Two beers, an allergy tablet and a 14-month-old licence
Nikos is 23 and has held his category B licence for 14 months. At a taverna he drank two 330 ml beers (about 4% alcohol) between 21:00 and 22:00 and ate a full meal. At 22:15, during a hay-fever attack, he took one diphenhydramine tablet, as he does most springs. At 23:30 his friends tell him he is "fine to drive"; the taverna is 6 km from home on quiet town streets. He feels slightly drowsy and his eyes are itchy. On the way home he is stopped at a police checkpoint and asked to take a preliminary breath test. He has no previous offences, the car is insured and has a valid ΚΤΕΟ certificate. He argues that two beers cannot matter, that he ate, and that the tablet is "just an allergy pill from the pharmacy, not a drug".
1. Which alcohol limit applies to Nikos, and is he likely to be above it at 23:30? Show the arithmetic and the uncertainty in it.
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The limit is not the general one. Greek law sets 0.50 g/L for experienced drivers but 0.20 g/L for drivers licensed for less than two years (and for professional drivers). Nikos is 14 months in, so he is held to 0.20 g/L - the same threshold as a professional taxi driver.
The arithmetic. Two 330 ml beers at 4% contain roughly 2 × 13 g = 26 g of pure alcohol. For a 75 kg man, peak blood alcohol is roughly 0.35–0.45 g/L; elimination is about 0.10–0.15 g/L per hour. By 23:30 (1.5–2.5 h after drinking) he may be anywhere from about 0.15 to 0.30 g/L.
The uncertainty is the point. Body mass, food, liver metabolism and the exact strength of the beer can move that estimate by ±0.1 g/L. He is straddling his legal limit, and
2. Setting the legal limit aside, what is the correct decision at 23:00, and why does the tablet matter?
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Do not drive; take a taxi or walk. The decision rests on three stacked risks:
- Sedation. Diphenhydramine is a first-generation antihistamine that crosses into the brain and causes drowsiness, slowed reactions and blurred near vision. Its effect lasts 4–6 hours, so at 23:30 it is still near peak. Modern non-sedating alternatives (loratadine, cetirizine) are not identical either - cetirizine can still impair some drivers.
- Synergy. Alcohol and sedating antihistamines act on the same depressant pathways. The combination is worse than the sum: one beer plus one tablet can produce impairment equivalent to several beers alone. "I only had two beers" is not a defence when the medicine is in the blood.
- Fatigue. It is late; he has already had a long day. Fatigue alone raises crash risk comparable to moderate alcohol.
Greek law covers driving under the influence of medicines as well as alcohol, so being under 0.20 g/L does not make him fit to drive if his fitness is impaired. Feeling "fine" is not evidence - impaired drivers systematically misjudge their own performance. The 6 km distance is irrelevant: most crashes happen close to home.
3. At the checkpoint, what should he do - and what if he refuses the breath test?
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Comply calmly and completely. He should identify himself, produce licence, registration and insurance, and blow properly into the device. Refusing, or blowing deliberately badly, is treated in Greek practice as an offence in its own right - the sanctions are those of driving under influence, and it removes any chance of showing he was under the limit.
If the preliminary test is positive, he is entitled to a confirmatory test (breath analysis or blood). The result is what matters, not his opinion or his friends'. Expect licence suspension, an administrative fine, penalty points and, above the higher threshold, criminal proceedings.
The medicine will come out anyway - the officer will ask about medicines, and honesty is better than a later discovery. It will not exculpate him; it may aggravate the picture of impairment.
The practical lesson. With a 0.20 g/L limit, a novice driver has effectively no drinking margin. The only reliable plan is: no alcohol at all if driving, and read the pictogram on every medicine leaflet before getting behind the wheel.