Contents
- Using our advice
- Specific recommendations
- Agomelatine
- Alprazolam
- Amitriptyline
- Benperidol
- Chlordiazepoxide
- Chlorpromazine
- Cilostazol
- Cinacalcet
- Citalopram
- Clomipramine
- Clopidogrel
- Clozapine
- Dalteparin
- Diazepam
- Duloxetine
- Erlotinib
- Flecainide
- Fluvoxamine
- Haloperidol
- Heparin
- Imipramine
- Irinotecan
- Lorazepam
- Melatonin
- Methadone
- Mexiletine
- Nortriptyline
- Olanzapine
- Oxazepam
- Pentazocine
- Pifenidone
- Pomalidomide
- Propranolol
- Rasagiline
- Riluzole
- Riociguat
- Ropinirole
- Theophylline
- Tizanidine
- Warfarin
Using our advice
Some medicines are cleared from the body more quickly in smokers than in non-smokers. This can lead to increased adverse effects on stopping or reduced efficacy if starting (or restarting) smoking. In such individuals, dose adjustments and monitoring may be needed.
Before considering a specific interaction, ensure you are familiar with the following general advice:
Considering drug interactions with smoking
Specific recommendations
We provide advice for medicines where a pharmacokinetic interaction with smoking is included in the BNF, Stockley’s Interactions Checker (subscription required) or the manufacturer’s Summary of Product Characteristics. Note that in many cases, the pharmacokinetic interaction is not expected to be clinically significant in practice.
Consider dose adjustment
Be alert for increased adverse effects (such as dizziness, sedation, nausea) on stopping smoking and reduced efficacy on starting smoking.
If adverse effects occur, consider dose reduction.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Consider dose adjustment
Be alert for increased adverse effects (such as dizziness, sedation, extra-pyramidal symptoms) on stopping smoking and reduced efficacy on starting smoking.
If adverse effects occur, consider dose reduction. If smoking is restarted, titrate towards dosage taken while previously smoking.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Seek specialist advice
Smoking status changes are not expected to be clinically significant. However, individuals should inform their specialist if they start or stop smoking.
Monitoring and dose adjustment
Monitor parathyroid hormone levels; adjust dose if needed.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Some studies suggest an increased antiplatelet effect in smokers, but a clinically significant interaction is not established.
Seek urgent specialist advice
Smoking status changes have a clinically important effect. Individuals stopping or reducing cigarette smoking are at risk of severe toxicity. Those starting or resuming smoking may require dose titration. Individuals must tell their specialist if they plan to stop or start smoking.
Monitoring and dose adjustment
Dosage adjustment under specialist supervision will be needed.
If stopping smoking, take blood levels (in addition to any usual tests), and reduce dose as needed. Repeat blood levels after one week.
If starting (or restarting) smoking, take blood levels and titrate dose to maintain therapeutic effect. Repeat blood levels as needed.
Hospital admissions
Review smoking status on and during admission; arrange blood levels and dose reduction if smoking is significantly reduced or stopped.
Review changes if smoking is resumed.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Seek specialist advice
Changes in smoking status have a clinically important effect. Individuals are strongly advised to stop smoking before initiation and tell their specialist if their smoking status changes.
Dose adjustments
Dosage adjustment will be needed; seek specialist advice and supervision. Plasma levels are reduced in smokers versus non-smokers.
Rapid dose reduction is required on stopping smoking, to the usual dose for non-smokers. On starting (or restarting) smoking, the dose will need to be increased.
Consider dose adjustment
Be alert for dose-related adverse effects (such as dizziness, visual disturbances) on stopping smoking. If adverse effects occur, reduce the dose as necessary.
Consider dose adjustment
Be alert for dose-related adverse effects (such as nausea, tremor, nystagmus) on stopping smoking, and reduced efficacy on starting smoking.
Consider dose adjustment
Be alert for increased adverse effects (such as drowsiness, extra-pyramidal effects) on stopping smoking, and reduced efficacy on starting smoking.
If adverse effects occur, reduce dose by 25%. If smoking is restarted, titrate towards dosage taken while previously smoking.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Consider dose adjustment
Be alert for dose-related adverse effects (such as drowsiness, headache, dizziness) on stopping smoking, and reduced efficacy on starting smoking.
Adjust dose if necessary.
Consider dose adjustment
Be alert for signs of opioid toxicity on stopping smoking, and reduced efficacy on starting smoking.
If adverse effects occur, reduce the dose as necessary.
Consider dose adjustment
Be alert for signs of adverse effects (nausea, tremor, hypertension) on stopping smoking, and reduced efficacy on starting smoking.
Adjust the dose if necessary.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Consider dose adjustment
Be alert for increased adverse effects (such as dizziness, sedation, hypotension) on stopping smoking and reduced efficacy on starting smoking.
If adverse effects occur, reduce dose by 25%. If smoking is restarted, titrate towards dosage taken while previously smoking.
Monitoring
If possible, take plasma levels before changing smoking status, and repeat one week later.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Seek specialist advice
Plasma levels of pirfenidone are expected to be lower in smokers compared with non-smokers. Individuals are strongly advised to stop smoking before starting treatment.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Consider dose adjustment
Be alert for dose-related adverse effects (such as drowsiness, headache, dizziness) on stopping smoking, and reduced efficacy on starting smoking.
Adjust dose if necessary.
Consider dose adjustment
Be alert for increased adverse effects (such as dizziness, headache, nausea, diarrhoea) on stopping, and reduced efficacy on starting smoking.
If adverse effects occur, reduce the dose.
The manufacturer notes smokers may need a dose increase to the licensed maximum of 2.5mg three times daily.
Consider dose adjustment
Be alert for signs of adverse effects (such as nausea, dizziness) on stopping smoking, and reduced efficacy on starting smoking.
Adjust dose if necessary.
Consider dose adjustment
Changes in smoking status have a clinically important effect.
Individuals stopping or reducing cigarette smoking are at risk of toxicity or loss of clinical effect. Those starting or resuming smoking may require dose titration. Individuals must tell their specialist if they plan to stop or start smoking.
Dose adjustment
Consider a gradual dose reduction of 25-33% over one week on stopping smoking.
On starting (or restarting) smoking, the dose will need to be increased.
Monitoring
Theophylline plasma level should be monitored to inform further dose adjustments.
Hospital admissions
Be aware that individuals admitted to hospital, and unable to smoke, are at risk of theophylline toxicity. Further dose adjustment and monitoring will be required on discharge if the individual restarts smoking.
No routine action
Smoking status changes are not expected to be clinically relevant in most individuals.
Consider dose adjustment
Be alert for increased bleeding on stopping smoking, and reduced INR on starting smoking. Individuals should tell their clinicians if they plan to stop or start smoking.
Monitoring
Routine INR monitoring should detect any need for dose adjustments. Additional INR monitoring would not usually be needed unless appointments are infrequent.