Usage
- Pitofenone hydrochloride is prescribed for the symptomatic relief of pain associated with smooth muscle spasms in the gastrointestinal tract, biliary tract, urinary tract, and uterus. Conditions it is used for include renal colic, biliary colic, intestinal colic, and dysmenorrhea.
- Pharmacological classification: Antispasmodic (spasmolytic).
- Mechanism of action: Pitofenone exerts a direct papaverine-like myotropic effect on smooth muscle, reducing spasms and relaxing the musculature of the affected organs.
Alternate Names
- No widely recognized alternate names.
- Brand names: Often found in combination medications marketed under various brand names such as Spasmalgon, Spasmobloc, and others depending on the region.
How It Works
- Pharmacodynamics: Pitofenone acts directly on the smooth muscle, inhibiting contractions and causing relaxation. This leads to a reduction in pain caused by spasms.
- Pharmacokinetics: Limited information available on the specific pharmacokinetics of Pitofenone alone. Primarily absorbed orally and metabolized within the liver with subsequent renal and hepatic elimination
- Mode of action: Acts directly on the smooth muscle cells by inhibiting calcium channels, resulting in decreased intracellular calcium levels. This decrease in calcium prevents muscle contraction and reduces spasms. It possesses papaverine-like myotropic effects.
- Receptor binding, enzyme inhibition, or neurotransmitter modulation: Pitofenone’s primary mechanism is through direct action on smooth muscle cells rather than through receptor binding, enzyme inhibition, or neurotransmitter modulation.
- Elimination pathways: Primarily metabolized in the liver. Elimination pathways not fully defined but likely include renal and hepatic excretion of metabolites.
Dosage
Standard Dosage
Adults:
- Oral administration: 1-2 tablets (containing Pitofenone hydrochloride 5 mg) 2-3 times daily, typically after meals. Maximum daily dose is usually 6 tablets. Duration of treatment should not exceed 3 days.
Children:
- 9-12 years: ½ tablet 2-3 times daily. Maximum daily dose is 2 tablets.
- 12-15 years: 1 tablet 2-3 times daily. Maximum daily dose is 3 tablets.
Special Cases:
- Elderly Patients: Dose reduction may be required due to age-related changes in hepatic and renal function. Start with a lower dose and adjust based on individual tolerance.
- Patients with Renal Impairment: Dose adjustments are likely necessary due to altered drug clearance. Monitor renal function closely.
- Patients with Hepatic Dysfunction: Caution advised, as reduced liver function might affect drug metabolism. Start with a lower dose and titrate carefully according to patient tolerance and hepatic function parameters.
- Patients with Comorbid Conditions: Individualized assessment and dose adjustments may be required based on specific conditions.
Clinical Use Cases
- Intubation, Surgical Procedures, Mechanical Ventilation, Intensive Care Unit (ICU) Use, Emergency Situations: Pitofenone is generally not indicated for these scenarios. Its use is primarily limited to pain management associated with smooth muscle spasms.
Dosage Adjustments:
- Dose reductions are needed in patients with hepatic or renal impairment. Close monitoring is recommended.
- In elderly patients, initiate treatment with a lower dose and adjust gradually based on clinical response and patient tolerance.
Side Effects
Common Side Effects
- Dizziness
- Headache
- Dry mouth
- Skin rash
- Itching
Rare but Serious Side Effects
- Allergic reactions (rash, itching, angioedema, bronchospasm, anaphylactic shock)
- Blood dyscrasias (agranulocytosis, thrombocytopenia, leukopenia)
- Renal dysfunction
- Hepatic dysfunction
Long-Term Effects: Not typically used for long-term treatment, therefore, long-term effects data is limited.
Contraindications
- Hypersensitivity to Pitofenone or any component of the combined medication.
- Severe hepatic or renal impairment.
- Pregnancy (especially the third trimester).
- Breastfeeding.
- Children with a body weight below 16 kg and generally under 18 years of age due to limited safety and efficacy data.
- History of drug-induced blood disorders.
