Heterocyclic antidepressants in nonpsychiatric disorders

Heterocyclic antidepressants have been used successfully in the treatment of migraine, enuresis and encopresis, peptic ulcer disease, irritable bowel syndrome, chronic pain, narcolepsy, sleep apnea and attention deficit disorder. The mechanism of their therapeutic effects in these conditions is still unclear. Serotonergic, noradrenergic, anticholinergic and antihistaminic properties and rapid-eye-movement sleep suppression have been implicated.

A polygraphic study of one case of primary alveolar hypoventilation (Ondine's curse)

We report here on a case of primary alveolar hypoventilation in a 9 yr old child. From the age of 8 years, the patient has suffered from episodes of bronchopneumonia associated with severe respiratory insufficiency and lethargy. After recovery, cyanosis developed during the night and, later on, during the day. On two occasions, serious respiratory depression followed ketamine sedation for cardiac catheterization and total anaesthesia for cerebral angiography. Pulmonary function tests showed normal volumes and normal mechanics of breathing; blood gas analysis revealed a slight hypercapnic acidosis and hypoxia. The ventilatory response to CO2 was virtually absent, whereas voluntary hyperventilation normalized blood gas values. A polygraphic recording during sleep showed a marked worsening of hypoventilation, which occurred soon after falling asleep and continued throughout all sleep stages; sporadic central apnoeas, at times prolonged, were recorded only during light sleep. The patient, now 14 yr old, is maintained in satisfactory condition with low flow nocturnal oxygen administration combined with the use of a body respirator during sleep twice a week.

Theophylline improves pneumogram abnormalities in infants at risk for sudden infant death syndrome

To determine the efficacy of theophylline treatment in infants at increased risk for SIDS, we obtained 24-hour cardiorespiratory recordings (pneumograms) in 80 infants given theophylline in whom the initial pneumogram was abnormal. Fifty-three infants had a clinical diagnosis of near-SIDS, and 27 were asymptomatic siblings with a positive family history for SIDS. The initial pneumogram was obtained at a mean age of 6.9 weeks, and the repeat pneumogram 2.3 weeks later, when the mean theophylline blood concentration was 11.2 +/- 0.5 micrograms/ml. Theophylline treatment resulted in comparable and highly significant improvements in both groups. Among all 80 infants, apnea density decreased from 1.6 +/- 0.2% (SEM) to 0.3 +/- 0.1% (P less than 0.001), periodic breathing episodes/100 minutes decreased from 2.7 +/- 0.4 to 0.3 +/- 0.1 (P less than 0.001), and the longest apneic period decreased from 13.5 +/- 0.7 to 10.1 +/- 0.5 seconds (P less than 0.001). Findings on the pneumogram became completely normal with theophylline therapy in 87% of infants with near-SIDS and 81.5% of asymptomatic siblings. Pneumogram normalization was associated with absence of further symptomatic sleep apnea in the near-SIDS group and with continued absence of any clinical symptoms in the asymptomatic family history group. There were no deaths from SIDS.

Breathing during sleep: the responses to asphyxia and prochlorperazine in normal subjects and patients with obstructive sleep apnea

The effects of sleep and prochlorperazine (12.5 mg intravenous bolus) on the ventilatory and arousal responses to asphyxia were studied in normal subjects and patients with obstructive sleep apnea (OSA). The ventilatory response to asphyxia was reduced during non-rapid eye movement sleep in the six normal subjects studied (1.93 +/- 0.18 l min-1.% SaO2 awake vs. 1.01 +/- 0.10 l min-1.% SaO2 asleep; mean +/- SEM; p less than 0.01) (SaO2 = arterial oxygen saturation). In the two normal subjects studied during sleep following prochlorperazine administration, ventilatory responsiveness was increased (p less than 0.05) but arousal response to asphyxia was depressed (p less than 0.025). Although prochlorperazine increased waking ventilatory responsiveness to asphyxia in five of six patients with OSA (2.26 +/- 0.44 l min-1.% SaO2 vs. 4.77 +/- 1.39 l min-1.% SaO2; mean +/- SEM; p less than 0.01), the drug had no clinically significant effect on upper airway obstruction during sleep; in three patients, apnea frequency was slightly reduced but in four of six patients severity of hypoxemia during apnea was increased with drug administration. We conclude that prochlorperazine administration is unlikely to benefit patients with obstructive sleep apnea despite its ventilatory effects during wakefulness and sleep. This lack of effect may be explained by separate effects of the drug on ventilatory and arousal responses to asphyxia.

