sertraline

 

Sertraline
Systematic (IUPAC) name
(1S)-cis-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro- N-methyl-1-naphthalenamine
Identifiers
CAS number	79617-96-2
ATC code	N06AB06
PubChem	68617
DrugBank	APRD00175
Chemical data
Formula	C17H17Cl2N
Mol. mass	306.229 g/mol
Pharmacokinetic data
Bioavailability	44%
Metabolism	N-demethylation (liver)
Half life	~26 hours
Excretion	Renal
Therapeutic considerations
Pregnancy cat.	C
Legal status	℞ Prescription only
Routes	Oral

Sertraline hydrochloride (Zoloft, Lustral) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It was introduced to the market by Pfizer in 1991. Sertraline is primarily used to treat clinical depression in adult outpatients as well as obsessive-compulsive, panic and social anxiety disorders in both adults and children. Sertraline shares the common side effects and contraindications with other members of SSRI class; however, it does not cause weight gain. Controversy and legal actions have resulted from the suspicion that sertraline, similarly to other antidepressants, may increase the risk of suicide. In 2006 it was the most prescribed antidepressant on the U.S. retail market with 28,060,000 prescriptions.^[1]

History

The history of sertraline^[2][3] goes back to the beginning of 1970s when Pfizer chemist Reinhard Sarges synthesized a norepinephrine reuptake inhibitor tametraline^[4] Tametraline's development was soon stopped because of undesired stimulant effects observed in animals. Several years later, biochemist Kenneth Koe and chemist Willard Welch generated and tested derivatives of tametraline in vitro for the serotonin reuptake inhibition. Welch then prepared stereoisomers of the most promising candidate, which were tested in vivo by animal behavioral scientist Albert Weissman. The most active (+)-cis-isomer was taken into further development and eventually became sertraline. During the development, the group had to overcome the initial reluctance of Pfizer bureaucracy to pursue sertraline, as Pfizer was considering licensing an antidepressant candidate from another company.

Sertraline was approved by the Food and Drug Administration (FDA) in 1991 based on the recommendation of the Psychopharmacological Drugs Advisory Committee. The committee achieved a consensus that sertraline is safe and efficient for the treatment of depression. During the discussion, Paul Leber, Director of the FDA Division of the Neuropharmacological Drug Products noted that it was a "tough decision", since the treatment effect on outpatients with depression is "modest to minimal". Other experts emphasized that the drug's effect on inpatients is not different from placebo and criticized poor design of the trials by the drug's manufacturer Pfizer.^[5] For example, 40% of the participants dropped out of the trials, significantly decreasing their validity.^[6]

Until 2003, sertraline was only approved for use in adults ages 18 and over; that year it was approved by the FDA for use in treating children ages 6 to 17 with extreme obsessive compulsive disorder (OCD). In 2003 the UK Medicines and Healthcare Products Regulatory Agency issued a guidance that SSRIs, except fluoxetine (Prozac) are not suitable for the treatment of depression in minors,^[7][8]. However, sertraline still can be used for the treatment of OCD in children and adolescents.^[9] In 2005 the FDA, changed the labeling of antidepressants, including sertraline, adding a black box warning pertaining to pediatric suicidality, followed in 2007 by the warning regarding the suicidality in young adults.

The patent for Zoloft brand of sertraline expired in 2006,^[10] and the drug is now available in generic form.

Indications

Sertraline has been approved for the following indications: depression, obsessive-compulsive disorder (OCD),^[11] post-traumatic stress disorder (PTSD),^[12] premenstrual dysphoric disorder (PMDD),^[13] panic disorder (PD)^[14] and social phobia/social anxiety disorder.^[15]

Depression

The original clinical trials demonstrated only moderate efficacy of sertraline for depression (see History). Nevertheless, later research firmly established sertraline as one of the drugs of choice for the treatment of depression in outpatients.

Comparison with tricyclic antidepressants

Sertraline has a similar effect on the core depressive symptoms as the tricyclic antidepressants (TCAs); however, it is better tolerated and results in a better quality of life.

