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Drugs & Toxicology

Therapeutic drug monitoring, antibiotics, anticonvulsants, toxicology, and medication-related lab conversions.

About Drugs & Toxicology Conversions

Drug levels are converted constantly in therapeutic drug monitoring (TDM), where a dose is adjusted to keep a medicine inside a safe, effective window. This category covers the anticonvulsants (phenytoin, carbamazepine, valproic acid), the cardiac drug digoxin, local anaesthetic and stimulant levels (lidocaine, caffeine), and key toxicology tests — acetaminophen/paracetamol and blood alcohol.

What makes these tools different from a plain converter is the therapeutic and toxic context attached to each. Phenytoin has to be read against albumin because most of it is protein-bound; carbamazepine induces its own metabolism so levels drift; acetaminophen overdose is judged against the timed Rumack-Matthew nomogram, not a fixed number; and blood alcohol is expressed three ways — mg/dL, mmol/L and BAC percentage. Each dedicated page pairs the conversion with those ranges and caveats.

Available Calculators

Browse all drugs & toxicology tools available on ConvertMedUnits.com.

Valproic Acid Unit Converter Convert valproic acid levels between µmol/L and µg/mL using molecular weight. Phenytoin Unit Converter Convert phenytoin between µg/mL and µmol/L with the 3.96 factor, plus total/free ranges and albumin correction. Carbamazepine Unit Converter Convert carbamazepine between µg/mL and µmol/L with the 4.23 factor and the 4–12 µg/mL therapeutic range. Acetaminophen (Paracetamol) Unit Converter Convert acetaminophen / paracetamol between µg/mL and µmol/L with the 6.62 factor and the overdose nomogram line. Ethanol (Blood Alcohol) Unit Converter Convert ethanol between mg/dL, mmol/L and BAC percentage with the 0.2171 factor and legal-limit reference levels. Digoxin Unit Converter Convert digoxin therapeutic drug monitoring results between ng/mL and nmol/L. Caffeine Unit Converter Convert caffeine serum or plasma levels between µg/mL and µmol/L for monitoring and toxicology review. Lidocaine Unit Converter Convert lidocaine serum or plasma levels between µg/mL and µmol/L for therapeutic monitoring and toxicity review.

Frequently Asked Questions

Common questions about drugs & toxicology lab unit conversions.

What is therapeutic drug monitoring?

It is measuring the blood level of a medicine to keep it within a target range — high enough to work, low enough to avoid toxicity. Drugs with a narrow window, like phenytoin, carbamazepine and digoxin, are monitored this way.

Why do drug levels need unit conversion?

US labs usually report in µg/mL or ng/mL while many other countries use µmol/L or nmol/L. Because therapeutic and toxic thresholds are unit-specific, converting correctly is essential to avoid misreading a level.

Is a lab alcohol level the same as legal BAC?

Not exactly. Laboratory serum or plasma ethanol runs about 10–15% higher than the whole-blood alcohol used in legal testing, so a lab value should not be treated as a legal blood alcohol concentration.