From the Guidelines

Antibiotics do not increase the seizure threshold, and certain beta-lactam antibiotics may actually lower it.

The pro-convulsive activity of beta-lactams varies, with some having a higher risk of inducing seizures than others, as shown in Table 1 from the study by 1.
Certain beta-lactams, such as Cefazolin and Cefepime, have a higher relative pro-convulsive activity compared to Penicillin G, with values of 294 and 160, respectively 1.
The risk of neurotoxicity, including seizures, is increased when plasma free concentrations of beta-lactam antibiotics exceed eight times the MIC 1.
Renal failure is a significant risk factor for neurological toxicity of beta-lactam antibiotics, as it can cause rapid accumulation of these drugs 1.
Specific beta-lactams, such as Cefepime and Ceftazidime, have a lower neurotoxicity threshold than others, and their use requires careful monitoring of plasma concentrations to minimize the risk of seizures and other neurological disorders 1.

From the Research

The relationship between antibiotics and seizure threshold is complex, with some studies suggesting that certain antibiotics may lower the seizure threshold, while others find no significant association 2, 3, 4, 5, 6.
Some antibiotics, such as penicillins, cephalosporins, fluoroquinolones, and carbapenems, have been reported to have a proconvulsive effect, particularly in patients with predisposing factors such as renal dysfunction, brain lesions, or a history of epilepsy 2, 3, 5.
The evidence for an association between antibiotic drugs and symptomatic seizures is generally low to very low, with most studies relying on case reports and case series 2, 3.
Certain antibiotics, such as imipenem, have been associated with seizures in critically ill patients, but careful use and dosing can minimize this risk 6.
The interaction between antibiotics and antiepileptic drugs can also affect the seizure threshold, with some combinations increasing the risk of seizures or drug-associated neurotoxicity 3, 5.

Patients with renal dysfunction, brain lesions, or a history of epilepsy may be at increased risk of seizures when taking certain antibiotics 2, 3, 5.
High doses or prolonged use of antibiotics can also increase the risk of seizures 2, 3, 5.
Certain underlying conditions, such as cerebral trauma, encephalitis, or meningitis, can also increase the risk of seizures in patients taking antibiotics 3, 5.

Clinicians should be aware of the potential for antibiotics to lower the seizure threshold, particularly in patients with predisposing factors 2, 3, 4, 5, 6.
Careful selection and dosing of antibiotics, as well as monitoring of serum levels and patient response, can help minimize the risk of seizures 2, 3, 6.
Patients with a history of epilepsy or seizures should be closely monitored when taking antibiotics, and alternative treatments should be considered if possible 3, 5.