- Porphyria.
Drug Interactions
- Other antispasmodics: May have additive effects.
- Medications affecting liver enzymes: Potential for altered drug metabolism.
- Alcohol: Should be avoided as it can exacerbate side effects.
- Anticoagulants: Use with caution as Metamizole, often combined with pitofenone, may have some anticoagulant properties.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: Contraindicated. It is not administered during pregnancy due to potential risks to the fetus.
- Fetal risks: May cause adverse effects in the newborn, especially in the third trimester.
- Drug excretion in breast milk: Pitofenone passes into breast milk, therefore breastfeeding is contraindicated.
- Safer alternatives during pregnancy include other agents like hyoscine butylbromide depending on the specific indication.
Drug Profile Summary
- Mechanism of Action: Direct smooth muscle relaxant.
- Side Effects: Dizziness, headache, dry mouth, skin rash, itching, allergic reactions, blood dyscrasias.
- Contraindications: Hypersensitivity, severe liver or kidney disease, pregnancy, breastfeeding.
- Drug Interactions: Other antispasmodics, medications affecting liver enzymes, alcohol.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: Adults: 1-2 tablets 2-3 times daily; Children: age dependent reduction in dosage (see Dosage section for details); Elderly: Dose adjustments based on organ function.
- Monitoring Parameters: Liver and renal function tests, blood cell counts in case of long-term or high-dose use, symptoms for hypersensitivity.
Popular Combinations
- Often combined with metamizole sodium and fenpiverinium bromide (e.g., Spasmalgon) to provide enhanced analgesic and antispasmodic effects.
Precautions
- General Precautions: Screen for allergies, hepatic or renal dysfunction before administration.
- Specific Populations: Contraindicated in pregnant and breastfeeding women. Use with caution in children and the elderly.
- Lifestyle Considerations: Avoid alcohol. May impair driving abilities due to dizziness.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Pitofenone?
A: The recommended adult dosage is 1-2 tablets (5mg Pitofenone hydrochloride per tablet) 2-3 times daily, usually after meals, for a maximum of 3 days. Pediatric dosages are lower and depend on the age group (see Dosage section).
Q2: What are the main uses of Pitofenone?
A: Pitofenone is primarily used to relieve pain caused by smooth muscle spasms in the gastrointestinal, biliary, urinary tracts, and uterus.
Q3: What are the common side effects of Pitofenone?
A: Common side effects include dizziness, headache, dry mouth, skin rash, and itching.
Q4: Is Pitofenone safe to use during pregnancy or breastfeeding?
A: No. Pitofenone is contraindicated during pregnancy and breastfeeding.
Q5: What are the serious side effects to watch out for when prescribing Pitofenone?
A: Serious side effects include allergic reactions (ranging from skin rashes to anaphylaxis) and blood dyscrasias (agranulocytosis, thrombocytopenia, leukopenia). Monitor patients for these reactions and advise them to seek immediate medical attention if they occur.
Q6: Are there any drug interactions I should be aware of when prescribing Pitofenone?
A: Yes. Concomitant use of Pitofenone with other antispasmodics may have additive effects. It might also interact with medications that affect liver enzymes, potentially altering drug metabolism. Alcohol should be avoided. Inform patients about these potential interactions.
Q7: Can Pitofenone be used in patients with liver or kidney disease?
A: Pitofenone should be used with caution in patients with hepatic or renal impairment, and dose adjustments may be necessary. It is contraindicated in cases of severe liver or kidney dysfunction. Close monitoring is required in these patient populations.
Q8: How does Pitofenone work to relieve muscle spasms?
A: Pitofenone acts directly on the smooth muscle cells, inhibiting calcium channels and reducing intracellular calcium levels. This leads to a decrease in muscle contractions and subsequent relief of spasms.
Q9. How long is a typical course of treatment with Pitofenone?
A: A typical course of treatment with pitofenone should not exceed 3 days. If symptoms persist beyond this period, re-evaluate the diagnosis and consider alternative treatment strategies.
