Short answer: These five compounded topical pain formulations — a triple-local-anaesthetic BLT cream, a capsaicin-counterirritant preparation, a gabapentin-hormone combination, an allantoin-soothing analgesic, and a high-strength lidocaine cream — address localised pain through different pharmacological routes at strengths and combinations no commercial product offers. Each is prepared as a non-sterile cream or gel for a named patient on a doctor’s prescription under Good Compounding Practice (GCP). Prescribers should note the methaemoglobinaemia risk with benzocaine, the systemic absorption ceiling for lidocaine, and the clinical-justification requirement for the gabapentin-hormone combination.
Why these five formulations — the compounding rationale
Commercial topical analgesic products are manufactured to fixed strengths, fixed combinations and fixed vehicles. When a prescriber needs a concentration outside that range, a combination of actives not available together, or a vehicle suited to a particular anatomical site, compounding is the formulation route. A Cochrane overview of topical analgesics for acute and chronic pain in adults concluded that topical NSAIDs, capsaicin and lidocaine each have a place in pain management, while the evidence for many compounded combinations remains limited and heterogeneous (Derry et al., Cochrane Database of Systematic Reviews, 2017; PMID 28497473). The five formulations below are prescribed on mechanistic rationale and clinical judgement, not on large-scale trial data for the specific combinations. Each preparation is made as a non-sterile cream or gel, for one named patient, on a registered doctor’s prescription, under Good Compounding Practice (GCP) — these are patient-specific preparations, not manufactured products.
Formulation 1 — Benzocaine 20%, Lidocaine 6%, Tetracaine 4%
This triple-local-anaesthetic combination — often referred to as BLT cream — places an ester anaesthetic (benzocaine, tetracaine) alongside an amide anaesthetic (lidocaine) to produce a depth of surface anaesthesia that a single agent at commercial strength does not achieve. It is typically prescribed for procedural pain involving intact skin — minor dermatological procedures, laser treatments, or needle-related procedures — where a commercial 4% lidocaine cream is insufficient. A clinical study of transdermal lidocaine demonstrated differential sensory nerve block after topical application, confirming that lidocaine delivered through the skin produces measurable anaesthetic effects (Sakai et al., Anesthesia and Analgesia, 2004; PMID 14693629).
The vehicle is critical: a pluronic lecithin organogel (PLO) or similar penetration-enhancing base is commonly selected to carry all three actives across the stratum corneum. Benzocaine and tetracaine are ester-type anaesthetics subject to hydrolysis; the base must be compatible with both ester and amide chemistry. The beyond-use date (BUD) is typically assigned at 30–90 days depending on water activity and stability data, consistent with non-sterile compounding practice.
This formulation carries a significant methaemoglobinaemia risk. Benzocaine is the most frequently reported topical anaesthetic associated with drug-induced methaemoglobinaemia. A retrospective review from the Mayo Clinic covering 28,478 transoesophageal echocardiograms documented benzocaine-induced methaemoglobinaemia with identifiable predisposing factors (Kane et al., Archives of Internal Medicine, 2007; PMID 17923598). A randomised study evaluating benzocaine alone and benzocaine plus tetracaine applied to oral mucosa found no methaemoglobin elevations in that setting, but the authors noted that risk depends on dose, site and patient factors (Wang et al., Clinical Therapeutics, 2017; PMID 28943117). A study of 10% and 20% benzocaine gels for acute toothache confirmed that 20% benzocaine is used clinically, though the application site was oral mucosa rather than intact skin (Hersh et al., Journal of the American Dental Association, 2013; PMID 23633700). Counselling points: apply to intact skin only; avoid broken or inflamed skin; do not apply to large surface areas; and counsel patients on signs of methaemoglobinaemia (cyanosis, dyspnoea, fatigue). The combination of three local anaesthetics increases cumulative systemic absorption risk.
Formulation 2 — Capsaicin 0.025%, Methylsalicylate 15%, Camphor 3.6%
This formulation combines a TRPV1 agonist (capsaicin) with two counterirritants (methylsalicylate and camphor) for localised musculoskeletal pain — muscle strains, joint discomfort, or focal inflammatory pain. A randomised, double-blind, placebo-controlled, multicentre study of a topical methyl salicylate and menthol patch in adult patients with mild to moderate muscle strain demonstrated efficacy for this class of counterirritant combination (Higashi et al., Clinical Therapeutics, 2010; PMID 20171409). A systematic review of topical therapies for knee osteoarthritis noted that counterirritant preparations have a role alongside NSAIDs and capsaicin (Rodriguez-Merchan, Postgraduate Medicine, 2018; PMID 30156934).
