PARLODEL- bromocriptine mesylate tablet
PARLODEL- bromocriptine mesylate capsule, gelatin coated
Validus Pharmaceuticals LLC
P a r l od e l ®
S n a pT a b s ®
(bromocriptine mesylate) ta b l e t s , U S P
(bromocriptine mesylate) ca p s u l e s , U S P
Parlodel® (bromocriptine mesylate) is an ergot derivative with potent dopamine receptor agonist activity. Each Parlodel® (bromocriptine mesylate) SnapTabs® tablet for oral administration contains 2½ mg and each capsule contains 5 mg bromocriptine (as the mesylate). Bromocriptine mesylate is chemically designated as Ergotaman-3′, 6′, 18-trione, 2-bromo-12′- hydroxy-2′- (1-methylethyl)-5′-(2-methylpropyl)-, (5′α)-monomethanesulfonate (salt).
The structural formula is:
2 ½ mg SnapTabs ®
Active Ingredient: bromocriptine mesylate, USP
Inactive Ingredients: colloidal silicon dioxide, lactose, magnesium stearate, maleic acid, povidone, starch, and another ingredient
5 mg Capsules
Active Ingredient: bromocriptine mesylate, USP
Inactive Ingredients: colloidal silicon dioxide, gelatin, lactose, magnesium stearate, red iron oxide, silicon dioxide, sodium lauryl sulfate, starch, maleic acid, titanium dioxide, yellow iron oxide, and another ingredient
Parlodel (bromocriptine mesylate) is a dopamine receptor agonist, which activates post-synaptic dopamine receptors. The dopaminergic neurons in the tuberoinfundibular process modulate the secretion of prolactin from the anterior pituitary by secreting a prolactin inhibitory factor (thought to be dopamine); in the corpus striatum the dopaminergic neurons are involved in the control of motor function. Clinically, Parlodel significantly reduces plasma levels of prolactin in patients with physiologically elevated prolactin as well as in patients with hyperprolactinemia. The inhibition of physiological lactation as well as galactorrhea in pathological hyperprolactinemic states is obtained at dose levels that do not affect secretion of other tropic hormones from the anterior pituitary. Experiments have demonstrated that bromocriptine induces long-lasting stereotyped behavior in rodents and turning behavior in rats having unilateral lesions in the substantia nigra. These actions, characteristic of those produced by dopamine, are inhibited by dopamine antagonists and suggest a direct action of bromocriptine on striatal dopamine receptors.
Bromocriptine mesylate is a nonhormonal, nonestrogenic agent that inhibits the secretion of prolactin in humans, with little or no effect on other pituitary hormones, except in patients with acromegaly, where it lowers elevated blood levels of growth hormone in the majority of patients.
Bromocriptine mesylate produces its therapeutic effect in the treatment of Parkinson’s disease, a clinical condition characterized by a progressive deficiency in dopamine synthesis in the substantia nigra, by directly stimulating the dopamine receptors in the corpus striatum. In contrast, levodopa exerts its therapeutic effect only after conversion to dopamine by the neurons of the substantia nigra, which are known to be numerically diminished in this patient population.
Following single dose administration of Parlodel tablets, 2 x 2.5 mg to 5 healthy volunteers under fasted conditions, the mean peak plasma levels of bromocriptine, time to reach peak plasma concentrations and elimination half-life were 465 pg/mL ± 226, 2.5 hrs ± 2 and 4.85 hr, respectively.1 Linear relationship was found between single doses of Parlodel and Cmax and AUC in the dose range of 1 to 7.5 mg.2 The pharmacokinetics of bromocriptine metabolites have not been reported.
Food did not significantly affect the systemic exposure of bromocriptine following administration of Parlodel tablets, 2.5 mg.3 It is recommended that Parlodel be taken with food because of the high percentage of subjects who vomit upon receiving bromocriptine under fasting conditions.
Following Parlodel 5 mg administered twice daily for 14 days, the bromocriptine Cmax and AUC at steady-state were 628 ± 375 pg/mL and 2377 ± 1186 pg*hr/mL, respectively.4
In vitro experiments showed that bromocriptine was 90% — 96% bound to serum albumin.
