Because of the potential for cross-reactivity with other aromatic anticonvulsants, patients with anticonvulsant HSR should avoid phenytoin, phenobarbital and carbamazepine. As well, because primidone is metabolized to phenobarbital, it also likely has a high rate of cross-reactivity. Oxcarbazepine (not available in Canada) may be an alternative to carba-mazepine ; however, because results are conflicting , oxcarbazepine should be considered potentially crossreactive with carbamazepine. First-degree relatives should be warned of the potential for a reaction with an aromatic anticonvulsant. Benzodiazepines, valproic acid (not in the acute phase, because of the risk of hepatitis) or one of the newer anticonvulsants can be used for seizure control. If you need your treatment to start soon and are not too crazy about spending too much money, it’s time for you to discover the canadian neighbor pharmacy. This is a very affordable and safe pharmacy selling drugs of best quality and delivering them internationally in no time.

Other multisystemic adverse effects

Drug-induced lupus has been associated with ethosuximide , valproic acid , carbamazepine , phenytoin and primidone . In some patients, only antinuclear antibodies are present, whereas other patients describe classic lupus-like illness.


Most anticonvulsants are associated with asymptomatic increases in liver enzymes . In general, anticonvulsants should be discontinued when hepatic enzyme levels are greater than three times the normal level . However, routine screening is not warranted in most patients because routine blood and urine screening are unlikely to detect a presymptomatic phase; rather, attention to toxic symptoms or symptoms suggestive of a serious ADR is recommended . One study showed that a threefold increase in serum gamma-glutamyl transpeptidase (GGT) activity occurs in 90% of patients on long term phenytoin therapy , most likely as the result of enzyme induction. The rise in GGT is accentuated by regular consumption of alcohol. In a prospective study of 199 asymptomatic children who were receiving anticonvulsant drugs, 6% had transient minor abnormalities of blood studies necessitating rechecks. All were normal on repeat . As well, routine laboratory monitoring revealed hepatic enzyme elevations in 5% to 15%, and transient leucopenia in 12% of patients treated with carbamazepine, but did not predict life-threatening effects associated with its use.