Lyrica Oral Solution

Description

Lyrica oral solution 20 mg/mL is a liquid formulation of pregabalin, a gamma‑aminobutyric acid (GABA) analogue used as an analgesic and anticonvulsant in various neurologic and pain conditions in adults and selected paediatric populations. It is authorized in multiple regions, including Europe and the United Kingdom, and contains pregabalin as the active substance at a concentration of 20 mg per millilitre, corresponding to the same active ingredient as Lyrica capsules but in an oral solution suitable for patients with swallowing difficulties or requiring flexible dosing.

Qualitative and Quantitative Composition

Each millilitre of Lyrica oral solution contains 20 mg pregabalin as the active ingredient. Excipients include preservatives (methyl parahydroxybenzoate E218, propyl parahydroxybenzoate E216) and other formulation components necessary to maintain stability, palatability, and microbiological quality (such as sweeteners, flavouring agents, and solvents like purified water; exact qualitative lists are specified in regional product characteristics).

Excipients of Clinical Relevance

• Methyl parahydroxybenzoate (E218): 1.3 mg per mL, associated with a risk of hypersensitivity reactions including delayed-type reactions.​

• Propyl parahydroxybenzoate (E216): 0.163 mg per mL, also associated with potential allergic reactions.​

Patients with known hypersensitivity to parabens or excipients listed in the product information should not receive this formulation.​

Therapeutic Indications

Pregabalin in the form of Lyrica oral solution is indicated for the same conditions as the capsule formulation, where authorized.

• Neuropathic pain in adults:

  • Peripheral neuropathic pain (e.g. painful diabetic neuropathy, post‑herpetic neuralgia).

  • Central neuropathic pain (e.g. following spinal cord injury).

• Epilepsy:

  • Adjunctive therapy in adults and certain paediatric age groups with partial‑onset seizures with or without secondary generalisation.

• Generalised anxiety disorder (GAD):

  • Treatment of GAD in adults (indication present in EU/UK labelling, not in all jurisdictions).

• Fibromyalgia (in specific markets such as the US and some others via the pregabalin brand, primarily capsule form; oral solution is pharmacologically equivalent where used):

Local regulatory approvals may differ; clinicians must refer to the national summary of product characteristics or approved product information.

Mechanism of Action and Pharmacodynamics

Pregabalin is a structural analogue of GABA but does not act directly on GABAAA or GABABB receptors nor does it influence GABA uptake or degradation. It binds with high affinity to the α22‑δ subunit of voltage‑gated calcium channels in the central nervous system, leading to reduced calcium influx into presynaptic neurons.

This binding decreases the release of several excitatory neurotransmitters, including glutamate, noradrenaline, substance P, and possibly others, thereby decreasing synaptic transmission in pain and seizure pathways. Clinically, this translates into reduced neuronal hyperexcitability, analgesic effects in neuropathic pain, anticonvulsant activity in partial‑onset seizures, and anxiolytic effects in generalised anxiety disorder.

Pharmacokinetics

Absorption

Pregabalin is rapidly absorbed after oral administration, with peak plasma concentrations generally achieved within 1 hour in the fasted state. The oral solution is bioequivalent to the capsule formulations on a milligram‑for‑milligram basis, with high oral bioavailability (≥ 90%) that is independent of dose. Food may reduce the rate but not the extent of absorption, slightly delaying TmaxTmax but not significantly altering overall exposure.

Distribution

Pregabalin exhibits low plasma protein binding (< 1%) and distributes widely into tissues. The apparent volume of distribution is approximately 0.5 L/kg, consistent with distribution into total body water.

Metabolism

Pregabalin undergoes negligible hepatic metabolism; the majority of the dose is excreted unchanged in urine. A minor proportion (about 1% of the dose) is metabolised to an N‑methylated derivative.

Elimination

Pregabalin is eliminated almost entirely by renal excretion with a mean elimination half‑life of approximately 6 hours in subjects with normal renal function. Clearance is directly proportional to creatinine clearance; therefore, systemic exposure increases with declining renal function. Pregabalin is efficiently removed by haemodialysis, with about 50% of the drug removed in 4 hours.

Posology and Method of Administration

General Dosing Principles

The total daily dose is normally divided into two or three doses per day, administered orally with or without food using an appropriate measuring device to ensure accurate volume. The oral solution allows flexible titration, particularly useful in populations requiring precise weight‑based dosing or in renal impairment.

