Usage
Pholcodine + Promethazine is prescribed for the relief of dry, non-productive coughs, often associated with the common cold or allergies. It also provides relief from allergy symptoms like runny nose, sneezing, and watery eyes. Additionally, it may be used to manage nausea and vomiting, motion sickness, and as a preoperative sedative.
Its pharmacological classifications include:
- Antitussive: Pholcodine suppresses the cough reflex by acting directly on the cough center in the brain.
- Antihistamine (first-generation): Promethazine blocks the action of histamine, reducing allergic symptoms. It also has sedative, antiemetic, and anticholinergic properties.
Alternate Names
There are no widely recognized alternate generic names. Brand names vary by region and may include combinations with other drugs. Some examples are “Codo-Q Junior” and “Tixylix.”
How It Works
Pharmacodynamics: Pholcodine acts centrally on the cough center in the medulla to suppress the cough reflex. Promethazine is an H1 receptor antagonist, blocking the effects of histamine. It also possesses anticholinergic, sedative, and antiemetic properties.
Pharmacokinetics: Both drugs are absorbed orally. Pholcodine is metabolized in the liver and excreted renally. Promethazine is also metabolized in the liver, primarily by CYP450 enzymes, with both renal and biliary excretion.
Mode of Action: Pholcodine is an opioid agonist that binds to opioid receptors in the cough center, decreasing its sensitivity and suppressing the cough reflex. Promethazine competitively antagonizes H1 receptors, preventing histamine from binding and exerting its effects.
Elimination Pathways: Pholcodine is primarily excreted renally. Promethazine undergoes hepatic metabolism followed by both renal and biliary excretion.
Dosage
Standard Dosage
Adults: The typical adult dose is 5-10 mg of Pholcodine and 6.25-25mg of Promethazine, which can be administered three or four times daily as needed. Alternatively, 10-15 mg of Pholcodine with 25-50mg of Promethazine can be administered every 8-10 hours.
Children: Use with caution in children. Dosing must be determined by a doctor based on weight and age. The combination is generally contraindicated in children under 6 years old.
Special Cases:
- Elderly Patients: Reduced dosage is recommended due to age-related decline in hepatic and renal function.
- Patients with Renal Impairment: Caution is advised. Dosage adjustment may be necessary depending on the severity of impairment.
- Patients with Hepatic Dysfunction: Caution is advised. Dosage adjustment may be necessary.
- Patients with Comorbid Conditions: Use with caution in patients with respiratory conditions like asthma or COPD, cardiovascular disease, glaucoma, and prostatic hypertrophy.
Clinical Use Cases Dosages in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, and emergency situations should be guided by individual patient needs and clinical judgment under the supervision of an anesthesiologist or critical care specialist. The sedative and antiemetic properties may be useful, but potential respiratory depression needs careful consideration.
Dosage Adjustments Adjust dosages based on patient response, renal/hepatic function, and other patient-specific factors.
Side Effects
Common Side Effects: Drowsiness, dizziness, dry mouth, constipation, blurred vision, nausea, and vomiting.
Rare but Serious Side Effects: Seizures, tremor, akathisia, respiratory depression (especially in children), severe allergic reactions (including anaphylaxis), and extrapyramidal symptoms.
Long-Term Effects: Chronic complications are rare but potential long-term effects with prolonged use include tardive dyskinesia and dependence on pholcodine.
Contraindications
- Hypersensitivity to either drug.
- Respiratory depression or failure.
- Acute asthma attack.
- Chronic bronchitis, COPD, bronchiolitis, or bronchiectasis.
- Liver disease.
- Concomitant use of MAOIs.
- Children under 6 years of age.
Drug Interactions
- CNS depressants (e.g., alcohol, opioids, sedatives): Increased sedation and respiratory depression.
- Anticholinergic drugs (e.g., atropine): Enhanced anticholinergic effects.
- MAO inhibitors: Hypertensive crisis.
- CYP450 inhibitors/inducers: May alter the metabolism of promethazine.
Pregnancy and Breastfeeding
Use with caution during pregnancy and breastfeeding. Safety has not been established, and potential fetal risks exist. Consult with a specialist to weigh the benefits against potential risks. If possible, alternative safer options may be considered.
Drug Profile Summary
- Mechanism of Action: Pholcodine: Opioid cough suppressant. Promethazine: H1 receptor antagonist with anticholinergic, sedative, and antiemetic properties.
- Side Effects: Drowsiness, dizziness, dry mouth, constipation, blurred vision, nausea, vomiting. Rarely: Seizures, tremor, respiratory depression, allergic reactions.
- Contraindications: Hypersensitivity, respiratory compromise, acute asthma, severe liver disease, MAOI use.
- Drug Interactions: CNS depressants, anticholinergics, MAOIs.
- Pregnancy & Breastfeeding: Use with caution. Safety not established.
- Dosage: Adults: 5-10 mg pholcodine and 6.25-25 mg promethazine 3-4 times/day OR 10-15 mg pholcodine with 25-50mg promethazine every 8-10 hours. Children: Consult a specialist; generally not recommended under 6.
- Monitoring Parameters: Respiratory rate, mental status, allergic reactions.
Popular Combinations
Pholcodine and promethazine are often combined with other medications, like decongestants (e.g., phenylephrine) or analgesics (e.g., paracetamol) to provide broader symptomatic relief for cold and flu.
Precautions
- Assess for allergies, respiratory conditions, liver/kidney function, and other relevant medical history before prescribing.
- Monitor patients closely, particularly children and the elderly, for adverse effects.
- Caution patients about potential drowsiness and impaired coordination, advising against driving or operating heavy machinery.
- Avoid alcohol during treatment.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Pholcodine + Promethazine?
A: The adult dosage can vary, ranging from 5-10 mg pholcodine and 6.25-25 mg promethazine three to four times a day, or 10-15mg of Pholcodine with 25-50mg of Promethazine every 8-10 hours. Pediatric doses must be determined by a physician based on weight and age.
Q2: What are the most common side effects?
A: Drowsiness, dizziness, dry mouth, constipation, and blurred vision are the most common side effects.
Q3: Can it be used in children under 6?
A: It is generally contraindicated for children under 6 years of age due to the risk of respiratory depression.
Q4: What are the contraindications?
A: Contraindications include hypersensitivity, respiratory depression, acute asthma attack, severe liver disease, and concomitant MAOI use.
Q5: What should I monitor in patients taking this medication?
A: Monitor respiratory rate, mental status, and any signs of allergic reactions.
Q6: Can this medication be used during pregnancy?
A: Use with caution during pregnancy. Safety has not been fully established, and potential fetal risks exist. Consult a specialist to evaluate the benefits against risks.
Q7: What are the potential drug interactions?
A: The medication can interact with CNS depressants (like alcohol and opioids), anticholinergics, and MAOIs.
Q8: Can this medicine be used with other cough and cold medications?
A: Avoid concurrent use with other cough and cold medications, especially those containing antihistamines or CNS depressants, due to increased risk of side effects.
Q9: What are the signs of an overdose?
A: Signs of overdose include severe drowsiness, confusion, respiratory depression, seizures, and coma.
Q10: What is the treatment for an overdose?
A: Supportive care and symptomatic treatment. In case of opioid overdose from Pholcodine, naloxone may be administered.