For example, similar improvement of depression scores was in comparative studies of sertraline versus clomipramine (Anafranil) ^[16] and amitriptyline (Elavil).^[17][18] At the same time, sertraline resulted in a much lower rate of side effects than amitriptyline (49% vs 72% vs 32% for placebo), particularly dry mouth, somnolence, constipation and increased appetite.^[18] However, there were more cases of nausea and sexual dysfunction in the sertraline group.^[17][18] Furthermore, sertraline patients showed a greater improvement of the subjective quality of life on such measures as work satisfaction, subjective feeling, perceptions of health and cognitive function.^[18]

A large and thorough double-blind study compared sertraline, prescribed for chronic (longer than 2 years) depression or depression with dysthymia, to the "gold standard" of depression treatment TCA imipramine (Tofranil). Sertraline was equivalent to imipramine for both of these indications during the first 12 weeks of the study^[19][20][21] and the 16 weeks continuation phase.^[22] Only 11% of patients on sertraline suffered severe side effects vs. 24% on imipramine. Constipation, dizziness, tremor, dry mouth, micturition disorder and sweating adverse effects were observed more often with imipramine, and diarrhea and insomnia with sertraline.^[20] Sertraline patients also reported significantly better social and physical functioning. Interestingly, the patients who achieved a remission during the trial (30% of the sample) did not differ from the healthy population on the measures of marital, parental, physical and work functioning and were close to normal on social adjustment and other measures of interpersonal functioning.^[21]

Comparison with other antidepressants

Comparative clinical trials demonstrated that sertraline's efficacy in depression is similar to moclobemide (Aurorix)^[23], nefazodone (Serzone),^[24], escitalopram (Lexapro)^[25], bupropion (Wellbutrin).^[26], citalopram (Celexa), fluvoxamine (Luvox), paroxetine (Paxil) and mirtazapine (Remeron).^[27] Remarkably, the patients on sertraline had much higher rate of sexual dysfunction (61% vs 10% for men and 41% vs 7% for women), nausea, diarrhea, somnolence and sweating as well as rate of discontinuation due to the side effects (13% vs 3%) than the patients on bupropion.^[26] Meta-analysis by the independent Cochrane Collaboration indicated that sertraline is more effective for the treatment of depression than fluoxetine (Prozac) (probability of response 1.4 times higher) and, possibly, is better tolerated.^[28] Three comparative studies of sertraline and venlafaxine (Effexor) has been conducted. In the first study supported by the venlafaxine manufacturer Wyeth^[29] and in the second — by the sertraline manufacturer Pfizer,^[30] sertraline performed marginally worse on some psychiatric scales and similarly to venlafaxine on others. However, the former study was criticized for the methodology shortcomings.^[31] A third study, funded by Pfizer, found no differences between sertraline and venlafaxine.^[32]

Depression in elderly

Sertraline used for the treatment of depression in elderly (older than 60) was superior to placebo and comparable to another SSRI fluoxetine, and TCAs amitriptyline, nortriptyline (Pamelor) and imipramine. Sertraline had much lower rate of adverse effects than these TCAs, for the exception of nausea, which occurred more frequently with sertraline. In addition, sertraline appeared to be more effective than fluoxetine or nortriptyline in the older than 70 subgroup.^[33] A more recent trial of sertraline vs placebo in elderly showed a statistically significant, that is unlikely to occur by chance, but clinically very modest improvement in depression and no improvement in quality of life.^[34] The authors were sharply criticized by Bernard Carroll, a one time chairman of the FDA Psychopharmacological Drugs Advisory Committee,^[35] for presenting these results as positive: "The study has all hallmarks of an experimercial, a cost-no-object exercise driven by a corporate sponsor to create a positive publicity for its product in a market niche... Thus does the corporate mandate to put lipstick on the pig prevail over the academic duty to communicate independent analysis of the data."^[36]

Other indications

Sertraline can also be used in the treatment of general anxiety disorder,^[37] binge eating disorder,^[38] and premature ejaculation.^[39]

There is also evidence that sertraline may be effective in the treatment of refractory neurocardiogenic syncope in children and adolescents.^[40]

A study has shown that sertraline is an effective treatment for impulsive aggressive behavior in personality disordered patients.^[41]

It has also been used to treat Tourettes Syndrome.

