Increased thyrotrophin and prolactin secretion induced by domperidone in hypothyroid subjects

Dose-effect study of domperidone as a galactagogue in preterm mothers with insufficient milk supply, and its transfer into milk

AIMS

To investigate the possibility of a dose-response relationship for the use of domperidone in treating insufficient milk supply in mothers of preterm infants, and to quantify the exposure of the breastfed infant to domperidone.

METHODS

Six preterm mothers received domperidone (30 mg daily or 60 mg daily) in a double-blind, randomized, crossover trial. Milk production and serum prolactin were measured before and during the trial, and domperidone concentration in milk was measured during drug treatment.

RESULTS

For milk production, two of the mothers were 'nonresponders', whereas the other four were 'responders' and showed a significant increase in milk production from 8.7 +/- 3.1 g h(-1) in the run-in phase (mean +/- SEM), 23.6 +/- 3.9 g h(-1) for the 30-mg dose (P = 0.0217) and 29.4 +/- 6.6 g h(-1) for the 60-mg dose (P = 0.0047). In all participants, serum prolactin was significantly increased for both doses, but the response was not dose dependent. Median (interquartile range) domperidone concentrations in milk over a dose interval at steady-state were 0.28 microg l(-1) (0.24-0.43) and 0.49 microg l(-1) (0.33-0.72) for the 30-mg and 60-mg doses, respectively. The mean relative infant dose was 0.012% at 30 mg daily and 0.009% at 60 mg daily.

CONCLUSION

In one-third of mothers, domperidone did not increase milk production. In the remainder, milk production increased at both domperidone doses, and there was a trend for a dose-response relationship. The amount of domperidone that transfers into milk was extremely low, and infant exposure via breastfeeding was not considered to be significant.

Domperidone: a peripherally acting dopamine2-receptor antagonist

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, and safety of domperidone in the treatment of gastrointestinal motility disorders and emesis.

DATA SOURCES

MEDLINE and Excerpta Medica online databases were searched to identify published reports.

STUDY SELECTION

Domperidone has been marketed worldwide outside the US since 1978, and extensive clinical data for this drug are available. This review focuses on the clinical experience from controlled studies of domperidone in the treatment of motility disorders, particularly diabetic gastroparesis. Also, case reports are used in summarizing safety. The control comparator groups included placebo or other prokinetic drugs (metoclopramide and cisapride). Controlled clinical trials of domperidone's efficacy and safety as an antiemetic are also briefly examined. Although a variety of domperidone dosage forms have been marketed, data generated from trials using the 10-mg tablet are highlighted because this is the only dosage form available in Canada and is under investigation in the US.

DATA EXTRACTION

Because symptoms do not correlate with objective measures of gastrointestinal motility and they are the primary reason that patients with motility disorders seek treatment, the primary outcome extracted from the clinical studies was symptomatic response to treatment. Safety and efficacy between domperidone and placebo, metoclopramide, or cisapride were compared.

DATA SYNTHESIS

Domperidone, a peripheral dopamine2-receptor antagonist, regulates the motility of gastric and small intestinal smooth muscle and has been shown to have some effects on the motor function of the esophagus. It also has antiemetic activity as a result of blockade of dopamine receptors in the chemoreceptor trigger zone. In controlled clinical trials, domperidone provided better relief of symptoms (anorexia, nausea, vomiting, abdominal pain, early satiety, bloating, distension) than placebo in patients with symptoms of diabetic gastropathy; symptomatic improvement was similar with domperidone and metoclopramide or cisapride. Domperidone also provided short-term relief of symptoms in patients with dyspepsia or gastroesophageal reflux, prevented nausea and vomiting associated with emetogenic chemotherapy, and prevented the gastrointestinal and emetic adverse effects of antiparkinsonian drugs. Because very little domperidone crosses the blood-brain barrier, reports of central nervous system adverse effects, such as dystonic reactions, are rare.

CONCLUSIONS

Domperidone is a unique gastrokinetic and antiemetic drug. Because of its favorable safety profile, domperidone appears to be an attractive alternative to metoclopramide. In the management of diabetic gastropathy, domperidone's antiemetic activity distinguishes it from cisapride.

Alterations in pituitary GnRH and dopamine receptors associated with the seasonal variation and regulation of gonadotropin release in the goldfish (Carassius auratus)

Seasonal variations in the serum concentrations of gonadotropin (GtH) and the serum GtH response to intraperitoneal injection of domperidone, a specific dopamine receptor antagonist, were examined in goldfish. In addition, the effects of in vivo treatment of goldfish with a superactive analog of salmon gonadotropin-releasing hormone (sGnRH-A) and domperidone on the binding parameters of pituitary GnRH and dopamine receptors were investigated in goldfish. Serum concentrations of GtH and the maximum GtH response to domperidone increased in correlation with advancing gonadal maturation; values increased from those in sexually regressed fish in January to maximal levels observed in fish in late stages of gonadal recrudescence in March, followed by a decrease with gonadal regression. At all stages, injection of domperidone increased serum concentrations of GtH in a dose-related manner; however, the ED50 of domperidone did not vary significantly over the course of the reproductive cycle. Multiple injections of sGnRH-A caused a progressively increasing and more prolonged serum GtH response; as well, multiple sGnRH-A treatment significantly potentiated the serum GtH response to domperidone without altering the ED50 of domperidone. sGnRH-A treatment caused a significant increase in the number of dopamine/neuroleptic receptors in the goldfish pars distalis, accompanied by a nonsignificant increase in dopamine/neuroleptic receptors in the neurointermediate lobe, and significantly increased the number of high-affinity GnRH receptors in the goldfish pituitary. Treatment with domperidone also significantly increased pituitary high-affinity GnRH receptor numbers. Receptor affinities were not significantly altered by either sGnRH-A or domperidone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased serum prolactin but normal TSH during prolonged domperidone treatment in children

