Bipolar disorder is characterized by episodes of mania, hypomania, and depression. Recurrences of manic or (more frequently) depressive symptoms are common. About 15-20% of patients with bipolar disorder die by suicide.

The FDA has approved cannabidiol oral solution (Epidiolex – Greenwich Biosciences) for treatment of seizures associated with Dravet syndrome or Lennox-Gastaut syndrome in patients ≥2 years old. Cannabidiol (CBD) is a cannabinoid constituent of the marijuana plant (Cannabis sativa). It is the first natural marijuana product to be approved by the FDA for any indication and the first drug to be approved in the US for treatment of Dravet syndrome. Stiripentol (Diacomit), which is not a marijuana product, was also recently approved by the FDA for treatment of Dravet syndrome in combination with clobazam (Onfi) and will be reviewed in a future issue.

The FDA has warned that the antiepileptic and mood-stabilizing drug lamotrigine (Lamictal, and generics) can rarely cause hemophagocytic lymphohistiocytosis (HLH), a serious and potentially fatal immune-related reaction.1

HLH, which can be familial, occurs most often in infants, but can occur at any age. Often induced by Epstein-Barr Virus infection (HIV infection and non-Hodgkin's lymphoma are other common triggers), HLH is characterized by an unremitting activation of CD8+ T cells and macrophages.2 If untreated, it causes organ damage, particularly in the liver, bone marrow, and CNS; organ failure and death occur within months after onset.3 Clinical features can include fever and rash, splenomegaly, hepatitis, cytopenias, elevated triglyceride levels or low fibrinogen levels, hyperferritinemia, hemophagocytosis, decreased or absent natural killer cell activity, and elevated blood CD25 levels.4

The optimal treatment for drug-induced HLH is unclear. Treatment of HLH generally involves use of corticosteroids and blood products, sometimes augmented by aggressive immunosuppression with the cytotoxic drug etoposide (Toposar, and generics). The anti-CD52 antibody alemtuzumab (Lemtrada) can be added in refractory HLH cases,5 and allogeneic hematopoietic cell transplantation has been used in genetic cases.

Since lamotrigine first became available in 1994, five confirmed and three suspected cases of HLH associated with its use have been reported. All of these cases occurred within 24 days of starting treatment and required hospitalization. One death was reported; in the other cases, improvement occurred after discontinuation of lamotrigine and treatment of HLH. Because initial signs and symptoms of HLH are nonspecific, the condition can be confused with Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), another potentially fatal, multiorgan, immune-related adverse reaction associated with lamotrigine use.1,6

Patients being treated successfully with lamotrigine should continue taking it. Clinicians should monitor patients taking lamotrigine for signs and symptoms of HLH, especially during the first few weeks after starting the drug.

1. FDA Drug Safety Communication: FDA warns of serious immune system reaction with seizure and mental health medicine lamotrigine (Lamictal). Available at: www.fda.gov. Accessed June 7, 2018.
2. M Ramos-Casals et al. Adult haemophagocytic syndrome. Lancet 2014; 383:1503.
3. SA Parikh et al. Prognostic factors and outcomes of adults with hemophagocytic lymphohistiocytosis. Mayo Clin Proc 2014; 89:484.
4. JI Henter et al. HLH-2004: Diagnostic and therapeutic guidelines for hemophagocytic lymphohistiocytosis. Pediatr Blood Cancer 2007; 48:124.
5. RA Marsh et al. Salvage therapy of refractory hemophagocytic lymphohistiocytosis with alemtuzumab. Pediatr Blood Cancer 2013; 60:101.
6. SH Kardaun et al. Drug reaction with eosinophilia and systemic symptoms (DRESS): an original multisystem adverse drug reaction. Results from the prospective RegiSCAR study. Br J Dermatol 2013; 169:1071.

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Treatment of epilepsy should begin with a single antiepileptic drug (AED), increasing its dosage gradually until seizures are controlled or adverse effects become intolerable. If seizures persist, specialists generally recommend trying at least one and sometimes a second alternative drug as monotherapy before considering use of two drugs concurrently. When used for the appropriate seizure type, AEDs are roughly equivalent in efficacy. Drug choice is usually based on factors such as ease of use, adverse effects, drug interactions, presence of comorbidities, and cost.

