Uzmi ovu dozu lijeka sada, a drugu prije spavanja.

Uzmi is the imperative form, used to give a command: take.

More specifically:

• infinitive: uzeti = to take
• imperative (singular, informal): uzmi = take!

This is the form you would use when speaking to:

• one person
• informally

If you were speaking formally or to more than one person, you would say:

• Uzmite ovu dozu lijeka sada, a drugu prije spavanja.

Because ovu dozu is the direct object of the verb uzmi.

Croatian changes noun and adjective forms depending on case. After a verb like take, the thing being taken goes in the accusative case.

So:

• nominative: ova doza = this dose
• accusative: ovu dozu = this dose (as the object of take)

Both words change because ovu must agree with dozu in:

• gender: feminine
• number: singular
• case: accusative

For the same reason as ovu dozu: it is also in the accusative singular feminine.

The full phrase would be:

• drugu dozu = the other/second dose

But Croatian often leaves out a noun when it is obvious from context. So after ovu dozu, the sentence simply says drugu, and dozu is understood.

So this part literally works like:

• take this dose now, and the other one before sleep

Because doza often takes a noun in the genitive to show what the dose is a dose of.

So:

• doza lijeka = a dose of medicine

This is very common in Croatian with words expressing quantity or measure, such as:

• čaša vode = a glass of water
• komad kruha = a piece of bread
• doza lijeka = a dose of medicine

So:

• doza = the unit/amount
• lijeka = what that amount consists of

Here a means something like:

• and
• while
• whereas
• and then / and the other one

In this sentence, a connects two instructions:

• Uzmi ovu dozu lijeka sada
• a drugu prije spavanja

It does not sound strongly contrastive here; it simply links the two parts in a natural way. English would most naturally translate it as and in this context.

Because the preposition prije means before, and it requires the genitive case.

So:

• prije
  • genitive

The word spavanje means sleeping / sleep / going to bed as a verbal noun. Its genitive singular form is:

• spavanja

So:

• prije spavanja = before sleeping / before bed / before going to sleep

This is a very common structure in Croatian:

• prije jela = before eating / before the meal
• prije puta = before the trip
• prije spavanja = before sleep / before bedtime

It is related to a verb.

It comes from:

• spavati = to sleep

From that verb, Croatian forms the verbal noun:

• spavanje = sleeping

Then after prije, it becomes genitive:

• spavanja

So although it behaves like a noun in the sentence, it is built from a verb. English does something similar with forms like before sleeping.

Yes, absolutely.

Both are possible:

• Uzmi ovu dozu lijeka sada, a drugu prije spavanja.
• Uzmi ovu dozu lijeka sada, a drugu dozu prije spavanja.

The version with just drugu sounds natural because dozu is already obvious from the first part of the sentence.

Croatian often omits repeated nouns when the meaning is clear.

In this context, it most naturally means the other or the second dose.

So the idea is:

• one dose now
• the second/other dose before bed

By itself, drugi/druga/drugo can mean:

• other
• another
• second

The exact meaning depends on context. In a medical instruction like this, English usually understands it as the second dose.

Yes, Croatian word order is fairly flexible.

The sentence:

• Uzmi ovu dozu lijeka sada, a drugu prije spavanja.

could also be rearranged in natural ways, for example:

• Sada uzmi ovu dozu lijeka, a drugu prije spavanja.
• Uzmi sada ovu dozu lijeka, a drugu prije spavanja.

All of these are understandable. The original version sounds very natural and clear.

In Croatian, word order often changes for:

• emphasis
• rhythm
• style

Here, placing sada after ovu dozu lijeka keeps the instruction balanced:

• this dose now
• the other before bed

This is about aspect, which is very important in Croatian.

These two verbs are a pair:

• uzeti = perfective
• uzimati = imperfective

Very roughly:

• uzeti focuses on a completed single action: take
• uzimati focuses on process, repetition, or habitual action: be taking / take repeatedly

In a one-time instruction like this, Croatian normally uses the perfective imperative:

• Uzmi = Take (it now / do this once)

If you are told to take a dose at a specific moment, the perfective verb is the natural choice.

You would change uzmi to uzmite.

So the formal version is:

• Uzmite ovu dozu lijeka sada, a drugu prije spavanja.

This is used:

• when addressing one person formally
• or more than one person

Everything else in the sentence can stay the same.