The influence of the dopamine receptor blocking agent domperidone on prolactin and TSH secretion was studied in 16 infants, aged 10-360 days, who were treated for gastroesophageal reflux. The pretreatment serum prolactin levels were not statistically different from the levels in age-matched controls and showed the well-known inverse relationship with age. During treatment with domperidone a significant increase in prolactin level was observed on days 1, 4 and 21-28, the mean values on these three days not being statistically different. No correlation could be found between the serum prolactin levels and the corresponding plasma domperidone levels. One infant of this series and three not included in this series developed reversible breast hypertrophy with galactorrhoea in three of them: in none of them was the prolactin level, corrected for age, above 1 SD of the mean. All had received relatively high doses of domperidone. In 13 patients domperidone did not influence TSH secretion.

TRH: pathophysiologic and clinical implications

Thyrotropin releasing hormone is thought to be a tonic stimulator of the pituitary TSH secretion regulating the setpoint of the thyrotrophs to the suppressive effect of thyroid hormones. The peptide stimulates the release of normal and elevated prolactin. ACTH and GH may increase in response to exogenous TRH in pituitary ACTH and GH hypersecretion syndromes and in some extrapituitary diseases. The pathophysiological implications of extrahypothalamic TRH in humans are essentially unknown. The TSH response to TRH is nowadays widely used as a diagnostic amplifier in thyroid diseases being suppressed in borderline and overt hyperthyroid states and increased in primary thyroid failure. In hypothyroid states of hypothalamic origin, TSH increases in response to exogenous TRH often with a delayed and/or exaggerated time course. But in patients with pituitary tumors and suprasellar extension TSH may also respond to TRH despite secondary hypothyroidism. This TSH increase may indicate a suprasellar cause for the secondary hypothyroidism, probably due to portal vessel occlusion. The TSH released in these cases is shown to be biologically inactive.

Domperidone. A review of its pharmacological activity, pharmacokinetics and therapeutic efficacy in the symptomatic treatment of chronic dyspepsia and as an antiemetic

Domperidone is a dopamine antagonist that does not readily enter the central nervous system. Given parenterally or orally it increases gastric emptying of liquids and increases lower oesophageal sphincter pressure in healthy subjects. The antiemetic and pharmacodynamic profile of domperidone is similar to that of metoclopramide, although domperidone has a lower propensity to cause extrapyramidal side effects. Domperidone effectively alleviates symptoms of chronic postprandial dyspepsia and nausea and vomiting due to a wide variety of underlying causes and in some studies has been superior to metoclopramide. Vomiting associated with the administration of moderately emetic cytotoxic drugs is controlled in the majority of patients. Alleviation of the dose-limiting peripheral side effects (nausea and vomiting) of the anti-Parkinsonian drugs bromocriptine and levodopa, enables a higher optimum dose, with consequent improvement in Parkinsonian symptoms. Domperidone does not aggravate the extrapyramidal side effects of neuroleptic drugs. Control of cytotoxic-induced, and postprandial nausea and vomiting in children has been achieved with domperidone without evidence of extrapyramidal side effects. Indeed, side effects have seldom occurred with therapeutic doses of domperidone.

Domperidone. A review of its pharmacological activity, pharmacokinetics and therapeutic efficacy in the symptomatic treatment of chronic dyspepsia and as an antiemetic

Domperidone is a dopamine antagonist that does not readily enter the central nervous system. Given parenterally or orally it increases gastric emptying of liquids and increases lower oesophageal sphincter pressure in healthy subjects. The antiemetic and pharmacodynamic profile of domperidone is similar to that of metoclopramide, although domperidone has a lower propensity to cause extrapyramidal side effects. Domperidone effectively alleviates symptoms of chronic postprandial dyspepsia and nausea and vomiting due to a wide variety of underlying causes and in some studies has been superior to metoclopramide. Vomiting associated with the administration of moderately emetic cytotoxic drugs is controlled in the majority of patients. Alleviation of the dose-limiting peripheral side effects (nausea and vomiting) of the anti-Parkinsonian drugs bromocriptine and levodopa, enables a higher optimum dose, with consequent improvement in Parkinsonian symptoms. Domperidone does not aggravate the extrapyramidal side effects of neuroleptic drugs. Control of cytotoxic-induced, and postprandial nausea and vomiting in children has been achieved with domperidone without evidence of extrapyramidal side effects. Indeed, side effects have seldom occurred with therapeutic doses of domperidone.