View the Comparison Table: Some Oral Antiepileptic Drugs

Bipolar disorder is characterized by intermittent episodes of mania and/or depression. Even with maintenance treatment, recurrences of manic or (more frequently) depressive episodes are common. Some of the drugs and dosages recommended here have not been approved by the FDA for use in bipolar disorder.

Drugs are not the only treatment for psychiatric illness. Psychotherapy remains an important component in the management of these disorders, and cognitive behavioral therapy (CBT) can be used for many of them as well. Electroconvulsive therapy (ECT) has a long history of efficacy and safety when drugs are ineffective or cannot be used.

Treatment of epilepsy should begin with a single drug, increasing the dosage gradually until seizures are controlled or adverse effects become unacceptable. If seizures persist, expert clinicians generally prescribe at least one and sometimes a second alternative drug as monotherapy before considering use of two drugs at the same time. When used for the appropriate seizure type, antiepileptic drugs are roughly equivalent in efficacy. The choice of drug is usually based on factors such as ease of use, adverse effects, interactions with other drugs, presence of comorbid conditions and cost.

The FDA has approved ezogabine (ee-ZOE-ga-been; Potiga – GSK/Valeant) for oral adjunctive treatment of partial-onset seizures in adults. Ezogabine is available in Europe as retigabine (Trobalt).

Clobazam (Onfi – Lundbeck), an oral benzodiazepine, has been approved by the FDA for adjunctive treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients ≥2 years old. It has been available in Canada (Frisium) and other countries for years for treatment of anxiety and many types of epilepsy.

Drugs are not the only treatment for mood disorders. Psychotherapy remains an important component in the management of these disorders, and electroconvulsive therapy (ECT) has a long history of efficacy and safety when drugs are ineffective, poorly tolerated or cannot be used. Some drugs are recommended here for indications that have not been approved by the FDA.

Pain can be acute or chronic. Chronic pain has been broadly classified into two types: nociceptive and neuropathic. Nociceptive pain can be treated with nonopioid analgesics or opioids. Neuropathic pain is less responsive to opioids; adjuvant medicines such as antidepressants and anticonvulsants are often used to treat neuropathic pain. Combining different types of analgesics may provide an additive analgesic effect without increasing adverse effects.

The FDA has approved vigabatrin (vye gá ba trin; Sabril – Lundbeck) for oral use as add-on therapy for complex partial seizures in adults who are refractory to several antiepileptic drugs and as monotherapy for infantile spasms. Vigabatrin has been available in other countries for many years. Because of its potential for retinal toxicity, it will be available in the US only through a restricted distribution program called SHARE (Support, Help and Resources for Epilepsy). Prescribers and pharmacists distributing the drug must register, and patients must undergo visual field testing.

The equivalence of generic drugs to their brand-name precursors continues to be controversial. The last Medical Letter review of this subject (2002) concluded that well-documented therapeutic inequivalence between brand-name and FDA-approved generic drugs had not been reported. Is that still true? New data have become available for some drugs.

The FDA has approved lacosamide (Vimpat - UCB Pharma) for oral or intravenous (IV) use as add-on therapy in adults with partial-onset seizures.

Rufinamide (Banzel - Eisai), a triazole derivative structurally unrelated to other marketed antiepileptic drugs (AEDs), has been approved by the FDA for treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients ≥4 years old.

Treatment of epilepsy should begin with a single drug, increasing the dosage gradually until seizures are controlled or adverse effects become unacceptable. If seizures continue and further dosage increases appear inadvisable because of adverse effects, most Medical Letter consultants generally prescribe at least one and sometimes a second alternative drug as monotherapy before considering use of two drugs at the same time. Most antiepileptic drugs initially approved by the FDA only as adjunctive therapy for partial seizures may also be effective for other types of seizures and as monotherapy. Studies suggest that when used for the appropriate seizure type, antiepileptic drugs are roughly equivalent in efficacy. The choice of a drug is usually based on factors such as ease of use, adverse effects and cost.

Drugs are not the only treatment for psychiatric illness. Psychotherapy remains an important component in the management of these disorders, and cognitive behavioral therapy (CBT) is used for many of them as well. Electroconvulsive therapy (ECT) has a long history of efficacy and safety when drugs are ineffective or cannot be used.

Treatment of epilepsy should begin with a single drug, increasing the dosage gradually until seizures are controlled or adverse effects become unacceptable. If seizures continue and further dosage increases appear inadvisable because of adverse effects, most Medical Letter consultants generally prescribe at least one and sometimes a second alternative drug as monotherapy before considering use of two drugs at the same time. Most antiepileptic drugs initially approved by the FDA only as adjunctive therapy for partial seizures may also be effective for other types of seizures and as monotherapy.