Bromocriptine undergoes extensive first-pass biotransformation, reflected by complex metabolite profiles and by almost complete absence of parent drug in urine and feces.
In vitro studies using human liver microsomes showed that bromocriptine has a high affinity for CYP3A and hydroxylations at the proline ring of the cyclopeptide moiety constituted a main metabolic pathway. 5 Inhibitors and/or potent substrates for CYP3A4 might therefore inhibit the clearance of bromocriptine and lead to increased levels. ( s ee PRECAUTIONS, drug interactions section). The participation of other major CYP enzymes such as 2D6, 2C8, and 2C19 on the metabolism of bromocriptine has not been evaluated. Bromocriptine is also an inhibitor of CYP3A4 with a calculated IC50 value of 1.69 μM.6 Given the low therapeutic concentrations of bromocriptine in patients (Cmax =0.82 nM), a significant alteration of the metabolism of a second drug whose clearance is mediated by CYP3A4 should not be expected. The potential effect of bromocriptine and its metabolites to act as inducers of CYP enzymes has not been reported.
About 82% and 5.6 % of the radioactive dose orally administered was recovered in feces and urine, respectively. Bromolysergic acid and bromoisolysergic acid accounted for half of the radioactivity in urine.5
1 Nelson, M. et. al. (1990). Pharmacokinetic evaluation of erythromycin and caffeine administered with bromocriptine. Clin Pharmacol Ther; 47(6):694-7.
2 Schran, H.F., Bhuta, S.I., Schwartz, et al. (1980). The pharmacokinetics of bromocriptine in man. In: Golstein, M. Calne, D.B.,et. Al (eds). Ergot compound and brain function: Neuroendocrine and neuropsychiatric aspects, pp. 125-139, New York, Rave Press.
3 Kopitar, Z., Vrhovac, B., Povsic, L., Plavsic, F., Francetic, I., Urbancic, J. (1991). The effect of food and metoclopramide on the pharmacokinetics and side effects of bromocriptine. Eur J Drug Metab Pharmacokinet; 16(3):177-81
4 Flogstad, A.K., Halse, J., Grass, P., Abisch, E., Djoseland, O., Kutz, K., Bodd, E., and Jervell, J., (1994). A comparison of octreotide, bromocriptine, or a combination of both drugs in acromegaly. Journal of Clinical Endocrinology & Metabolism; Vol 79, 461-465
5 Peyronneau MA, Delaforge M, Riviere R et al. 1994. High affinity of ergopeptides for CYP P450 3A. Importance of their peptide moiety for P450 recognition and hydroxylation of bromocriptine. Eur J Biochem 223:947-56.
6 Wynalda, M.A., Wienkers, L.C. (1997). Assessment of potential interactions between dopamine receptor agonists and various human cytochrome P450 enzymes using a simple in vitro inhibition screen. Drug Metab Dispos; 25:1211-14.
Effect of Renal Impairment
The effect of renal function on the pharmacokinetics of bromocriptine has not been evaluated.
Since parent drug and metabolites are almost completely excreted via metabolism, and only 6% eliminated via the kidney, renal impairment may not have a significant impact on the PK of bromocriptine and its metabolites ( s ee PRECAUTIONS, general).
Effect of Hepatic Impairment
The effect of liver impairment on the PK of Parlodel and its metabolites has not been evaluated. Since Parlodel is mainly eliminated by metabolism, liver impairment may increase the plasma levels of bromocriptine, therefore, caution may be necessary ( s ee PRECAUTIONS, general).
The effect of age, race, and gender on the pharmacokinetics of bromocriptine and its metabolites has not been evaluated.
In about 75% of cases of amenorrhea and galactorrhea, Parlodel therapy suppresses the galactorrhea completely, or almost completely, and reinitiates normal ovulatory menstrual cycles.
Menses are usually reinitiated prior to complete suppression of galactorrhea; the time for this on average is 6 to 8 weeks. However, some patients respond within a few days, and others may take up to 8 months.
Galactorrhea may take longer to control depending on the degree of stimulation of the mammary tissue prior to therapy. At least a 75% reduction in secretion is usually observed after 8 to 12 weeks. Some patients may fail to respond even after 12 months of therapy.
