Pizo-A1.5 mg

Pizo-A is indicated for the prophylaxis (prevention) of recurrent vascular headache of the migraine type, including classical migraine, common migraine, and cluster headache.

• Established use: Migraine prophylaxis in adults and children who experience frequent or severe migraine attacks (guideline-supported, first-line/second-line prophylactic option in several national migraine guidelines).
• Established use: Prophylaxis of cluster headache.

Pizo-A is not effective for treating an acute migraine attack that has already started, and it is not an analgesic. It is intended only to reduce the frequency and severity of future attacks, and its full preventive benefit typically takes several weeks to become apparent.

Each tablet contains Pizotifen (as pizotifen malate/hydrogen maleate) as the active ingredient. In Bangladesh, Pizotifen is commonly available as oral tablets in strengths of 0.5 mg and 1.5 mg, along with the usual pharmaceutical excipients (including lactose in many formulations).

Pizo-A is a tricyclic benzocycloheptathiophene compound with combined serotonin (5-HT2) receptor antagonist and antihistamine (H1 receptor antagonist) activity, along with mild anticholinergic and anti-bradykinin (anti-kinin) properties. It is used chiefly as a prophylactic (preventive) treatment for migraine and cluster headache, taken on a regular daily basis rather than during an attack.

Because of its antihistaminic and central sedative effects, Pizo-A is also associated with drowsiness and increased appetite, which are expected pharmacological effects rather than idiosyncratic reactions.

Pizo-A belongs to the therapeutic class of antihistamine preparations / antimigraine agents, specifically a serotonin (5-HT2) and histamine (H1) receptor antagonist used for migraine prophylaxis.

Mechanism of Action

Pizotifen is a tricyclic compound that acts primarily as a competitive antagonist at serotonin (5-HT2) receptors and histamine (H1) receptors. It also has weak anticholinergic and anti-bradykinin (anti-kinin) activity.

In migraine prophylaxis, Pizotifen is thought to work by inhibiting the actions of serotonin and histamine on cranial blood vessel permeability and tone, reducing neurogenic inflammation, and raising the threshold for migraine attacks. It has no established analgesic or vasoconstrictor action and therefore does not relieve an attack once it has begun.

Pharmacokinetics

Pizotifen is well absorbed after oral administration, undergoes hepatic metabolism, and is eliminated mainly via the kidneys as metabolites, with a long elimination half-life that supports once-daily or divided dosing.

Pizo-A tablets should be taken by mouth, with or without food. Because drowsiness is a common effect, the once-daily dose is usually best taken at bedtime; when divided doses are used, the largest portion is generally given in the evening. Tablets should be swallowed whole with water; do not crush or chew unless advised otherwise by a physician or pharmacist. Take Pizo-A at the same time(s) each day for consistent preventive effect, and do not skip doses.

Pizo-A has the following clinically significant drug interactions:

• Monoamine oxidase inhibitors (MAOIs): Concurrent use with MAOIs is generally contraindicated/not recommended due to the risk of additive and unpredictable effects; MAOIs should be stopped for the recommended washout period before starting Pizo-A.
• CNS depressants (alcohol, sedatives, hypnotics, benzodiazepines, other sedating antihistamines, tricyclic antidepressants): Pizo-A enhances the sedative effects of these agents, increasing the risk of excessive drowsiness and impaired alertness. Combination should be avoided or used with caution.
• Adrenergic neurone blockers (e.g. guanethidine-type antihypertensives): Pizo-A may antagonize their blood-pressure-lowering effect, potentially reducing antihypertensive control.
• Other anticholinergic drugs: Additive anticholinergic effects (dry mouth, urinary retention, constipation, blurred vision) may occur when combined with other drugs having antimuscarinic activity.

Always inform your physician or pharmacist about all medicines, supplements, and alcohol use before starting Pizo-A.

Side effects of Pizo-A are largely related to its antihistaminic and anticholinergic activity.

Very Common

• Increased appetite and weight gain
• Drowsiness/sedation, especially at the start of treatment

Common

• Dry mouth
• Dizziness
• Nausea
• Fatigue/lethargy

Uncommon/Rare

• Urinary retention or difficulty urinating
• Blurred vision
• Muscle pain, nervousness, or sleep disturbance
• Hepatic injury (transaminase elevation to rare hepatitis) — reported rarely
• Hypersensitivity reactions (rash, angioedema) — rare

Patients should seek medical advice if side effects are severe, persistent, or if signs of liver problems (yellowing of skin/eyes, dark urine) or allergic reaction occur.

