Adverse Reactions from Clinical Trials
The incidence of adverse effects is quite high (69%) but these are generally mild to moderate in degree. Therapy was discontinued in approximately 5% of patients because of adverse effects. These in decreasing order of frequency are: nausea (49%), headache (19%), dizziness (17%), fatigue (7%), lightheadedness (5%), vomiting (5%), abdominal cramps (4%), nasal congestion (3%), constipation (3%), diarrhea (3%) and drowsiness (3%).
A slight hypotensive effect may accompany Parlodel® (bromocriptine mesylate) treatment. The occurrence of adverse reactions may be lessened by temporarily reducing dosage to ½ SnapTabs® tablet 2 or 3 times daily. A few cases of cerebrospinal fluid rhinorrhea have been reported in patients receiving Parlodel for treatment of large prolactinomas. This has occurred rarely, usually only in patients who have received previous transsphenoidal surgery, pituitary radiation, or both, and who were receiving Parlodel for tumor recurrence. It may also occur in previously untreated patients whose tumor extends into the sphenoid sinus.
The most frequent adverse reactions encountered in acromegalic patients treated with Parlodel were: nausea (18%), constipation (14%), postural/orthostatic hypotension (6%), anorexia (4%), dry mouth/nasal stuffiness (4%), indigestion/dyspepsia (4%), digital vasospasm (3%), drowsiness/tiredness (3%) and vomiting (2%).
Less frequent adverse reactions (less than 2%) were: gastrointestinal bleeding, dizziness, exacerbation of Raynaud's syndrome, headache and syncope. Rarely (less than 1%) hair loss, alcohol potentiation, faintness, lightheadedness, arrhythmia, ventricular tachycardia, decreased sleep requirement, visual hallucinations, lassitude, shortness of breath, bradycardia, vertigo, paresthesia, sluggishness, vasovagal attack, delusional psychosis, paranoia, insomnia, heavy headedness, reduced tolerance to cold, tingling of ears, facial pallor and muscle cramps have been reported.
In clinical trials in which Parlodel was administered with concomitant reduction in the dose of levodopa/carbidopa, the most common newly appearing adverse reactions were: nausea, abnormal involuntary movements, hallucinations, confusion, “on-off'' phenomenon, dizziness, drowsiness, faintness/fainting, vomiting, asthenia, abdominal discomfort, visual disturbance, ataxia, insomnia, depression, hypotension, shortness of breath, constipation, and vertigo.
Less common adverse reactions which may be encountered include: anorexia, anxiety, blepharospasm, dry mouth, dysphagia, edema of the feet and ankles, erythromelalgia, epileptiform seizure, fatigue, headache, lethargy, mottling of skin, nasal stuffiness, nervousness, nightmares, paresthesia, skin rash, urinary frequency, urinary incontinence, urinary retention, and rarely, signs and symptoms of ergotism such as tingling of fingers, cold feet, numbness, muscle cramps of feet and legs or exacerbation of Raynaud's syndrome.
Abnormalities in laboratory tests may include elevations in blood urea nitrogen, SGOT, SGPT, GGPT, CPK, alkaline phosphatase and uric acid, which are usually transient and not of clinical significance.
Adverse Reactions from Postmarketing Experience
The following adverse reactions have been reported during postapproval use of Parlodel (All Indications Combined). Because adverse reactions from spontaneous reports are reported voluntarily from a population of uncertain size, it is generally not possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Psychiatric disorders: Confusion, psychomotor agitation/excitation, hallucinations, psychotic disorders, insomnia, libido increase, hypersexuality.
Nervous system disorders: Headache, drowsiness, dizziness, dyskinaesia, somnolence, paraesthesia, excess daytime somnolence, sudden onset of sleep.
Eye disorders: Visual disturbance, vision blurred.
Ear and labyrinth disorders: Tinnitus.
Cardiac disorders: Pericardial effusion, constrictive pericarditis, tachycardia, bradycardia, arrhythmia, cardiac valve fibrosis.
Vascular disorders: Hypotension, orthostatic hypotension (very rarely leading to syncope), reversible pallor of fingers and toes induced by cold (especially in patients with history of Raynaud's phenomenon)
Respiratory, thoracic and mediastinal disorders: Nasal congestion, pleural effusion, pleural fibrosis, pleurisy, pulmonary fibrosis, dyspnoea.
Gastrointestinal disorders: Nausea, constipation, vomiting, dry mouth, diarrhoea, abdominal pain, retroperitoneal fibrosis, gastrointestinal ulcer, gastrointestinal haemorrhage.
Skin and subcutaneous tissue disorders: Allergic skin reactions, hair loss.
Musculoskeletal and connective tissue disorders: Leg cramps.
General disorders and administration site conditions: Fatigue, peripheral edema, a syndrome resembling Neuroleptic Malignant Syndrome on abrupt withdrawal of Parlodel (See PRECAUTIONS).
Adverse Events Observed in Other Conditions
(see above WARNINGS)
In postpartum studies with Parlodel, 23 percent of postpartum patients treated had at least 1 side effect, but they were generally mild to moderate in degree. Therapy was discontinued in approximately 3% of patients. The most frequently occurring adverse reactions were: headache (10%), dizziness (8%), nausea (7%), vomiting (3%), fatigue (1.0%), syncope (0.7%), diarrhea (0.4%) and cramps (0.4%). Decreases in blood pressure ( ≥ 20 mm Hg systolic and ≥ 10 mm Hg diastolic) occurred in 28% of patients at least once during the first 3 postpartum days; these were usually of a transient nature. Reports of fainting in the puerperium may possibly be related to this effect. In postmarketing experience in the U.S., serious adverse reactions reported include 72 cases of seizures (including 4 cases of status epilepticus), 30 cases of stroke, and 9 cases of myocardial infarction among postpartum patients. Seizure cases were not necessarily accompanied by the development of hypertension. An unremitting and often progressively severe headache, sometimes accompanied by visual disturbance, often preceded by hours to days many cases of seizure and/or stroke. Most patients had shown no evidence of any of the hypertensive disorders of pregnancy including eclampsia, preeclampsia or pregnancy-induced hypertension. One stroke case was associated with sagittal sinus thrombosis, and another was associated with cerebral and cerebellar vasculitis. One case of myocardial infarction was associated with unexplained disseminated intravascular coagulation and a second occurred in conjunction with use of another ergot alkaloid. The relationship of these adverse reactions to Parlodel administration has not been established.
In rare cases serious adverse events, including hypertension, myocardial infarction, seizures, stroke, or psychic disorders have been reported in postpartum women treated with Parlodel. In some patients the development of seizures or stroke was preceded by severe headache and/or transient visual disturbances. Although the causal relationship of these events to the drug is uncertain, periodic monitoring of blood pressure is advisable in postpartum women receiving Parlodel. If hypertension, severe, progressive, or unremitting headache (with or without visual disturbances), or evidence of CNS toxicity develop, the administration of Parlodel should be discontinued and the patient should be evaluated promptly.
Particular caution is required in patients who have recently been treated or are on concomitant therapy with drugs that can alter blood pressure, e.g. vasoconstrictors such as sympathomimetics or ergot alkaloids including ergometrine or methylergometrine and their concomitant use in the puerperium is not recommended.