Response to: ‘Quetiapine use: Science or clever marketing?’

To the Editor

Erik Monasterio and Andrew McKean (2013) warn ‘Part of the rapid diffusion of atypical antipsychotic (AAP) medications has been achieved by large increases in the rate of use in certain sub-populations, most notably youths for whom long-term data on safety and efficacy are still lacking …’.

They refer to their 2010 survey (Montaserio and McKean, 2011) which found 58% of psychiatrists prescribed quetiapine off-label every week. ‘Of those psychiatrists that had prescribed AAPs for an off-label indication, the most common first-line agent was quetiapine (94%).’

The USA study of 46,089 users of AAPs (Ray et al., 2009) found that the adjusted incidence-rate ratio for sudden cardiac death, according to use or non-use of AAPs (where persons with a baseline diagnosis of schizophrenia or related psychosis were excluded) for quetiapine was 1.49, p-value 0.06 (1.99 for olanzapine, 2.49 for risperidone; p < 0.001 for both). For a low dose (< 100 mg chlorpromazine equivalent) of any AAP, the ratio was 1.52 (p-value 0.08).

Monasterio and McKean (2011) highlighted that cases of quetiapine abuse have been increasingly reported and in the USA it has been referred to as Quell, Susie-Q, Baby Heroin, and Q-Ball.

Heilbronn et al. (2012) explain quetiapine-related overdoses are more likely to result in hypotension, respiratory depression, coma, or death compared with other antipsychotics.

Many other potential adverse effects of quetiapine exist, including interactions with erythromycin and grapefruit, and factors described on the Australian AstraZeneca datasheet but not mentioned on the www.medsafe.govt.nz website: (i) ‘Increased blood pressure has not been identified in the adult population but was seen in children and adolescents’ (The NZ Medsafe website datasheets refer to ‘changes in blood pressure’); (ii) ‘Concomitant use of ADHD medication and quetiapine is not recommended. If concomitant therapy is considered necessary, patients should be carefully monitored for the effect of the combination of treatments on the signs and symptoms of both ADHD and acute mania. Effects on blood pressure may be cumulative and blood pressure should be carefully monitored.’

However, ‘An advisory panel to the US Food and Drug Administration voted in favour of approving more limited use of quetiapine as an adjunctive therapy in treatment-refractory depression’ (Kuehn, 2009).

What I find is that in everyday inpatient and outpatient child and adolescent psychiatry, in spite of one’s best efforts to treat the underlying condition(s) and to introduce non-medical strategies, often in the short term and occasionally in the long term, one needs to prescribe an anxiolytic or hypnotic. I avoid prescribing zopiclone or benzodiazepines because of the potential for tachyphylaxis, dependence, disinhibition, and abuse; and because of hazards when driving or when combined with alcohol. Melatonin can be effective for early insomnia, but costs the patient $NZ 0.66 or more per day.

Thus, off-label prescribing of quetiapine for excessive anxiety or for insomnia is often the best alternative, as long as one monitors for side effects. Where such off-label prescribing of quetiapine is not centrally funded, the cost falls unfairly on the local health authority, or on the patient or caregiver. (In New Zealand the consumer does not pay more for an off-label prescription, than for a prescription for a registered indication.)