In many acromegalic patients, Parlodel produces a prompt and sustained reduction in circulating levels of serum growth hormone.
Parlodel Indications and Usage
Parlodel (bromocriptine mesylate) is indicated for the treatment of dysfunctions associated with hyperprolactinemia including amenorrhea with or without galactorrhea, infertility or hypogonadism. Parlodel treatment is indicated in patients with prolactin -secreting adenomas, which may be the basic underlying endocrinopathy contributing to the above clinical presentations. Reduction in tumor size has been demonstrated in both male and female patients with macroadenomas. In cases where adenectomy is elected, a course of Parlodel therapy may be used to reduce the tumor mass prior to surgery.
Parlodel therapy is indicated in the treatment of acromegaly. Parlodel therapy, alone or as adjunctive therapy with pituitary irradiation or surgery, reduces serum growth hormone by 50% or more in approximately ½ of patients treated, although not usually to normal levels.
Since the effects of external pituitary radiation may not become maximal for several years, adjunctive therapy with Parlodel offers potential benefit before the effects of irradiation are manifested.
Parlodel SnapTabs or capsules are indicated in the treatment of the signs and symptoms of idiopathic or postencephalitic Parkinson’s disease. As adjunctive treatment to levodopa (alone or with a peripheral decarboxylase inhibitor), Parlodel therapy may provide additional therapeutic benefits in those patients who are currently maintained on optimal dosages of levodopa, those who are beginning to deteriorate (develop tolerance) to levodopa therapy, and those who are experiencing “end of dose failure’’ on levodopa therapy. Parlodel therapy may permit a reduction of the maintenance dose of levodopa and, thus may ameliorate the occurrence and/or severity of adverse reactions associated with long-term levodopa therapy such as abnormal involuntary movements (e.g., dyskinesias) and the marked swings in motor function (“on-off” phenomenon). Continued efficacy of Parlodel therapy during treatment of more than 2 years has not been established.
Data are insufficient to evaluate potential benefit from treating newly diagnosed Parkinson’s disease with Parlodel. Studies have shown, however, significantly more adverse reactions (notably nausea, hallucinations, confusion and hypotension) in Parlodel-treated patients than in levodopa/carbidopa-treated patients. Patients unresponsive to levodopa are poor candidates for Parlodel therapy.
Hypersensitivity to bromocriptine or to any of the excipients of Parlodel (bromocriptine mesylate), uncontrolled hypertension and sensitivity to any ergot alkaloids. In patients being treated for hyperprolactinemia, Parlodel should be withdrawn when pregnancy is diagnosed ( s ee PRECAUTIONS, Hyperprolactinemic States). In the event that Parlodel is reinstituted to control a rapidly expanding macroadenoma ( s ee PRECAUTIONS, Hyperprolactinemic States) and a patient experiences a hypertensive disorder of pregnancy, the benefit of continuing Parlodel must be weighed against the possible risk of its use during a hypertensive disorder of pregnancy. When Parlodel is being used to treat acromegaly, prolactinoma, or Parkinson’s disease in patients who subsequently become pregnant, a decision should be made as to whether the therapy continues to be medically necessary or can be withdrawn. If it is continued, the drug should be withdrawn in those who may experience hypertensive disorders of pregnancy (including eclampsia, preeclampsia, or pregnancy-induced hypertension) unless withdrawal of Parlodel is considered to be medically contraindicated.
The drug should not be used during the postpartum period in women with a history of coronary artery disease and other severe cardiovascular conditions unless withdrawal is considered medically contraindicated. If the drug is used in the postpartum period, the patient should be observed with caution.
Since hyperprolactinemia with amenorrhea/galactorrhea and infertility has been found in patients with pituitary tumors, a complete evaluation of the pituitary is indicated before treatment with Parlodel (bromocriptine mesylate).
If pregnancy occurs during Parlodel administration, careful observation of these patients is mandatory. Prolactin-secreting adenomas may expand and compression of the optic or other cranial nerves may occur, emergency pituitary surgery becoming necessary. In most cases, the compression resolves following delivery. Reinitiation of Parlodel treatment has been reported to produce improvement in the visual fields of patients in whom nerve compression has occurred during pregnancy. The safety of Parlodel treatment during pregnancy to the mother and fetus has not been established.
