Abstract
Domperidone is a prokinetic drug used for diabetic gastro paresis, hiccoughs, and vomiting. It is a peripheral D2 receptor antagonist with selective peripheral activity restricted to the upper gastro intestinal tract. It is not known to cross the blood brain barrier and hence, lacks neurological side effects. We would like to report a case of domperidone induced galactorrhea in a young female who presented with galactorrhea and other symptoms suggestive of prolactinoma.
KEY WORDS: Domperidone, drug induced galactorrhea, galactorrhea, prolactin
Introduction
Domperidone is a peripheral D2 antagonist which is commonly used for the treatment of symptoms such as vomiting, gastro paresis, and hiccoughs. As it has preferential action on the D2 receptors of the upper gastrointestinal tract, neurological side effects, and hyperprolactinemia are rarely reported. Stomach cramps, diarrhea, constipation, mastalgia, are the rarer side effects which have been observed. We report a case of domperidone induced hyperprolactinemia and galactorrhea in a young female.
Case Report
A 19 year old married housewife with no premorbidities came with chief complaints of bilateral mastalgia and galactorrhea since the past one week. Patient had been suffering from irregular menstruation since, the past six months for which no treatment was taken. Her last menstrual period was 43 days prior to the episode. She was suffering from fever, dysuria, vomiting in the week prior, for which she had taken ciprofloxacin at the dose of 500 mg twice a day for 5 days. She took oral domperidone 10 mg thrice a day for 5 days for her vomiting and galactorrhea developed on the sixth day. There was no history of increase in breast size. She also gave history of intermittent headache since 3 months. On examination, other than breast tenderness and galactorrhea there were no other findings. Field of vision was normal. Prolactin level was done using enzyme immune assay which was elevated (100.5 ng/ml). Routine investigations including liver, renal, and thyroid function tests (other causes of hyperprolactinemia) were within normal limits. In view of headache, formal perimetry and MRI brain including pituitary was done which was normal. Urine pregnancy tests were repeatedly negative. A repeat prolactin done after 5 days was 9.7 ng/ml which was within normal limits. As other causes of hyperprolactinemia were ruled out, it was ascertained that the oral domperidone could be the culprit in this situation. Causality assessment was carried out using the Naranjo's causality assessment scale which showed highly probable causal association.
Discussion
Domperidone is a dopaminergic (D2) receptor antagonist with peripheral activity restricted to the upper gastro intestinal tract. It has several inhibitory effects on motility, including reduction of lower esophageal sphincter and intragastric pressures. These effects result from suppression of acetylcholine release from myenteric motor neurons by antagonizing the inhibitory effect of dopamine on these neurons. Dopamine receptor antagonists such as metoclopramide and domperidone are effective as prokinetic agents.
The drug is absorbed orally with high bioavailability. It undergoes hepatic and intestinal first pass metabolism. The T½ of the drug is around 7-12 hours and undergoes predominant renal excretion. In contrast to metaclopramide, domperidone predominantly antagonizes the D2 receptor without major involvement of other receptors. It has lower ceiling anti-emetic and prokinetic actions in doses of 10-20 mg thrice a day. Domperidone does not readily cross the blood-brain barrier to cause extra pyramidal side effects, yet exerts effects in the parts of the central nervous system that lack this barrier, such as those regulating emesis (chemoreceptor trigger zone), temperature etc. Extra pyramidal syndromes and hyperprolactinemia have been reported rarely. Stomach cramps, diarrhea, constipation, mastalgia, are the other side effects which have been observed occasionally.[1]
One of the first reports on domperidone induced galactorrhea was from Great Britain in 1983.[2] Another was from India in 1991.[3] Gynaecomastia has been reported, more in case of non-specific D2 antagonists such as metoclopramide. This was noted in a male infant associated with renal failure (renal failure contributory to the hyperprolactinemia).[4]
A study was conducted to compare the effects of domperidone and metoclopramide on prolactin secretion in women. It was found that nulliparous women showed highest response with drug intake as compared to multiparous women who showed the same response to various doses of the same drug.[5]
Conclusion
Domperidone is a drug used on a daily basis for relief of common problems. Galactorrhea is an adverse drug reaction not commonly encountered. Hence, physicians should be aware of such uncommon side effects of common drugs to avert unnecessary worry and intervention.
Footnotes
Source of Support: Nil
Conflict of Interest: None declared
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