Syndol SL

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Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Syndol SL

Quick Facts

Property Description
Active ingredient Ketorolac tromethamine
Form Sublingual tablet (SL)
Pharmacological class Non-Steroidal Anti-Inflammatory Drug (NSAID)
Common use Short-term management of moderate to severe pain
Origin Synthetic compound (pyrrolo-pyrrole derivative)

What is Syndol SL?

What Type of Medicine is Syndol SL?

Syndol SL is a prescription-only medication classified as a Non-Steroidal Anti-Inflammatory Drug (NSAID), with its primary function being a potent analgesic (pain-reliever). The active compound, Ketorolac tromethamine, is clinically recognized for providing effective, short-term relief in scenarios involving acute, intense discomfort. This classification confirms the drug's systemic action and its general purpose: to provide effective relief from moderate to severe pain. The medicine’s strength places it among the most potent non-opioid options available for pain management.

Composition and Origin: The Role of Ketorolac Tromethamine

The foundational element of Syndol SL is the single, synthetic compound, Ketorolac tromethamine, which belongs to the pyrrolo-pyrrole chemical family. As a non-selective NSAID, this compound’s mechanism involves acting as a cyclooxygenase (COX) inhibitor, meaning it interferes with the conversion of arachidonic acid into prostaglandins. These prostaglandins are crucial chemical messengers in the body that initiate and sustain inflammation, pain, and fever. By blocking this chemical pathway, the medicine delivers reliable and focused anti-pain action throughout the body.

The Sublingual (SL) Tablet Form

Syndol SL is specifically formulated as a sublingual tablet, which means the solid dosage form is designed to dissolve rapidly when placed under the tongue (the sublingual route of administration). The 'SL' designation refers precisely to this administration route. This method is a distinctive feature of Syndol SL, as it is intended to facilitate a rapid onset of systemic analgesic effects, an attribute observed in clinical pharmacokinetics. This specialized sublingual delivery is often utilized in contexts where prompt relief from acute discomfort is medically necessary.

Regulatory References

  1. NIH, Ketorolac Sublingual Tablet

What side effects are possible with Syndol SL?

Possible Side Effects and Safety Information

Syndol SL contains paracetamol, codeine, and doxylamine, and its safety profile reflects the risks associated with these active ingredients.

Adverse Reactions

The most frequently reported side effects are constipation and drowsiness (somnolence). Less frequent reactions involve the nervous system (dizziness, headache), gastrointestinal tract (nausea, vomiting, dry mouth), and cardiovascular system (orthostatic hypotension, palpitations).

Serious and Clinically Significant Adverse Reactions

Serious adverse reactions documented in regulatory sources include respiratory depression, anaphylactic shock, and hepatic failure (liver damage), the latter primarily associated with paracetamol overdose. Prolonged and regular use of codeine carries a risk of developing addiction and physical dependence, leading to withdrawal symptoms upon cessation. Very rare cases of serious skin reactions and thrombocytopenia (low platelet count) have also been reported.

Safety Restrictions and Monitoring

Syndol SL is contraindicated in children under 12 years of age, in adolescents under 18 following surgery for obstructive sleep apnoea, during the last trimester of pregnancy, and while breast-feeding. It is also restricted in individuals with severe breathing problems, recent head injury, or those taking Monoamine Oxidase Inhibitors (MAOIs).

Due to the risk of drowsiness, patients are cautioned against driving or operating heavy machinery until they understand the full effects of the medicine. Concomitant use with alcohol or other CNS depressants greatly increases the risk of profound sedation, respiratory depression, and coma. Patients are advised not to take any other medicines containing paracetamol or codeine while using Syndol SL.

Overdose and Emergency Response

Overdose and When to Seek Help

The primary risk of overdose with this type of pain medicine relates to severe depression of the Central Nervous System (CNS) and the respiratory system, which can be life-threatening. Official sources describe documented overdose presentations as symptoms such as slowed, shallow, or difficult breathing, extreme sleepiness, unusual dizziness or lightheadedness, or unresponsiveness (the inability to wake up or respond).

Overdose risk is significantly increased by factors such as taking higher doses than prescribed, or using the medicine in combination with other CNS depressants, including benzodiazepines or alcohol. The combination of these substances has been officially associated with serious outcomes, including death.