Pregabalin (Lyrica - Pfizer), a structural analog of gamma-aminobutyric acid (GABA) similar to gabapentin (Neurontin - Pfizer, and others), which recently became available generically, has been approved by the FDA for treatment of neuropathic pain associated with postherpetic neuralgia (PHN) and diabetic peripheral neuropathy (DPN), and for adjunctive treatment of partial onset seizures in adults with epilepsy.

An extended-release formulation of carbamazepine, available since 1997 for treatment of epilepsy, has now been approved under a new name, Equetro, for acute mania and mixed episodes of bipolar disorder. Although the drug was effective in some patients for up to 6 months, it has not been approved for maintenance treatment. Carbamazepine has not been shown to be more effective than lithium or valproate, and it can cause serious adverse effects.

Three types of analgesic drugs are available: non-opioids, including aspirin, other nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen; opioids; and adjuvant drugs that are not usually thought of as analgesics, such as antidepressants, which can act as adjuvants when given with NSAIDs or opioids, or have analgesic activity of their own in some types of pain. Combining two different types of analgesics may provide an additive analgesic effect without necessarily increasing adverse effects.

The fixed-dose combination of olanzapine and fluoxetine (Symbyax - Lilly) has been approved by the FDA for treatment of depressive episodes associated with bipolar disorder. Olanzapine alone (Zyprexa), which is mainly used as an antipsychotic (Medical Letter 2003; 45:102), is FDA-approved for treatment of acute manic episodes and for maintenance treatment of bipolar disorder. Fluoxetine alone (Prozac, and others), which is mainly used as an antidepressant (Medical Letter 2003; 45:93), has no specific approval for use in bipolar disorder.

The number of drugs marketed for psychiatric indications has increased sharply in recent years. The recommendations in this article are based on the results of controlled trials and on the experience and opinions of Medical Letter consultants. Interactions with other drugs can be found in The Medical Letter Handbook of Adverse Drug Interactions, 2003.

Treatment of epilepsy should begin with a single drug, increasing the dosage gradually until seizures are controlled or adverse effects become unacceptable. If seizures continue and further dosage increases appear inadvisable because of adverse effects, most Medical Letter consultants generally prescribe at least one and sometimes a second alternative drug as monotherapy before considering use of two drugs at the same time. Most antiepileptic drugs initially approved by the FDA only for adjunctive therapy are probably also effective as monotherapy. Many of the drugs used to treat epilepsy interact with each other (see table beginning on page 63) and with other drugs; for interactions with other drugs, see The Medical Letter Handbook of Adverse Drug Interactions, 2003. The treatment of status epilepticus is not included here.

Anticonvulsants are now widely used for treatment of psychiatric illnesses, particularly bipolar disorder. Lithium is the standard drug for treatment of bipolar disorder, but it can cause severe toxicity, serum concentrations must be monitored, and it is not effective in some patients.

Zonisamide (Zonegran - Elan Pharma), a sulfonamide chemically unrelated to other antiepileptic drugs, has been approved by the FDA for adjunctive use in adults with partial seizures. Zonisamide has been available in Japan for more than 10 years.

Oxcarbazepine, which is chemically similar to carbamazepine, and levetiracetam, a pyrrolidine acetamide chemically unrelated to other antiepileptic drugs, are the sixth and seventh drugs approved by the US Food and Drug Administration in the last five years for oral use in partial seizures.

Topiramate (Topamax - Ortho-McNeil) has been approved by the US Food and Drug Administration (FDA) for oral use as an adjunct to other drugs in adult patients with partial seizures. Since this diagnostic category includes the largest number of patients with refractory epilepsy, new drugs with antiepileptic activity are usually tried first for this indication. Topiramate (toe pyre' a mate) is a structurally unique agent chemically related to the D-enantiomer of fructose.

Lamotrigine (la mo tri jeen; Lamictal - Burroughs Wellcome), a phenyltriazine derivative, has been approved by the US Food and Drug Administration for use in addition to other antiepileptic drugs in adults with partial seizures. Since this diagnostic category includes the largest number of patients with intractable epilepsy, new drugs with antiepileptic activity are usually tried first for this indication. Lamotrigine was first marketed abroad in 1990 and is now available in more than 50 other countries.