The word "drug" can have connotations of illicitness , whereas medication is always used in licit contexts.
But a drug can refer to licit medicines as well.
New drugs come on the market.
A drug is typically ingested (or injected) whereas medications can also be topical.
Not that we don't say "topical drug" too, but "topical medication" is used more often and has been in use since the 1840s, whereas "topical drug" is a fairly recent usage, arising in the 1950s per Google ngram .
So, they're more or less interchangeable, except in illicit contexts, where drug is used.
The criminal is said to be a "drug dealer", or a "drug runner", and the addict is said to be "hooked on drugs" or "on drugs".
The patient is said to be "on medication".
ell.stackexchange.com/users/10264/Tᴚoɯɐuo
Medications are substances that are taken with the intention of healing or improving health.
Drugs can refer to any substance that has an effect on the body — positive, negative, intentional, or side-effect.
For example: Cannabis is a drug.
If you are using it to treat pain or cancer, it's a medication.
If you're just smoking it for fun, you're just using it as a drug.
Alcohol is a drug.
You might be able to call it a medication if you are taking it on a doctor's advice, but it would be a bit of a stretch.
Athletes who take performance-enhancing drugs may refer to them as "medications", but I would consider that usage a euphemism.
Whether the word drug has a positive or negative connotation depends on the context.
A "drug store" would generally be a legitimate business; a "drug deal" usually implies illegal activity.
Drug delivery is an active area of scientific research, but sometimes "drug delivery" is used in the other sense .
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Medicine is a type of drug.
All medicines are drugs, not all drugs are medicines.
In AE (not sure about BE), "drug" tends to have an illicit connotation, so it is better to use "medicine" for clarity if there is a chance of misunderstanding.
ell.stackexchange.com/users/409/Kevin
I think a drug is just a raw state of a chemical and a medicine is the use of a particular chemical to prepare something to change the body's state in positive way.
For instance, the use of acetaminophen.
If it is taken "raw" or as it is a chemical regardless of the quantity and without any additives or other ingredients, that can be termed as a drug because taken in that alone can have both positive and negative effects on your body.
In a case where other additives are added to acetaminophen, it becomes a medication because it has been prepared to treat a disease.
ell.stackexchange.com/users/48801/chrispa.
All medicine is drugs but all drugs are not medicine.
Because Drug is the active ingredient used to modify physiological system or pathological states for the benefit of the recipient but it may not have a suitable form & dose.
On the other hand, Medicines are finished products, which contain drugs in active ingredient as well as the excipients and It has a suitable form & dose.
ell.stackexchange.com/users/52323/Md. Habibur Rahman
Drug is a chemical substance use to treat disease, illness and disorder that has dose and dosage.
While Medicine is a chemical substance use to treat disease, illness and disorder that does not have dose and dosage.
Example herbal medicine.
ell.stackexchange.com/users/113373/kadala Adamu
What's the difference between drug and medication?  Do you agree with Dose of medications=Dose of drugs?
What's the difference between drug and medication?
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<word-meaning><word-difference>
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ell.stackexchange.com/users/11935/Khashayar
Medicines are finished products that are taken with the intention of healing or improving health, which contain drugs as active ingredients. Medicines also have a suitable form and dose. A drug is the active ingredient used to modify physiological system or pathological states for the benefit of the recipient, but it may not have a suitable form and dose. Unlike medication, the word "drug"  can  have connotations of  illicitness. Drugs are any substances that have an effect on the body, whether positive or negative, licit or illicit. Medicines are finished products for health improvement.
Medicines are finished products for health improvement. Drugs are any substances that have an effect on the body, whether positive or negative, licit or illicit.