Required Emergency Actions

Immediate medical attention is required if you or a caregiver observe any signs of respiratory distress or profound sedation. You must seek emergency medical help or call 911 immediately if these symptoms occur.

Physicians are required to discuss the availability of opioid overdose reversal agents, such as naloxone, with patients prescribed these medications. Naloxone is a medication that can temporarily reverse the effects of an opioid overdose on breathing and should be accessible and administered when an overdose is suspected, even before emergency medical services arrive. After administration, emergency help must still be sought immediately.

Therapeutic Uses of Syndol SL

What Syndol SL Treats: Main Uses and Benefits

The primary therapeutic use of Syndol SL (referring to the four-component combination) is for short-term, symptomatic relief in contexts where symptoms that interfere with daily functioning are present. It is used in situations involving certain distressing symptoms, particularly those associated with a tension state origin.

The medication is commonly used across conditions characterized by episodic or fluctuating manifestations, and may assist in addressing symptoms related to physical discomfort such as tension headaches, toothache, muscular or rheumatic aches, and menstrual discomfort (dysmenorrhoea). It is applied in clinical settings that involve acute or unstable symptom patterns.

“The product is relevant in contexts marked by increased discomfort or tension, applied in addressing symptoms related to heightened neurological or muscular activity.”

This supportive symptomatic approach helps manage the intensity of these symptoms, providing support that helps ease the overall symptom burden during phases when symptoms become more noticeable. It assists with maintaining functional stability and supports general well-being during symptomatic phases.


Quick Fact: Relief for Tension Pain The formulation is commonly applied to symptom clusters that involve a combination of both pain and associated muscle tension, making it relevant for managing the discomfort of tension-type headaches.


Regulatory References

  1. Irish Health Products Regulatory Authority (HPRA) product information

Eligibility and Restrictions for Use

The eligibility for using Syndol SL (Ketorolac tromethamine) is strictly defined by official regulatory documents, limiting use to adult patients aged 17 years and older. Safety and effectiveness have not been established in pediatric populations.

The medicine is CONTRAINDICATED and must not be used by several specific populations:

  • Patients with a history of active peptic ulcer disease, gastrointestinal bleeding, or perforation.
  • Individuals diagnosed with advanced renal impairment, severe hepatic failure, or severe heart failure.
  • Those with known hypersensitivity to ketorolac tromethamine, aspirin, or any other NSAIDs.
  • Women in the third trimester of pregnancy, during labor and delivery, or who are breastfeeding.
  • Patients currently receiving aspirin or other NSAIDs, or those in the setting of Coronary Artery Bypass Graft (CABG) surgery.

Use is restricted and requires specific precautions for older adults (65 years and over) and patients weighing less than 50 kg, who require dosage adjustments due to increased risk of adverse reactions. The total duration of use for all eligible adults must not exceed five days.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory information requires strict adherence to specific constraints regarding the concurrent use of Syndol SL with other medications and substances.

Medicines Not to Be Combined

Do not take this medicine with Monoamine Oxidase Inhibitors (MAOIs), or within 14 days of discontinuing treatment with them, due to the potential risk of serotonin syndrome from the doxylamine component. Furthermore, this medicine must not be taken concurrently with any other product containing paracetamol or codeine to prevent accidental overdose and severe toxicity, particularly liver damage.

Medicines Requiring Caution and Monitoring

Concomitant use of the codeine component with sedative medicines such as benzodiazepines, or with alcohol, increases the risk of profound sedation, respiratory depression, coma, and death; this combination should be avoided unless strictly necessary and monitored closely by a healthcare professional. For patients taking warfarin or other oral anticoagulants, the paracetamol component may increase the anticoagulant effect, requiring close monitoring of the International Normalized Ratio (INR) to manage the risk of bleeding. Caution is also advised when co-administering with enzyme-inducing antiepileptic medications, which may increase the toxicity potential of the paracetamol component.

Mechanism of Action

️ How Syndol SL Works

Syndol SL (Ketorolac tromethamine) functions as a non-selective inhibitor within the eicosanoid synthesis pathway, exerting its effect through dual-action modulation of nociceptive signaling pathways.