Naloxone, theophylline, bromocriptine, and obstructive sleep apnea. Negative results

A total of 28 male patients objectively diagnosed with obstructive sleep apnea syndrome (OSAS) participated in specific drug trials involving naloxone (an opioid antagonist), theophylline and bromocriptine mesylate (a dopamine agonist). All subjects were between 15 and 40% overweight. The group median apnea-hypopnea (A + H) index was 58. None of the drugs had any significant beneficial effects on the number and duration of upper airway apneas and hypopneas or directly related oxygen desaturation. Theophylline increased the diaphragmatic activity during REM sleep-related mixed apnea but had no impact on upper airway apnea in the studied population.

L-tryptophan in the treatment of impaired respiration in sleep

15 subjects (mean age: 48.2 yr; 13 males, 2 females) with sleep apnea (12 obstructive, 3 central) were treated with an average dose of 2500 mg L-tryptophan (L-T) at bedtime. Comparison of pre- and post-drug polysomnograms showed significant improvement in obstructive sleep apnea but not with central sleep apnea. Most dramatic improvement is seen in subjects with obstructive sleep apnea in non-REM sleep only, but severity of apnea appears to be the most important factor determining improvement. L-T increased REM time and shortened REM latency but had no other significant effects on sleep architecture. Serotoninergic activity with a defect in feedback control of tryptophan-serotonin metabolism is postulated as a potential mechanism in the pathophysiology of obstructive sleep apnea. The enhanced usefulness of L-T in combination with protriptyline is predicted based on early preliminary work at the OSU Sleep Center. The Potential influence of dietary intake on respiratory automaticity is reviewed.

The role of protriptyline in obstructive sleep apnea

Protriptyline, a non-sedating tricyclic agent, was evaluated in a double blind drug-placebo crossover trial in five obese patients with obstructive sleep apnea. Four of the five patients had improvement in somnolence. Protriptyline improved oxygenation. This seemed related primarily to a reduction (from 23% to 11%) in REM, with fewer of the more severe REM apneas. Arousal frequency remained quite high; thus the reason for the reduction in somnolence remains unclear. In three patients, at six months the improvement in clinical status and oxygenation persisted. We have now attempted long term treatment in nine patients. In five, anticholinergic side-effects necessitated stopping therapy. Four patients continue to do well. A trial of protriptyline is thus indicated in treatment of mild to moderate obstructive apnea or when the patient refuses more invasive treatment.

Sleep apnea

Sleep apnea is characterized by recurrent upper airway obstruction, resulting in periodic apneic episodes that are associated with oxygen desaturation and frequent awakenings. This leads to daytime somnolence and, possibly, pulmonary hypertension and cor pulmonale. Tracheostomy has been the standard treatment for severe sleep apnea with life-threatening complications. Several recent studies have reported benefits of protriptyline in obstructive sleep apnea. The drug does not completely resolve the apnea, but does improve nocturnal oxygenation and reduce daytime hypersomnolence. Protriptyline should be considered an alternative to tracheostomy in patients with benign or moderately severe obstructive sleep apnea.

Tricyclic antidepressants in the treatment of insomnia

The use of tricyclic antidepressants as opposed to hypnotics in treating insomnia is reviewed. Available data indicate that TCAs alleviate sleep disturbances related to depression (often before antidepressant effects are seen) and, in selected cases, may prove effective in disturbed sleep related to sleep apnea, fibrositis, and sleep related bruxism, as well as in adults with childhood onset insomnia or a history of hyperkinesis. However, TCAs share many of the problems reported for hypnotics, as well as having some potentially serious side effects not present with benzodiazepines. The need for determination of the etiology of sleep disorders, and specific pharmacotherapy directed toward identified causes rather than the symptom of insomnia, is stressed.

Why we need a tax on sleeping pills

In the United States every year the total costs of giving sleeping pills can be estimated at $500 million to $1 billion. Many if not most of the prescriptions are inappropriate. Sleeping pill use, associated with a 50% increase in overall mortality, is especially dangerous for older people, who have a high risk of sleep apnea. There is virtually no evidence that sleeping pills are effective with prolonged usage and no evidence for life-preserving benefits. Excessive use of sleeping pills should be discouraged with a tax of 4 per pill. Revenues from the tax should fund new research to determine which sleeping pills are safest and when alternative treatments are safer.

Ondine's curse: therapeutic trial of dimefline

Ondine's curse is a rare disorder characterized by primary failure of central regulation of breathing, resulting in severe hypoventilation during sleep. This report describes a 14-year-old girl with both this disorder and hypergonadotropic hypogonadism. As a therapeutic trial, dimefline was administered orally, which was effective in deepening respiration for certain periods of sleep, during which time blood gas levels improved significantly.

