Pizotifen

Although anticholinergic effects (constipation, xerostomia, blurred vision, urinary retention) are limited, use with caution in patients with decreased gastrointestinal motility, myasthenia gravis, paralytic ileus, urinary retention, BPH, xerostomia, narrow-angle glaucoma, or other vision problems. Ophthalmic screening is recommended.

May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving). Gradual titration of dose may help minimize sedative effects (eg, drowsiness).

Hepatotoxic effects may occur with prolonged used; periodic evaluation of liver function is recommended during therapy. Discontinue use for signs/symptoms of hepatic dysfunction and do not resume therapy until etiology of hepatic dysfunction is identified.

Use has been associated with increased intraocular pressure, diplopia, and pupil dilation; limited number of patients experienced lens opacities but effect was not considered drug-related. Instruct patients to report visual disturbances during therapy.

Increased appetite and weight gain are common adverse effects; patients may experience rapid weight loss upon discontinuation. Use with caution in obese or other patients who may be vulnerable to these effects. Disease-related concerns:

Use with caution in patients with cardiovascular disease.

Use with caution in patients with diabetes mellitus.

Use with caution in patients with epilepsy; seizures have been reported very rarely with use.

Use with caution in patients with hepatic impairment. Dose adjustment may be necessary.

Use with caution in patients with renal impairment. Dose adjustment may be necessary. Concurrent drug therapy issues:

Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information. Dosage forms specific issues:

May contain lactose; avoid use in patients with galactose or fructose intolerance, lactase deficiency, sucrose-isomaltase insufficiency, or glucose-galactose malabsorption. Other warnings/precautions:

Avoid abrupt discontinuation which may cause acute withdrawal reactions (eg, depression, tremor, nausea, malaise, sleep disorder, dizziness, anxiety, loss of consciousness, anorexia and rapid weight loss); taper dosage over 2 weeks prior to discontinuation.

Not for use in acute treatment of migraine attacks or of tension headaches. Not considered first-line agent for migraine prophylaxis but may be considered when other therapies have failed (Pringsheim, 2012).

Therapeutic response may require several weeks of therapy. Some patients may experience a decrease in therapeutic response over time.

May develop in some patients; effect may be overcome by dose increases (not to exceed maximum dosage). Consider drug-free period after several months of treatment.