️ Inhibition of COX Enzymes: The Molecular Blockade

The primary molecular target is the Cyclooxygenase (COX) enzymes. Syndol SL works by non-selectively and competitively inhibiting both the constitutive COX-1 and inducible COX-2 isoforms. This inhibition prevents these enzymes from converting arachidonic acid into prostaglandins and thromboxanes. Modifying this early molecular step influences systemic physiological outcomes by suppressing the biosynthesis of chemical mediators.


Modulation of Nociceptive Signaling (Central and Peripheral)

The reduction in prostaglandins translates into modulation of nervous system function. By suppressing local prostaglandin production, the drug reduces the sensitization of peripheral nerve endings. Simultaneously, the drug engages mechanisms that influence pain signaling centrally, causing attenuation of nociceptive signal amplification within the spinal cord. This dual action on peripheral and central pathways results in altered signal transmission through nociceptive pathways.

Dosage and Administration Information

How to Use Syndol SL: Official Administration Guidelines

This section outlines the established instructions for the administration and dosing of Syndol SL (Paracetamol, Codeine, and Doxylamine combination). Adherence to these guidelines is required for correct use.

Route and Method of Administration

Syndol SL tablets are for oral use only. The tablets must be swallowed whole with water and should not be chewed.

Dosing Schedule and Age-Specific Use

The dosage for Syndol SL is strictly defined by age group and frequency, ensuring the maximum daily limits are not exceeded. Use of this medicine is not permitted for children under 12 years of age.

Age Group Dose Amount Dosing Frequency (Minimum Interval) Maximum Dose in 24 Hours
Adults and Children 16 years and over 1 or 2 tablets Every 4 to 6 hours 8 tablets
Children 12 to 15 years 1 tablet Every 6 hours 4 tablets

Maximum Duration of Use

This medicine must be used for a maximum of three consecutive days. If pain relief is still required after three days, a doctor or pharmacist must be consulted before continuing use. This restriction is a mandatory component of the administration protocol.

Recent Clinical Evidence

Recent Clinical Evidence: Syndol SL

Syndol SL is a fixed-dose combination analgesic containing paracetamol, the opioid codeine phosphate, and the sedative antihistamine doxylamine succinate.


Efficacy and Combination Studies

Clinical research on combination products containing paracetamol, codeine, and doxylamine has primarily examined the benefits of using multiple components for pain relief, particularly in conditions like headache, dental pain, and post-operative discomfort. One double-blind, crossover trial compared a combination of paracetamol, codeine phosphate, doxylamine succinate, and caffeine (a formulation similar to Syndol SL) against a placebo for the relief of acute migraine attacks. The results suggested the combination was associated with a greater rate of complete or partial pain relief compared to placebo.


Role of Doxylamine and Tolerability

The inclusion of doxylamine succinate, an H1 antagonist with sedative effects, is intended to provide a mild sedative effect, which may be helpful in managing pain associated with tension or muscle strain. However, doxylamine's primary effect is to induce drowsiness, which is a frequently reported adverse event in combination formulations containing it.

Safety and adverse events are well-documented across trials involving codeine-containing analgesics. The most commonly reported side effects across combination studies include nausea, headache, and fatigue. The combination of paracetamol and codeine is known to carry risks associated with respiratory depression and dependency, particularly with prolonged use or overdose, necessitating strict adherence to prescribing information.


Research Gaps

Direct, modern clinical trials specifically comparing the efficacy and safety of the Syndol SL fixed-dose formulation against its individual components or other leading analgesics remain limited. Data collection is ongoing to determine the drug's role in standard care for various pain conditions and to further define the optimal dosing for specific patient populations, such as those with co-existing liver or kidney conditions.

How should Syndol SL be stored and disposed of?

How to Store and Dispose of Syndol SL?

Syndol SL (Ketorolac Tromethamine sublingual tablets) must be stored strictly according to official regulatory specifications to maintain the drug's integrity.


Official Storage Requirements

Condition Requirement
Temperature Store at controlled room temperature, specifically between 20 C and 25 C (68 F and 77 F).
Handling Do not refrigerate or freeze. Keep away from high heat.
Protection The container must be tight and light-resistant to protect the medicine from moisture and direct light.
Child Safety Mandatory instruction: Keep this medication out of the sight and reach of children.

Disposal Instructions

Official guidelines require the disposal of outdated or unused medicine. It should not be saved for future use. The recommended method for proper disposal is utilizing an authorized drug take-back program or following the specific instructions of local waste management authorities for unused pharmaceuticals.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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