Adverse effects

According to the manufacturer of Zoloft brand of sertraline Pfizer, sertraline is contraindicated in individuals taking monoamine oxidase inhibitors or pimozide (Orap). The alcohol-containing sertraline concentrate is contraindicated with disulfiram (Antabuse).^[42] The prescribing information recommends that the treatment of the elderly and patients with liver impairment "must be approached with caution". Due to the slower elimination of sertraline in these groups, their exposure to sertraline may be as high as three times the average exposure for the same dose.^[42]

Among the common adverse effects associated with sertraline and listed in the prescribing information, the effects with the greatest difference from placebo are nausea (25% vs 11% for placebo), ejaculation failure (14% vs 1% for placebo), insomnia (21% vs 11% for placebo), diarrhea (20% vs 10% for placebo), dry mouth (14% vs 8% for placebo), somnolence (13% vs 7% for placebo), dizziness (12% vs 7% for placebo), tremor (8% vs 2% for placebo) and decreased libido (6% vs 1% for placebo).^[42] Those that most often resulted in interruption of the treatment were nausea (3%), diarrhea (2%) and insomnia (2%).^[42]

Akathisia, that is "inner tension, restlessness, and the inability to stay still", caused by sertraline was observed in 16% of patients in a case series.^[43] This and other reports^[44][45][46] note that akathisia begins soon after the initiation of treatment or increase of the dose, often, several hours after taking the medication. Akathisia usually disappears within several days after sertraline is stopped or its dose is decreased. In some cases, clinicians confused akathisia with anxiety, and increased the dose of sertraline causing further worsening of the patients' symptoms. The experts note that because of the possible link of akathisia with suicide and the distress it causes to the patient, "it is of vital importance to increase awareness amongst staff and patients of the symptoms this relatively common condition".^[47][48]

Over more than six months of sertraline therapy for depression, patients showed an insignificant weight increase of 0.1%.^[49] Similarly, a 30 months-long treatment with sertraline for OCD, resulted in a mean weight gain of 1.5% (1 kg).^[50] Although the difference did not reach statistical significance, the weight gain was lower for fluoxetine (Prozac) (1%) but higher for citalopram (Celexa), fluvoxamine (Luvox) and paroxetine (Paxil) (2.5%). Only 4.5% of the sertraline group gained a large amount of weight (defined as more than 7% gain). This result compares favorably with placebo, where, according to the literature, 3–6% of patients gained more than 7% of their initial weight. The large weight gain was observed only among female members of the sertraline group; the significance of this finding is unclear because of the small size of the group.^[50]

Birth defects and effects on breast-fed infants

The studies comparing the levels of sertraline and its principal metabolite, desmethylsertraline, in mother's blood to their concentration in umbilical cord blood at delivery indicated that the fetus's exposure to sertraline and its metabolite is approximately a third of the maternal exposure.^[51][52] The use of sertraline during the first trimester of pregnancy was associated with the increased odds of the following birth defects: omphalocele—six-fold, septal defects—two-fold, anal atresia and limb reduction defects—four-fold.^[53] Concentration of sertraline and desmethylsertraline in the breast milk is highly variable and, on average, is of the same order of magnitude as their concentration in the blood plasma of the mother. As a result, more than half of the breast-fed babies receive less than 2 mg/day of sertraline and desmethylsertraline combined, and in most cases these substances are undetectable in their blood.^[54] No changes in the serotonin uptake by the platelets of breast-fed infants were found, as measured by their blood serotonin levels before and after their mothers began sertraline treatment.^[55]