Parlodel has been associated with somnolence, and episodes of sudden sleep onset, particularly in patients with Parkinson’s disease. Sudden onset of sleep during daily activities, in some cases without awareness or warning signs, has been reported. Patients must be informed of this and advised not to drive or operate machines during treatment with bromocriptine. Patients who have experienced somnolence and/or an episode of sudden sleep onset must not drive or operate machines. Furthermore, a reduction of dosage or termination of therapy may be considered.
Symptomatic hypotension can occur in patients treated with Parlodel for any indication. In postpartum studies with Parlodel, decreases in supine systolic and diastolic pressures of greater than 20 mm and 10 mm Hg, respectively, have been observed in almost 30% of patients receiving Parlodel. On occasion, the drop in supine systolic pressure was as much as 50-59 mm of Hg.
Since, especially during the first days of treatment, hypotensive reactions may occasionally occur and result in reduced alertness, particular care should be exercised when driving a vehicle or operating machinery.
While hypotension during the start of therapy with Parlodel occurs in some patients, in rare cases serious adverse events, including hypertension, myocardial infarction, seizures, stroke, have been reported in postpartum women treated with Parlodel for the inhibition of lactation. Hypertension have been reported, sometimes at the initiation of therapy, but often developing in the second week of therapy; seizures have also been reported both with and without the prior development of hypertension; stroke have been reported mostly in postpartum patients whose prenatal and obstetric courses had been uncomplicated. Many of these patients experiencing seizures (including cases of status epilepticus) and/or strokes reported developing a constant and often progressively severe headache hours to days prior to the acute event. Some cases of strokes and seizures were also preceded by visual disturbances (blurred vision, and transient cortical blindness). Cases of acute myocardial infarction have also been reported.
Although a causal relationship between Parlodel administration and hypertension, seizures, strokes, and myocardial infarction in postpartum women has not been established, use of the drug for prevention of physiological lactation, or in patients with uncontrolled hypertension is not recommended. In patients being treated for hyperprolactinemia, Parlodel should be withdrawn when pregnancy is diagnosed ( s ee PRECAUTIONS, Hyperprolactinemic States). In the event that Parlodel is reinstituted to control a rapidly expanding macroadenoma ( s ee PRECAUTIONS, Hyperprolactinemic States) and a patient experiences a hypertensive disorder of pregnancy, the benefit of continuing Parlodel must be weighed against the possible risk of its use during a hypertensive disorder of pregnancy. When Parlodel is being used to treat acromegaly or Parkinson’s disease in patients who subsequently become pregnant, a decision should be made as to whether the therapy continues to be medically necessary or can be withdrawn. If it is continued, the drug should be withdrawn in those who may experience hypertensive disorders of pregnancy (including eclampsia, preeclampsia, or pregnancy-induced hypertension) unless withdrawal of Parlodel is considered to be medically contraindicated. Because of the possibility of an interaction between Parlodel and other ergot alkaloids, the concomitant use of these medications is not recommended. Periodic monitoring of the blood pressure, particularly during the first weeks of therapy is prudent. If hypertension, severe, progressive, or unremitting headache (with or without visual disturbance), or evidence of CNS toxicity develops, drug therapy should be discontinued and the patient should be evaluated promptly. Particular attention should be paid to patients who have recently been treated or are on concomitant therapy with drugs that can alter blood pressure. Their concomitant use in the puerperium is not recommended.
Among patients on Parlodel, particularly on long-term and high-dose treatment, pleural and pericardial effusions, as well as pleural and pulmonary fibrosis and constrictive pericarditis, have been reported. Patients with unexplained pleuropulmonary disorders should be examined thoroughly and discontinuation of Parlodel therapy should be considered. In those instances in which Parlodel treatment was terminated, the changes slowly reverted towards normal.
In a few patients on Parlodel, particularly on long-term and high-dose treatment, retroperitoneal fibrosis has been reported. To ensure recognition of retroperitoneal fibrosis at an early reversible stage it is recommended that its manifestations (e.g., back pain, edema of the lower limbs, impaired kidney function) should be watched in this category of patients. Parlodel medication should be withdrawn if fibrotic changes in the retroperitoneum are diagnosed or suspected.
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