Managing a bipolar II state has three principal components: medication, the development of a stay-well plan and psychoeducation.
In terms of medication, most international treatment guidelines recommend a mood stabiliser, with lithium and lamotrigine the two most commonly nominated stabilisers. In the author’s view, lamotrigine is the drug of choice and has a distinctively superior cost-benefit ratio to lithium in managing those with a bipolar II disorder. Lithium has a number of significant side effects (including weight gain, tremor and a deceptively common significant cognitive impairment) and requires close monitoring to ensure that thyroid and renal function are not compromised.
However, there are several nuances to lamotrigine prescription. The key concern is that it might cause allergic responses such as Stevens-Johnson syndrome (SJS). To avert such a risk it is strongly recommended that lamotrigine be started at a dose of 25 mg every night for one week, and increased by 25 mg a week to a maximum of 200 mg as the target endpoint (this off-label dosage is based on the author’s practice for the past 10 years, and most psychiatrists work to a similar schedule). However, about 10% of patients will need only 100 mg, 10% will need up to 300 mg and 5% may need up to 400 mg. The risk of SJS is forewarned by a rash occurring on any part of the body; therefore, the patient should be instructed to cease lamotrigine immediately if such a rash occurs. The occurrence of a rash is uncommon (found in five to 10% of cases) and when it does occur, it generally appears in the first few weeks.
Lamotrigine can also cause toxic epidermal necrolysis (TEN) and drug reaction involving eosinophilia and systemic symptoms (DRESS) – severe reactions that, albeit very rare, may require hospitalisation. Another important consideration, based on the author’s personal observation, is that the branded version of the drug should be prescribed as many of the generic preparations appear to have either insufficient or too much lamotrigine. Many patients who, after years of successful management on branded lamotrigine, have been encouraged by pharmacists to take a generic formulation either assume that the medication must have ‘pooped out’ (become ineffective), or develop a late skin reaction – indicating insufficient and excessive real doses, respectively.
Apart from the risk of rash, side effects of branded lamotrigine are extremely rare, and the prescriber can expect about 70% of patients will report that the medication has stabilised their mood and they have no significant side effects (including no weight gain or sexual dysfunction) – a profile that is quite rare for psychotropic medications.
If lamotrigine fails, then lithium and sodium valproate are the next most commonly recommended mood stabilisers, although the latter should never be prescribed for women in their years of fertility in light of risking induction of polycystic ovarian syndrome. In a small percentage of patients, selective serotonin reuptake inhibitors and serotonin–norepinephrine reuptake inhibitors can achieve mood stabilisation as monotherapies (with several studies showing their utility), although they may become ineffective after months or several years.