Sexual side effects

The observed frequency of the sexual side effects depends greatly on whether they are reported by patients spontaneously, as in the manufacturer's trials, or actively solicited by the physicians. There have been several double-blind studies of the sexual side effects comparing sertraline with placebo or other antidepressants.^[56] While nefazodone (Serzone) and bupropion did not have negative effect on sexual functioning, 67% of men on sertraline experienced ejaculation difficulties vs. 18% before the treatment^[56] (or 61% vs 0% according to another paper^[26]). Similarly, in a group of women who initially had not have difficulties achieving orgasm, 41% acquired this problem during treatment with sertraline.^[26] The 40% rate of orgasm dysfunction (vs 9% for placebo) on sertraline was observed in a mixed group in another study.^[57] Sexual arousal disorder defined as "inadequate lubrication and swelling for women and erectile difficulties for men" occurred in 12% of sertraline patients as compared with 1% of patients on placebo. At the same time, sexual desire and overall satisfaction with sex stayed the same, as in the beginning of the sertraline treatment, and slightly below the placebo.^[57]

Suicidality

The FDA requires all antidepressants, including sertraline, to carry a black box warning stating that antidepressants may increase the risk of suicide in persons younger than 25. This warning is based on statistical analyses conducted by two independent groups of the FDA experts that found a 2-fold increase of the suicidal ideation and behavior in children and adolescents, and 1.5-fold increase of suicidality in the 18–24 age group.^[58][59][60]

Suicidality in adults

Suicidal ideation and behavior in clinical trials are rare. For the above analysis, the FDA combined the results of 295 trials of 11 antidepressants for psychiatric indications in order to obtain statistically significant results. Considered separately, sertraline use in adults decreased the odds of suicidality with a marginal statistical significance by 37%^[60] or 50%^[59] depending of the statistical technique used. The authors of the FDA analysis note that "given the large number of comparisons made in this review, chance is a very plausible explanation for this difference".^[59] The more complete data submitted later by the sertraline manufacturer Pfizer indicated increased suicidality.^[61] Similarly, the analysis conducted by the UK MHRA found a 50% increase of odds of suicide-related events, not reaching statistical significance, in the patients on sertraline as compared to the ones on placebo. ^[62][63]

Discontinuation syndrome

Main article: SSRI discontinuation syndrome

Abrupt interruption of sertraline may result in withdrawal or discontinuation syndrome. This syndrome occurred in 60% of the sertraline subjects in a blind discontinuation study, as compared to 14% of fluoxetine and 66% of paroxetine subjects.^[64] During the 5-8 days of the sertraline discontinuation, the most frequent symptoms reported by more than a quarter of patients were irritability, agitation, dizziness, headache, nervousness, crying, emotional lability, bad dreaming and anger. Approximately one third of the subjects experienced mood worsening to the level generally associated with a major depressive episode.^[64]

Mechanism of action

Sertraline is primarily a serotonin reuptake inhibitor. Therapeutic doses of sertraline (50-200 mg/day) taken by patients for four weeks resulted in 80-90% inhibition of serotonin transporter (SERT) in striatum as measured by positron emission tomography. 9 mg/day was sufficient to inhibit 50% of SERT.^[65] It is also a dopamine reuptake inhibitor, but this effect is 100 times weaker compared to its serotonin reuptake inhibition.^[66] Sertraline weakly blocks α1-adrenoreceptors with 1-10% of its serotonin reuptake inhibition potency.^[66][67] As mainly an SSRI, sertraline blocks the reuptake of serotonin and in effect, keep the neurotransmitters longer on the synapse. This allows more time for the receptors to recognize the serotonin and send the nerve impulse.