Recommended Adult Doses (Oral Solution Equivalent)

Typical starting doses and titration schedules correspond to those of capsule formulations, adjusted in mL of solution (20 mg/mL).

• Neuropathic pain in adults:

  • Initial: 150 mg/day (7.5 mL/day), in two or three divided doses.​

  • May increase to 300 mg/day (15 mL/day) after 3–7 days, and to a maximum of 600 mg/day (30 mL/day) after an additional 7‑day interval, based on response and tolerability.

• Epilepsy (adjunctive therapy):

  • Usual initial dose: 150 mg/day (7.5 mL/day), titrated to 300–600 mg/day (15–30 mL/day) as tolerated.

• Generalised anxiety disorder:

  • Dose range: 150–600 mg/day (7.5–30 mL/day), divided into two or three doses; titrated according to clinical response.​

Renal Impairment and Haemodialysis

Dose must be adjusted according to creatinine clearance, with both the daily dose and dosing frequency modified in moderate‑to‑severe renal impairment. Patients on haemodialysis require supplemental doses following each 4‑hour dialysis session to maintain therapeutic levels.

Paediatric Dosing

Paediatric use is region‑specific; in the EU, pregabalin has been evaluated as adjunctive therapy in partial‑onset seizures in children ≥ 1 month of age in controlled trials. Dosing is typically weight‑based (e.g. 2.5–10 mg/kg/day up to defined maximum daily doses such as 150–600 mg/day depending on weight and age), expressed in equivalent mL of solution.

Discontinuation should occur gradually over at least 1 week to minimise withdrawal symptoms.

Clinical Efficacy

Neuropathic Pain

Multiple randomised controlled trials up to 13 weeks (BID) and 8 weeks (TID) have demonstrated that pregabalin significantly reduces pain scores in peripheral and central neuropathic pain, with improvements evident from week 1 and sustained throughout the study duration. In peripheral neuropathic pain trials, approximately 35% of pregabalin‑treated patients versus 18% on placebo achieved ≥ 50% reduction in pain intensity. In central neuropathic pain associated with spinal cord injury, about 22% on pregabalin versus 7% on placebo achieved this level of pain reduction.

Epilepsy (Adjunctive Therapy)

In three 12‑week controlled clinical trials in adults with partial‑onset seizures, pregabalin used as adjunctive therapy significantly reduced seizure frequency compared with placebo, with similar efficacy for BID and TID regimens. Responder rates (≥ 50% reduction in seizure frequency) increased with higher doses, within the 150–600 mg/day range.

Generalised Anxiety Disorder

Controlled trials in adults with generalised anxiety disorder showed that approximately 52% of pregabalin‑treated patients and 38% of placebo‑treated patients achieved ≥ 50% improvement in the Hamilton Anxiety Rating Scale (HAM‑A) from baseline to endpoint. Improvement in anxiety symptoms often appeared early (within the first week) and persisted throughout treatment.​

Fibromyalgia

In markets where pregabalin is approved for fibromyalgia, trials have demonstrated clinically meaningful reductions in pain and improvements in global assessments, although these data are primarily from capsule formulations and are extrapolated pharmacologically to the oral solution.

Safety Profile and Adverse Reactions

The overall safety profile of Lyrica oral solution mirrors that of capsule formulations.

Common Adverse Reactions

Very common and common adverse reactions include dizziness and somnolence, which are dose‑dependent and often start early in therapy. Other common events include increased appetite, weight gain, blurred vision, diplopia, ataxia, peripheral oedema, dry mouth, and headache.

Serious and Clinically Important Reactions

• Central nervous system depression and respiratory depression, especially with concomitant opioids or in patients with underlying respiratory compromise.

• Reduced lower gastrointestinal tract motility, including constipation, intestinal obstruction, and paralytic ileus, particularly when combined with opioids.​

• Hypersensitivity reactions including angioedema and anaphylaxis.

• Suicidal ideation and behaviour, as with other antiepileptic drugs; patients should be closely monitored for mood and behavioural changes.

• Withdrawal symptoms upon discontinuation, such as insomnia, headache, nausea, diarrhoea, flu‑like symptoms, anxiety, depression, pain, and, rarely, seizures.