The effects of protriptyline in sleep-disordered breathing

The effects of therapy with the tricyclic antidepressant protriptyline were studied in 12 patients with hypersomnolence and moderately severe sleep apnea. After treatment there was no significant change in the duration or frequency of sleep-disordered breathing (SDB) during non-REM sleep, but there was an alteration in the breathing pattern characterized by a decrease in the amount of apnea during SDB events. Apnea, as a percent of disordered breathing time, fell from 60.4 +/- 27.2% to 35.5 +/- 26.7% (p less than 0.01) and was accompanied by a reduction in the peak fall in oxygen saturation from 16.2 +/- 6.2% to 9.2 +/- 4.7% (p less than 0.01). During REM sleep there was no change in the pattern, duration, or frequency of SDB, or reduction in the peak fall in oxygen saturation. However, there was a reduction in the amount of Stage REM sleep, thereby reducing the more severe SDB events (p less than 0.01) and further improving nocturnal oxygenation. In 10 of 12 patients, there was subjective improvement in daytime hypersomnolence, which was associated with an increase in median sleep onset time from 3.3 +/- 2.2 to 5.1 +/- 2.1 min (p less than 0.01). Although all patients developed mild side effects from the anticholinergic properties of protriptyline manifested by a dry mouth, 4 patients noted additional side effects including urinary hesitancy, mild constipation, and difficulty in maintaining an erection. One patient developed intolerable constipation that necessitated discontinuation of the drug. We conclude that protriptyline reduced daytime hypersomnolence and altered the pattern of SDB, thus improving gas exchange and oxygenation during sleep. Therefore, in selected patients with moderately severe obstructive sleep apnea, therapy with protriptyline is an alternative to surgical treatment with a tracheostomy.

Protriptyline in obstructive sleep apnea: a double-blind trial

We evaluated protriptyline, a nonsedating tricyclic antidepressant, as a treatment for obstructive sleep apnea in a double-blind crossover study of five men. After two weeks of treatment, with no change in body weight, daytime somnolence was markedly reduced and nocturnal oxygenation was improved, although apnea duration and frequency were not significantly decreased. Rapid-eye-movement (REM) stage time as a fraction of the total sleep time was reduced during treatment from 0.231 +/- 0.031 to 0.107 +/- 0.013 (mean +/- S.E.M.) (P less than 0.05). REM apnea time as a fraction of total sleep time was reduced from 0.145 +/- 0.022 to 0.054 +/- 0.006 (P less than 0.05). REM reduction during treatment with protriptyline can account for decreased REM apnea time. Similar decreases in REM stage time and REM apnea duration and similar improvement in oxygenation continued after six months of treatment. In addition, body weight, apnea, and arousal frequency were decreased at this time. Although the obstructive sleep apnea was not resolved, it was reduced. Protriptyline can be effective in patients with sleep apnea when the disorder is not life-threatening.

Central sleep apnea. Improvement with acetazolamide therapy

Respiratory rhythm during sleep may be dependent on blood pH with apneas being associated with alkalosis. Acidification may therefore have therapeutic value in some forms of sleep apnea. We administered acetazolamide to six patients with symptomatic central sleep apnea, a disorder of respiratory rhythm with little or no upper airway obstruction. Sleep studies were carried out before and after one week of drug therapy, during which time the mean arterial pH decreased from 7.42 to 7.34. All six patients had significant improvement, demonstrating a 69% reduction in total apneas. Five of the six patients reported better-quality sleep and decreased daytime hypersomnolence. Subsequent studies in normal subjects showed that acetazolamide, like other agents known to produce a metabolic acidosis, shifted the hypercapnic ventilatory response to the left 5 +/- 0.54 mm Hg. This may be important in mediating the observed decrease in apneas.

Sleep apnoea occurring only in REM (possible relevance of the case for some cot deaths)

A case of sleep apnoea occurring only within REM sleep in a 57-year-old man is described. It was successfully treated with clomipramine for a period. The patient probably had persistent phrenic nerve damage which accounted for, or contributed to, the phenomenon. It is suggested that this mechanism may operate in some cot deaths.

Protriptyline in the treatment of sleep apnoea

Nine patients with obstructive sleep apnoea were treated with 5 to 20 mg of protriptyline each night for two to 18 months. In four patients, there was dramatic, sustained improvement in symptoms and measured sleep quality and apnoea frequency and duration. There was no improvement in two patients and three developed intolerable side-effects preventing adequate treatment. Apnoea frequency was the only apparent predictor of responsiveness. Those with fewer than 30 episodes of apnoea per hour consistently improved. Only two of four patients with more than 60 episodes per hour improved. These results provide additional evidence that a carefully monitored trial of protriptyline may benefit selected patients with mild to moderate obstructive sleep apnoea.