Capsaicin at 0.025% is a low-dose concentration intended for repeated daily application. A Cochrane review of high-concentration capsaicin for chronic neuropathic pain noted that capsaicin’s evidence base is strongest for neuropathic conditions, though the 0.025% concentration in this formulation targets musculoskeletal rather than neuropathic pain (Derry et al., Cochrane Database of Systematic Reviews, 2017; PMID 28085183). Earlier clinical trials confirmed capsaicin’s activity in postherpetic neuralgia (Bernstein et al., Journal of the American Academy of Dermatology, 1989; PMID 2768576) and painful diabetic neuropathy (Tandan et al., Diabetes Care, 1992; PMID 1737537).
The base should be an emollient cream that tolerates the lipophilic actives. Capsaicin is a skin irritant — patients should be counselled that the effect builds over days of consistent use, and hands must be washed thoroughly after application. Salicylate systemic absorption is a consideration with 15% methylsalicylate, particularly when applied to large areas or broken skin. Patients taking oral anticoagulants or with salicylate sensitivity should be identified before prescribing. Camphor is toxic if ingested. Local irritation — burning, redness — is common with capsaicin, particularly in the first one to two weeks.
Formulation 3 — Gabapentin 6%, Estriol 0.1%, Testosterone 0.1%
This combination requires clear clinical justification and carries specific safety considerations that prescribers should document in the formulation brief. Gabapentin 6% is a standard compounded topical concentration for localised neuropathic pain. A randomised controlled trial of topical gabapentin cream demonstrated effectiveness in treating pruritus in dialysis patients, confirming that topically applied gabapentin produces measurable clinical effects (Faghihi et al., Hemodialysis International, 2024; PMID 39164806). The addition of estriol 0.1% and testosterone 0.1% introduces hormonal actives alongside the neuropathic agent. One plausible scenario is a patient with localised neuropathic pain in a context of vulvovaginal or perineal tissue atrophy, where the prescriber intends to address both nerve-mediated pain and tissue trophism in a single topical application. Ultra-low-dose topical estriol has been studied for vulvovaginal atrophy, with clinical trial evidence supporting its local effects (Villa et al., Gynecological Endocrinology, 2020; PMID 31847628). Topical testosterone cream has been studied in menopausal women with hypoactive sexual desire disorder in a double-blind, randomised, placebo-controlled trial (El-Hage et al., Climacteric, 2007; PMID 17653960).
Gabapentin is water-soluble, while estriol and testosterone are lipophilic — this solubility difference requires careful vehicle selection. A PLO or emulsion base that can accommodate both hydrophilic and lipophilic actives is typically chosen. Flag: No published clinical evidence supports this specific three-actives combination as a unit. The prescriber should document the clinical rationale for combining a neuropathic agent with two hormones. Testosterone in a topical cream can transfer to others through skin contact — patients should be counselled to cover the application site and wash hands thoroughly. Hormonal actives require consideration of contraindications (e.g., hormone-sensitive conditions) and monitoring.
Formulation 4 — Allantoin 0.1%, Benzocaine 0.5%, Menthol 0.3%
This low-strength formulation combines a skin-soothing agent (allantoin) with a low-dose local anaesthetic (benzocaine 0.5%) and a cooling counterirritant (menthol 0.3%) for mild, localised skin discomfort where a gentle anaesthetic and soothing effect is desired without the high anaesthetic load of the BLT formulation. Allantoin has been studied for its wound-healing properties, with research demonstrating a profile of wound healing promotion in animal models (Araújo et al., Acta Cirúrgica Brasileira, 2010; PMID 20877959). A recent formulation study explored a lidocaine-allantoin hydrogel for wound healing applications, reflecting the rationale for combining allantoin with anaesthetic actives (Arpa et al., Pharmaceutics, 2025; PMID 41471121).
The low concentrations make this formulation suitable for an emollient cream base. Allantoin is poorly soluble in water — a suspension or emulsion base is appropriate. The BUD is typically assigned at 30–90 days for a non-sterile cream with preservative. At 0.5% benzocaine, the methaemoglobinaemia risk is substantially lower than the 20% concentration in Formulation 1, but is not zero — the same counselling on application site and frequency applies, with reduced intensity. Menthol can cause local irritation in sensitive individuals.