Pharmacokinetics

Taken orally, sertraline is absorbed slowly, achieving its maximal concentration in the plasma 4-6 hours after ingestion. 98.5% of sertraline in the blood is bound to the plasma proteins. Its half-life in the body is 13-45 hours and is about 1.5 times longer in women (32 hours) than in men (22 hours), resulting in the proportionally 1.5 higher exposure of women.^[68] According to in vitro studies, sertraline is metabolized by several cytochrome 450 isoforms: CYP2D6, CYP2C9, CYP2B6, CYP2C19 and CYP3A4, and it appeared unlikely that inhibition of any single isoform could cause clinically significant changes of the sertraline pharmacokinetics.^[69][70] No differences in sertraline pharmacokinetics were observed between people with high and low activity of CYP2D6;^[71] however, poor CYP2C19 metabolizers had a 1.5 higher level of sertraline than the normal metabolizers.^[72] In vitro data also indicate that the inhibition of CYP2B6 should have even greater effect than the inhibition of CYP2C19, while the contribution CYP2C9 and CYP3A4 to the sertraline metabolism would be minor. These conclusions, though, have not been verified in human studies.^[70] Sertraline can be deaminated in vitro by monoamine oxidases; however, this metabolic pathway has never been studied in vivo.^[70] The major metabolite of sertraline, desmethylsertraline, is about 50-time weaker serotonin transporter inhibitor than sertraline and its clinical effect is negligible.^[67]

Interactions

Sertraline is a moderate inhibitor of CYP2D6 and CYP2B6 in vitro.^[73] Accordingly, in human trials it caused an increased blood level of such CYP2D6 substrates as metoprolol (Lopressor, Toprol XL), desipramine (Norpramin), imipramine (Tofranil) and nortriptyline (Pamelor) and CYP3A4/CYP2D6 substrate haloperidol (Haldol). This effect was dose-dependent; for example, desipramine co-administration with 50 mg of sertraline resulted in a 20% increase of exposure and with 150 mg of sertraline—in a 70% increase of exposure.^[68][74] In a placebo-controlled study, the concomitant administration of sertraline caused a 40% increase of the blood level of methadone, which is primarily metabolized by CYP2B6.^[75] Sertraline had a slight inhibitory effect on the metabolism of diazepam (Valium), tolbutamide (Orinase) and warfarin (Coumadin), which are CYP2C9 or CYP2C19 substrates; this effect was not considered to be clinically relevant.^[68] As expected from the in vitro data, sertraline did not alter the human metabolism of CYP3A4 substrates erythromycin, alprazolam (Xanax), carbamazepine (Tegretol), clonazepam (Klonopin), and terfenadine (Seldane) as well as CYP1A2 substrate clozapine (Clozaril). Sertraline had no effect on the actions of digoxin (Lanoxin) and atenolol (Tenormin), which are not metabolized in the liver.^{[68][73][42][76]} Case reports suggest that taking sertraline with phenytoin (Dilantin) or zolpidem (Ambien) may induce sertraline metabolism and decrease its efficacy and taking sertraline with lamotrigine (Lamictal) may increase the blood level of lamotrigine via an unknown mechanism. Clinical reports indicate that interaction between sertraline and MAOIs isocarboxazid (Marplan) and tranylcypromine (Parnate) may cause serotonin syndrome. In a placebo-controlled study of co-administration of sertraline with lithium, 35% of the subjects experienced tremors versus 0% with placebo.^[68]

Controversy

The brand-name form of sertraline, Zoloft, was widely advertised to consumers as "correcting a chemical imbalance", a claim not found in the FDA-approved product labeling. Hundreds of millions of dollars were spent promoting Zoloft this way while it was still on-patent. Some have argued that this advertising may lead consumers to believe that they must take Zoloft to recover when in fact they may benefit from other non-medical treatments such as psychotherapy or exercise.^[77]

In the case of Hawkins v The Commonwealth (an Australian court case from the state of New South Wales), Zoloft was described as an important factor in David Hawkins' murder (through strangling) of his wife. Hawkins had been depressed, was prescribed 50 mg of Zoloft a day and on his first day of treatment took 250 mg. He claimed on the night of the murder that he couldn't sleep, was agitated and claimed he had hallucinations during the attack on his wife. As a result of this case Zoloft received a large amount of negative publicity, with questions being raised about its impact on behaviour.^[78]

In 2004, a Los Angeles nurse sued Pfizer as a private attorney general "on behalf of all California residents who have been misled about Zoloft", claiming the company covered up side effects.^[79]

A well-publicized essay published in the December 2005 issue of open access journal PLoS Medicine claimed the direct-to-consumer advertising for Zoloft has been very misleading and could well violate FDA regulations.^[77]

References