**Core Concept**
Hepatic porphyrias are a group of disorders caused by defects in the production of heme, a vital molecule for various bodily functions. In these conditions, certain medications can precipitate acute attacks by inducing the production of toxic porphyrin intermediates.

**Why the Correct Answer is Right**
In hepatic porphyrias, certain medications can worsen symptoms by inducing the production of toxic porphyrin intermediates. Safe anticonvulsants do not induce the cytochrome P450 enzymes, which are responsible for producing these toxic intermediates. Among the safe options, carbamazepine is particularly useful for managing seizures in patients with hepatic porphyrias.

**Why Each Wrong Option is Incorrect**
**Option A:** Phenytoin is a known inducer of cytochrome P450 enzymes, making it a poor choice for patients with hepatic porphyrias. It can exacerbate the condition by increasing the production of toxic porphyrin intermediates.
**Option B:** Phenobarbital is another enzyme inducer that can worsen symptoms in patients with hepatic porphyrias. Like phenytoin, it can increase the production of toxic porphyrin intermediates, precipitating an acute attack.
**Option C:** Primidone is a barbiturate that can also induce cytochrome P450 enzymes, making it a poor choice for patients with hepatic porphyrias.

**Clinical Pearl / High-Yield Fact**
When managing seizures in patients with hepatic porphyrias, it's essential to choose anticonvulsants that do not induce cytochrome P450 enzymes. This can help prevent exacerbating the condition and reduce the risk of acute attacks.

**Correct Answer: C. Carbamazepine.**