Formulation 5 — Lidocaine 10%
A 10% lidocaine topical preparation delivers a higher local anaesthetic concentration than the commercial 5% lidocaine patch, typically prescribed for focal neuropathic pain — postherpetic neuralgia, focal peripheral neuropathic pain syndromes — where the 5% patch strength is insufficient or a cream form is preferred for anatomical conformity. A Cochrane review of topical lidocaine for neuropathic pain in adults noted that while widely used in clinical practice, the quantity and quality of evidence was insufficient to support a strong recommendation (Derry et al., Cochrane Database of Systematic Reviews, 2014; PMID 25058164). A randomised, double-blind, placebo-controlled study of lidocaine patch 5% in focal peripheral neuropathic pain syndromes demonstrated efficacy at the 5% concentration (Meier et al., Pain, 2003; PMID 14581122).
The vehicle should enhance penetration to the dermal nerve targets — a PLO or liposomal base is commonly selected. Flag: 10% lidocaine is double the commercial patch strength, and systemic absorption is the primary safety concern. The maximum recommended lidocaine dose for topical application should not exceed 4.5 mg/kg in healthy adults. Patients should be counselled to apply to intact skin only, limit the total application area, and avoid applying heat to the site. Signs of systemic lidocaine toxicity — dizziness, tinnitus, perioral tingling — should be communicated. The prescriber should calculate the maximum daily exposure based on the application area and frequency.
Documentation and discussing a preparation with Lynnity
For each formulation, the prescription should include the named patient and prescriber details, active ingredients with exact strengths, dosage form (cream or gel), clinical rationale for compounding, anatomical site, known excipient exclusions, application instructions, and a review plan. For Formulations 1 and 3, the prescriber should document the safety monitoring plan — methaemoglobinaemia signs for the BLT cream, and hormone-related monitoring for the gabapentin-hormone combination.
Lynnity prepares non-sterile compounded topical formulations — creams and gels, including liposomal delivery forms — for named patients on a registered doctor’s prescription, under Good Compounding Practice (GCP). The pharmacy can advise on vehicle selection, excipient compatibility, stability and beyond-use dating for each combination, and can flag formulation concerns before the preparation is finalised. Where a prescriber is considering a related preparation — for example, a compounded pain cream incorporating ketamine or amitriptyline, or a liposomal delivery form of a single active — the pharmacy can prepare these on prescription as well.
Frequently asked questions
What is the methaemoglobinaemia risk with the BLT cream (Formulation 1)?
Benzocaine at 20% carries a documented methaemoglobinaemia risk. A retrospective review of 28,478 transoesophageal echocardiograms identified benzocaine as the most common topical anaesthetic associated with this adverse effect (Kane et al., 2007; PMID 17923598). The risk increases when benzocaine is combined with other local anaesthetics. Prescribers should limit the application area, avoid broken skin, and counsel patients on signs of methaemoglobinaemia.
Why combine gabapentin with estriol and testosterone in a single cream?
The clinical rationale should be documented by the prescriber. No published clinical evidence supports this specific three-actives combination as a unit. A plausible scenario is localised neuropathic pain in a context of tissue atrophy where the prescriber intends to address both nerve-mediated pain and tissue trophism. Topical gabapentin has clinical trial evidence for pruritus (Faghihi et al., 2024; PMID 39164806), and topical estriol has been studied for vulvovaginal atrophy (Villa et al., 2020; PMID 31847628).
Is 10% lidocaine cream safe for daily use?
Systemic absorption is the primary concern. The maximum recommended lidocaine dose for topical application should not exceed 4.5 mg/kg in healthy adults. Patients should apply to intact skin only, limit the total area, and avoid heat on the application site. The prescriber should calculate the maximum daily exposure based on application area and frequency. Signs of systemic toxicity include dizziness, tinnitus and perioral tingling.
What base is used for these compounded pain creams?
Vehicle selection depends on the actives. PLO (pluronic lecithin organogel) is commonly chosen for lipophilic actives and penetration enhancement. Liposomal delivery vehicles may be selected for actives where the skin’s lipid route is the target. For formulations combining hydrophilic and lipophilic actives — such as the gabapentin-hormone preparation — an emulsion base that accommodates both solubility profiles is required. The pharmacy advises on the appropriate base for each formulation.
Can these formulations be applied to broken skin?
No. All five formulations are intended for application to intact skin only. Broken or inflamed skin increases systemic absorption unpredictably, which is particularly hazardous for the high-strength local anaesthetic formulations (Formulations 1 and 5) and the methylsalicylate-containing preparation (Formulation 2). The prescriber should document the application site and confirm skin integrity before prescribing.
Reviewed by Vitthia Rama Murti, RPh (RPh 15632).
To discuss a patient-specific topical pain preparation — or to flag a formulation concern before prescribing — consult Lynnity’s compounding pharmacists, including Lead Pharmacist Vitthia Rama Murti, RPh (RPh 15632), at the compounding facility in MWE Commercial Park, Kepong, Kuala Lumpur.