Continue the starting dose for at least one week and then titrate to reduce and maintain the platelet count below 600,000/µL, and ideally between 150,000/µL and 400,000/µL. The dose increment should not exceed 0.5 mg/day in any one week. Dosage should not exceed 10 mg/day or 2.5 mg in a single dose. Most patients will experience an adequate response at a dose of 1.5 to 3.0 mg/day. Monitor platelet counts weekly during titration then monthly or as necessary.

AGRYLIN therapy requires clinical monitoring, including complete blood counts, assessment of hepatic and renal function, and electrolytes.

To prevent the occurrence of thrombocytopenia, monitor platelet counts every two days during the first week of treatment and at least weekly thereafter until the maintenance dosage is reached. Typically, platelet counts begin to respond within 7 to 14 days at the proper dosage. In the clinical trials, the time to complete response, defined as platelet count ≤600,000/µL, ranged from 4 to 12 weeks. In the event of dosage interruption or treatment withdrawal, the rebound in platelet count is variable, but platelet counts typically will start to rise within 4 days and return to baseline levels in one to two weeks, possibly rebounding above baseline values. Monitor platelet counts frequently.

Torsades de pointes and ventricular tachycardia have been reported with AGRYLIN. Obtain a pre-treatment cardiovascular examination including an ECG in all patients. During treatment with AGRYLIN monitor patients for cardiovascular effects and evaluate as necessary.

Hepatic impairment increases anagrelide exposure and could increase the risk of QTc prolongation. Monitor patients with hepatic impairment for QTc prolongation and other cardiovascular adverse reactions. The potential risks and benefits of AGRYLIN therapy in a patient with mild and moderate hepatic impairment should be assessed before treatment is commenced. Reduce AGRYLIN dose in patients with moderate hepatic impairment. Avoid use of AGRYLIN in patients with severe hepatic impairment.

In patients with cardiac disease, use AGRYLIN only when the benefits outweigh the risks.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The following adverse reactions have been identified during post-marketing use of AGRYLIN. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Other adverse reactions in pediatric patients reported in spontaneous reports and literature reviews include:

Monitor patients for bleeding, particularly those receiving concomitant therapy with other drugs known to cause bleeding (e.g., anticoagulants, PDE3 inhibitors, NSAIDs, antiplatelet agents, selective serotonin reuptake inhibitors).

Of the 942 subjects in clinical studies of AGRYLIN, 42.1% were 65 years and over, while 14.9% were 75 years and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in response between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

The precise mechanism by which anagrelide reduces blood platelet count is unknown. In cell culture studies, anagrelide suppressed expression of transcription factors including GATA-1 and FOG-1 required for megakaryocytopoiesis, ultimately leading to reduced platelet production.

Dose proportionality has been found in the dose range 0.5 mg to 2.5 mg.

In a two-year rat carcinogenicity study a higher incidence of uterine adenocarcinoma, relative to controls, was observed in females receiving 30 mg/kg/day (at least 174 times human AUC exposure after a 1 mg twice daily dose). Adrenal pheochromocytomas were increased relative to controls in males receiving 3 mg/kg/day and above, and in females receiving 10 mg/kg/day and above (at least 10 and 18 times respectively human AUC exposure after a 1 mg twice daily dose).

Anagrelide hydrochloride at oral doses up to 240 mg/kg/day (233 times the recommended human dose of 10 mg/day based on body surface area) had no effect on fertility and reproductive function of male rats. However, in fertility studies in female rats, oral doses of 30 mg/kg/day (29 times the recommended maximum human dose based on body surface area) or higher resulted in increased pre- and post-implantation loss and a decrease in the number of live embryos.

In the 2-year rat study, a significant increase in non-neoplastic lesions was observed in anagrelide treated males and females in the adrenal (medullary hyperplasia), heart (myocardial hypertrophy and chamber distension), kidney (hydronephrosis, tubular dilation and urothelial hyperplasia), and bone (femur enostosis). Vascular effects were observed in tissues of the pancreas (arteritis/periarteritis, intimal proliferation, and medial hypertrophy), kidney (arteritis/periarteritis, intimal proliferation, and medial hypertrophy), sciatic nerve (vascular mineralization), and testes (tubular atrophy and vascular infarct) in anagrelide-treated males.