Specific situations to consider

Medication can affect both conception and foetal development.
For most medication, the effects on conception and foetal development are not well understood. It is crucial to have open discussions with women of childbearing age before initiating or prescribing medication and weigh the benefits against the risks. Preconception planning should include a medication review for those on long-term pain medication.
Pregabalin can impact foetal development,⁹² and similar considerations may apply to gabapentin.

For additional guidance, refer to:

Muscle aches and pains are common during perimenopause and menopause¹⁰⁹
In women aged 45 – 60 years presenting with new musculoskeletal pain consider perimenopause/ menopause as the cause and whether a trial of HRT is appropriate¹⁰⁹

Pain medication is metabolised either by the kidneys or the liver. Some medicines, such as codeine, are prodrugs that require metabolic conversion to an active form to be effective. Impaired renal or liver function can increase the risk of toxicity or reduce the effectiveness of certain pain medication.
NSAIDs, gabapentinoids and opioids may need adjustment of their doses or may be contraindicated in cases of significant renal or hepatic dysfunction.
check whether dosage adjustments are based on estimated glomerular filtration rate (eGFR) or creatinine clearance, for example gabapentin (see licence). For severe impairments, seek specialist advice.

Older adults often have multiple co-morbidities, higher levels of polypharmacy and increased sensitivity to commonly used medicines. This increases the risk of drug interactions as well as adverse effects.
Older adults may have weight loss and/or weigh less than 50kg, affecting prescribed dosages.
Older adults may be impacted by impaired renal or hepatic function, or medicines affecting the central nervous system. This can lead to increased risk of toxicity and adverse effects such as falls.
Use of medication with strong or very strong anticholinergic effects increases the risk of adverse effects, both cognitively as delirium, or in the peripheral effects such as blurred vision, urinary retention. Multiple medications compound this problem.
General guidance for prescribing in older adults is in the BNF- Prescribing in the elderly. Scottish Government Polypharmacy Guidance also contains detailed sections on prescribing in frailty and for older adults.
Recommended actions:
- Simplify regimens
- Rationalise medication as appropriate
- Reduce dose in line with hepatic or renal function
- Minimise anticholinergic burden using calculators such as mARS calculator

Many individuals with problematic substance use may also suffer from chronic pain and require treatment with pain medication.
The Faculty of Pain Medicine provides guidance for acute pain management.⁶⁶
Shared decision-making is crucial when standard analgesics are insufficient and medication with dependency risks is being considered.
Establish clear treatment goals and develop a strategy for discontinuation if clinical benefits are not realised.
Non-pharmacological strategies should be discussed.
Be aware of the risks associated with not prescribing, such as individuals obtaining illicit substances to manage their pain, which may increase the risk of accidental overdose. Seek advice from specialist services, including addiction services.
Consider prescribing naloxone (see section on naloxone).