, difficulty learning new skills.

Drugs that may have a warning not to drive or operate heavy machinery include, but are not limited to:

  • Antihistamines (for allergies);
  • Benzodiazepines (for sleepy and anxiety);
  • Monoamine oxadise inhibitors (for depression); and
  • Phenthiazines (for mental disorders).

Minor Tranquillisers

These are drugs usually prescribed by a doctor for treatment of anxiety and sleeplessness. They may cause drowsiness and impair motor coordination, judgement reaction time and intellectual capacity. The effects are greatly increased when mixed with alcohol. These drugs come under the name of benzodiazepines and include Valium, Serapax, Mogadon and Normison. Daily use over time can lead to dependence, and withdrawal symptoms may include increased anxiety, agitation, disturbed sleep, pain and flu like symptoms.

Other prescription medications that can affect performance in the workplace are barbiturates and other sedative hypnotics, which include Amytal, Nembutal, Seconal, and Sodium Pentothal.

Opiate analgesics

These drugs are used to relieve pain, they may also produce a euphoric effect, and impair the ability to drive and operate machinery. They can cause nausea and vomiting, constipation, and depress breathing. Long-term effects include tolerance, dependence and withdrawal symptoms. Intravenous use of these substances may pose a serious danger from life threatening infections e.g. Hepatitis, HIV and other blood borne diseases.

  • Opium
  • Morphine
  • Codeine (can be available as a component of cold medications or medications for pain relief – e.g. Panadeine Forte and Panamax Co)
  • Heroin
  • Pethidine
  • Methadone

Opiates are readily available – either by obtaining prescriptions for medications that contain opiates or by purchasing them illicitly on the black market.

Note: Methadone – people prescribed regular doses of methadone for dependence on heroin, do not generally suffer impairment, which would effect their work performance.


Antihistamines are prescribed or purchased over the counter as allergy or cold remedies. Some of these antihistamines can cause drowsiness and impaired performance and should not be mixed with alcohol.


Known as pot, dope, marijuana and hashish. Can also be classified as a depressant with hallucinogenic properties. In the short-term cannabis use can impair motor coordination, short-term memory, tracking ability, sensory functions and perception. Long-term use it may cause lasting memory impairment, decreased sperm count and motility in males, interfere with ovulation in females and impair immune responses.

Other Drugs

Non-opiate analgesics

This drug group includes aspirin, paracetamol and some anti-inflammatories used for arthritis. In recommended doses this group have no effects that could affect a person’s capacity to work safely. However, the effect of pain on an employee’s ability to carry his/her duties in a “safe” manner needs to be discussed with their GP.


Stimulants are drugs that stimulate the Central Nervous System and can elevate a person’s mood and wakefulness. Negative symptoms produced by stimulants include anxiety, restlessness, confusion, impatient and aggressive behaviour, poor judgement, tremors, increased blood pressure and heart rate, which can potentially result in a heart attack or stroke. Withdrawal from this type of drug can result in fatigue, restlessness and depression. In some people use of stimulants can result in paranoia, hallucinations and irrational behaviour.

Types of stimulants include

  • Amphetamines (illegal, or on prescription in forms such as dexamphetamine). Also known colloquially as “speed”. Pseudoephedrine – which is an ingredient in cough mixtures, is often used as a base ingredient in the manufacturing of illegal amphetamines.
  • Cocaine
  • MDMA, also know as ecstasy
  • Caffeine

Note: All of these drugs produce dependency


Hallucinogens are capable of producing profound alteration of perception and thought processes.

LSD (illegal)

Known as acid. LSD can produce profound alterations to perception and sensory functions. It can also produce brain damage.


Inhalants are liquid or aerosol products such as petrol, solvents (e.g. Hexane, Toluene) or glues. These drugs can be used by individuals to achieve a “high” or can be inhaled inadvertently at work. If these substances are used in a workplace, the risks have to be addressed.

The effects include

  • drowsiness,
  • disorientation,
  • anxiety and tension,
  • nausea and vomiting,
  • sensitivity to sunlight,
  • eye irritation and
  • double vision.

Inhalants can cause death from arrhythmia (irregular heart beat) or suffocation.

Long-term exposure can cause significant health risks. Refer to hazard sheets on the UnionSafe website.

Pesticides e.g. Organophosphate, Organochlorine

These chemicals can produce effects similar to tranquillisers.

Effects include

  • drowsiness,
  • slowed reaction time, headache,
  • giddiness,
  • confusion,
  • ataxia,
  • slurred speech and
  • convulsions.
  • Can also produce `flu’ like symptoms and impairment of vision.

When mixed with alcohol the effects are increased. In high doses these chemicals have a stimulant effect, producing poor coordination and excitability. Over exposure can cause violent convulsions, coma and death.

The OHS Regulation 2001 provides information and employers under the hazard clause of the OHS Regulation are required to address the risks associated with exposure to chemicals and hazardous substances. Refer to Easy Guide to the Law – Hazardous Substances – Employers’ Responsibilities.

Download more info:
D&A Fact Sheet 02 – Effects of Alcohol and Other Drugs including Health Effects

Sign up for updates