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Pre-Marketing Clinical Trial Experience

The specific adverse event data described in this section are based on studies of the immediate-release tablet formulation. In clinical trials, once-daily treatment with RAZADYNE® ER (galantamine hydrobromide) Extended-Release Capsules was well tolerated and adverse events were similar to those seen with RAZADYNE® Tablets.

Adverse Events Leading to Discontinuation

In two large scale, placebo-controlled trials of 6 months duration in which patients were titrated weekly from 8 to 16 to 24, and to 32 mg/day, the risk of discontinuation because of an adverse event in the galantamine group exceeded that in the placebo group by about threefold. In contrast, in a 5-month trial with escalation of the dose by 8 mg/day every 4 weeks, the overall risk of discontinuation because of an adverse event was 7%, 7%, and 10% for the placebo, galantamine 16 mg/day, and galantamine 24 mg/day groups, respectively, with gastrointestinal adverse effects the principle reason for discontinuing galantamine. Table 1 shows the most frequent adverse events leading to discontinuation in this study.

Table 1: Most Frequent Adverse Events Leading to Discontinuation in a Placebo-Controlled, Double-Blind Trial With a 4-Week Dose Escalation Schedule

Adverse Events Reported in Controlled Trials

The reported adverse events in trials using RAZADYNE® (galantamine hydrobromide) Tablets reflect experience gained under closely monitored conditions in a highly selected patient population. In actual practice or in other clinical trials, these frequency estimates may not apply, as the conditions of use, reporting behavior and the types of patients treated may differ.

The majority of these adverse events occurred during the dose-escalation period. In those patients who experienced the most frequent adverse event, nausea, the median duration of the nausea was 5-7 days.

Administration of RAZADYNE® with food, the use of anti-emetic medication, and ensuring adequate fluid intake may reduce the impact of these events.

The most frequent adverse events, defined as those occurring at a frequency of at least 5% and at least twice the rate on placebo with the recommended maintenance dose of either 16 or 24 mg/day of RAZADYNE® under conditions of every 4-week dose-escalation for each dose increment of 8 mg/day, are shown in Table 2. These events were primarily gastrointestinal and tended to be less frequent with the 16 mg/day recommended initial maintenance dose.

Table 2: The Most Frequent Adverse Events in the Placebo-Controlled Trial With Dose Escalation Every 4 Weeks Occurring in at Least 5% of Patients Receiving RAZADYNE® and at Least Twice the Rate on Placebo.

Table 3: The most common adverse events (adverse events occurring with an incidence of at least 2% with RAZADYNE® treatment and in which the incidence was greater than with placebo treatment) are listed in Table 3 for four placebo-controlled trials for patients treated with 16 or 24 mg/day of RAZADYNE® .

Table 3: Adverse Events Reported in at Least 2% of Patients With Alzheimer's Disease Administered RAZADYNE® and at a Frequency Greater Than With Placebo

Adverse events occurring with an incidence of at least 2% in placebo-treated patients that was either equal to or greater than with RAZADYNE® treatment were constipation, agitation, confusion, anxiety, hallucination, injury, back pain, peripheral edema, asthenia, chest pain, urinary incontinence, upper respiratory tract infection, bronchitis, coughing, hypertension, fall, and purpura.

There were no important differences in adverse event rates related to dose or sex. There were too few non-Caucasian patients to assess the effects of race on adverse event rates.

No clinically relevant abnormalities in laboratory values were observed.

Other Adverse Events Observed During Clinical Trials

RAZADYNE® Tablets were administered to 3055 patients with Alzheimer's disease. A total of 2357 patients received galantamine in placebo-controlled trials and 761 patients with Alzheimer's disease received galantamine 24 mg/day, the maximum recommended maintenance dose. About 1000 patients received galantamine for at least one year and approximately 200 patients received galantamine for two years.

To establish the rate of adverse events, data from all patients receiving any dose of galantamine in 8 placebo-controlled trials and 6 open-label extension trials were pooled. The methodology to gather and codify these adverse events was standardized across trials, using WHO terminology. All adverse events occurring in approximately 0.1% are included, except for those already listed elsewhere in labeling, WHO terms too general to be informative, or events unlikely to be drug caused. Events are classified by body system and listed using the following definitions: frequent adverse events - those occurring in at least 1/100 patients; infrequent adverse events - those occurring in 1/100 to 1/1000 patients; rare adverse events - those occurring in fewer than 1/1000 patients. These adverse events are not necessarily related to RAZADYNE® treatment and in most cases were observed at a similar frequency in placebo-treated patients in the controlled studies. Additional adverse events observed in other clinical trials are also included below.