Haematologic and Laboratory Changes

Uncommon haematologic changes include decreased white blood cell counts; elevations in liver enzymes (ALT, AST) have been observed. Laboratory and clinical monitoring should be guided by clinical status and comorbidities.

Adverse Reactions: Structured Overview

The table below summarises selected adverse reactions by system organ class (SOC) and frequency, as described for pregabalin (all oral forms, including 20 mg/mL solution where applicable).

Table 1. Selected Adverse Reactions to Pregabalin (All Oral Forms)

This table is illustrative and does not replace complete tabulated adverse reaction sections in official prescribing information.

Contraindications and Special Warnings

Contraindications

• Known hypersensitivity to pregabalin or any excipient of the formulation (including methyl and propyl parahydroxybenzoates).

Special Warnings and Precautions

• CNS depression and respiratory risk: Caution when co‑prescribing with opioids and other central depressants; cases of serious respiratory depression and increased risk of opioid‑related death have been described in epidemiological data.

• Renal impairment: Dose reduction is essential; accumulation may enhance adverse reactions including dizziness and somnolence.

• Suicidality: As with other antiepileptic drugs, a small increased risk of suicidal ideation; monitoring is recommended, particularly early in treatment or at dose changes.

• Withdrawal: Avoid abrupt discontinuation; taper over at least one week to reduce withdrawal symptoms and seizure risk.

• Abuse and dependence: There is emerging evidence of misuse and dependence potential, especially at high doses or in patients with a history of substance abuse.

Drug Interactions

Pregabalin shows minimal pharmacokinetic interaction because it is not significantly metabolised and does not inhibit or induce cytochrome P450 enzymes. However, pharmacodynamic interactions are clinically important.

• Concomitant use with opioids, benzodiazepines, or other CNS depressants may potentiate dizziness, somnolence, respiratory depression, and risk of overdose.

• No significant interaction has been shown with common antiepileptic drugs or oral antidiabetic agents at the pharmacokinetic level.

• Alcohol co‑administration enhances psychomotor impairment and sedation.

Use in Specific Populations

Pregnancy and Lactation

Pregabalin crosses the placenta and is present in breast milk. Animal studies show reproductive toxicity at exposures above human therapeutic levels, and limited human post‑marketing data suggest a potential risk of major congenital malformations, although data are not definitive. Use during pregnancy is generally not recommended unless the clinical benefit clearly outweighs potential risks, and effective contraception is advised for women of childbearing potential. Breastfeeding is typically not recommended during treatment or should be discontinued if therapy must continue.

Paediatric Population

Efficacy and safety in paediatric patients vary by indication and jurisdiction; for some indications (e.g. neuropathic pain, GAD) use is not established in children. For partial‑onset seizures, controlled data exist from trials in children aged 1 month to 16 years; overall, the safety profile is broadly similar to adults, though with some age‑specific differences in adverse event frequency.

Geriatric Population

Elderly patients may exhibit increased sensitivity to CNS and cardiovascular adverse effects such as dizziness, somnolence, and oedema, partly related to reduced renal function. Dose adjustments based on creatinine clearance are essential in this group.

Pharmaceutical Form, Storage, and Handling

Lyrica 20 mg/mL oral solution is supplied as a clear, usually colourless to slightly coloured solution in bottles with a child‑resistant closure and an oral dosing device. Storage conditions, including temperature limits and in‑use shelf‑life after opening, are specified in the national product information; typically, the product should be kept below a defined temperature and used within a set number of days after first opening. Patients should be instructed to use only the provided oral syringe or measuring device to ensure accurate dosing.

Summary and Clinical Considerations

Lyrica oral solution 20 mg/mL provides a flexible and bioequivalent alternative to pregabalin capsules for the management of neuropathic pain, partial‑onset seizures, and generalised anxiety disorder in appropriate patient populations. Its pharmacokinetic predictability, lack of significant hepatic metabolism, and availability as a liquid formulation favour use in patients with swallowing difficulties, those requiring weight‑based dosing, and in renal impairment where precise dose adjustment is necessary. Clinicians should, however, exercise careful attention to dose titration, renal function, CNS depressant co‑medication, and potential for withdrawal or misuse, using national prescribing information as the primary reference for region‑specific indications and dosing recommendations.