Pregnancy: Clinical data on the use of Pizo-A in pregnant women are very limited. Pizo-A should be used during pregnancy only if clearly needed and if the potential benefit to the mother justifies the potential risk to the fetus. Consult a physician before use if pregnant or planning pregnancy.

Lactation: Pizo-A passes into breast milk in small amounts; because safety in nursing infants has not been established, use during breastfeeding is generally not recommended. A physician should be consulted to weigh the benefits of therapy against potential risk to the breastfeeding infant.

• Not for acute attacks: Pizo-A is a preventive therapy only; it does not relieve a migraine attack once it has started, and benefit may take several weeks to become apparent.
• Angle-closure glaucoma / urinary retention: Due to anticholinergic activity, Pizo-A should be used with caution in patients with (or predisposed to) angle-closure glaucoma or urinary retention (e.g. prostatic hypertrophy), as it may worsen these conditions.
• History of epilepsy/seizures: Use with caution in patients with a history of epilepsy or convulsive disorders; monitor clinically.
• Hepatic impairment: Rare cases of hepatic injury (including hepatitis) have been reported; use with caution and monitor liver function in patients with hepatic disease or unexplained symptoms suggestive of liver injury.
• Renal impairment: Use with caution; dosage adjustment may be needed.
• Sedation: Pizo-A commonly causes drowsiness, which may impair the ability to drive or operate machinery, especially at the start of treatment or with dose increases. Alcohol enhances this sedative effect and should be avoided or minimized.
• Do not stop abruptly: After prolonged use, Pizo-A should not be stopped suddenly, as withdrawal symptoms (depression, tremor, nausea, anxiety, malaise, dizziness, sleep disturbance, weight loss) have been reported. Discontinuation should be done gradually under medical supervision.
• Elderly patients: May be more sensitive to the sedative and anticholinergic effects; use cautiously.

Overdose with Pizo-A may cause marked drowsiness, disorientation, agitation, rapid heartbeat, and, in severe cases, seizures or low blood pressure, particularly in children.

If an overdose of Pizo-A is suspected, seek immediate medical attention or contact emergency services/a poison control center right away — do not wait for symptoms to appear. Take the medicine container/packaging to the hospital. Treatment is supportive and should be carried out under medical supervision; do not attempt specific home treatment beyond general first-aid measures and prompt medical care.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Pediatric Use

Pizo-A may be used for migraine prophylaxis in children aged 2 years and above, at lower doses than adults and under medical supervision. Safety and efficacy in children under 2 years of age have not been established.

Elderly

No specific dose adjustment is generally required in the elderly, but they may be more sensitive to sedative and anticholinergic effects, so caution is advised.

Hepatic Impairment

Use with caution; dosage adjustment may be necessary, and liver function should be monitored (see Precautions and Warnings).

Renal Impairment

Use with caution; dosage adjustment may be necessary.

Pregnancy and Breastfeeding

See Pregnancy and Lactation section — use only if clearly needed, under medical advice.

An initial trial of Pizo-A for approximately 6–8 weeks at an adequate dose is usually recommended to assess whether it is effective in reducing migraine frequency/severity. If there is no meaningful benefit after this period, a physician may consider discontinuing or switching therapy. If effective, treatment is often continued for several months, with periodic medical review (e.g. every 3–6 months) to reassess the ongoing need for prophylaxis; when stopping, the dose should be tapered gradually rather than stopped abruptly.

Antihistamine (H1 receptor antagonist); Serotonin (5-HT2) receptor antagonist; Antimigraine prophylactic agent

Pizotifen acts as a competitive antagonist at serotonin (5-HT2) and histamine (H1) receptors, with additional weak anticholinergic and anti-bradykinin (anti-kinin) activity. By blocking these mediators' effects on cranial vessel permeability and neurogenic inflammation, Pizotifen raises the threshold for migraine attacks, reducing their frequency and severity when taken regularly as a preventive treatment.

Pizo-A may be used in children aged 2 years and above for the prophylaxis of migraine, typically at doses up to about 1–1.5 mg daily in divided doses, under close medical supervision. Sedation and increased appetite/weight gain should be monitored, as children may be particularly sensitive to these effects.

Safety and efficacy of Pizo-A in children under 2 years of age have not been established, and it should not be used in this age group.