Body As a Whole – General Disorders: Frequent: chest pain, asthenia, fever, malaise

Cardiovascular System Disorders: Infrequent: postural hypotension, hypotension, dependent edema, cardiac failure, myocardial ischemia or infarction

Central & Peripheral Nervous System Disorders: Infrequent: vertigo, hypertonia, convulsions, involuntary muscle contractions, paresthesia, ataxia, hypokinesia, hyperkinesia, apraxia, aphasia, leg cramps, tinnitus, transient ischemic attack or cerebrovascular accident

Gastrointestinal System Disorders: Frequent: flatulence; Infrequent: gastritis, melena, dysphagia, rectal hemorrhage, dry mouth, saliva increased, diverticulitis, gastroenteritis, hiccup; Rare: esophageal perforation

Heart Rate & Rhythm Disorders: Infrequent: AV block, palpitation, atrial arrhythmias including atrial fibrillation and supraventricular tachycardia, QT prolonged, bundle branch block, T-wave inversion, ventricular tachycardia; Rare: severe bradycardia

Metabolic & Nutritional Disorders: Infrequent: hyperglycemia, alkaline phosphatase increased

Platelet, Bleeding & Clotting Disorders: Infrequent: purpura, epistaxis, thrombocytopenia

Psychiatric Disorders: Infrequent: apathy, paroniria, paranoid reaction, libido increased, delirium; Rare: suicidal ideation, suicide

Urinary System Disorders: Frequent: incontinence; Infrequent: hematuria, micturition frequency, cystitis, urinary retention, nocturia, renal calculi

Post-Marketing Experience

Other adverse events from post-approval controlled and uncontrolled clinical trials and post-marketing experience observed in patients treated with RAZADYNE® include:

Body as a Whole – General Disorders: dehydration (including rare, severe cases leading to renal insufficiency and renal failure)

Psychiatric Disorders: aggression

Gastrointestinal System Disorders: upper and lower GI bleeding

Hepatobiliary Disorders: elevated liver enzymes, hepatitis

Metabolic & Nutritional Disorders: hypokalemia

These adverse events may or may not be causally related to the drug.

(see also CLINICAL PHARMACOLOGY, Drug-Drug Interactions)

Use with Anticholinergics

RAZADYNE® has the potential to interfere with the activity of anticholinergic medications.

Use With Cholinomimetics and Other Cholinesterase Inhibitors

A synergistic effect is expected when cholinesterase inhibitors are given concurrently with succinylcholine, other cholinesterase inhibitors, similar neuromuscular blocking agents or cholinergic agonists such as bethanechol.

Effect of Other Drugs on Galantamine

In vitro

CYP3A4 and CYP2D6 are the major enzymes involved in the metabolism of galantamine. CYP3A4 mediates the formation of galantamine-N-oxide; CYP2D6 leads to the formation of Odesmethyl-galantamine. Because galantamine is also glucuronidated and excreted unchanged, no single pathway appears predominant.

In vivo

Cimetidine and Ranitidine: Galantamine was administered as a single dose of 4 mg on day 2 of a 3-day treatment with either cimetidine (800 mg daily) or ranitidine (300 mg daily). Cimetidine increased the bioavailability of galantamine by approximately 16%. Ranitidine had no effect on the PK of galantamine.

Ketoconazole: Ketoconazole, a strong inhibitor of CYP3A4 and an inhibitor of CYP2D6, at a dose of 200 mg BID for 4 days, increased the AUC of galantamine by 30%.

Erythromycin: Erythromycin, a moderate inhibitor of CYP3A4 at a dose of 500 mg QID for 4 days, affected the AUC of galantamine minimally (10% increase).

Paroxetine: Paroxetine, a strong inhibitor of CYP2D6, at 20 mg/day for 16 days, increased the oral bioavailability of galantamine by about 40%.

Memantine: Memantine, an N-methyl-D-aspartate receptor antagonist, at a dose of 10 mg BID, had no effect on the pharmacokinetics of galantamine (16 mg/day) at steady state.

Effect of Galantamine on Other Drugs

In vitro

Galantamine did not inhibit the metabolic pathways catalyzed by CYP1A2, CYP2A6, CYP3A4, CYP4A, CYP2C, CYP2D6 or CYP2E1. This indicates that the inhibitory potential of galantamine towards the major forms of cytochrome P450 is very low.

In vivo

Warfarin: Galantamine at 24 mg/day had no effect on the pharmacokinetics of R- and S-warfarin (25 mg single dose) or on the prothrombin time. The protein binding of warfarin was unaffected by galantamine.

Digoxin: Galantamine at 24 mg/day had no effect on the steady-state pharmacokinetics of digoxin (0.375 mg once daily) when they were coadministered. In this study, however, one healthy subject was hospitalized for 2^nd and 3^rd degree heart block and bradycardia.

Last reviewed on RxList: 3/14/2012
This monograph has been modified to include the generic and brand name in many instances.