Hey All,
I seem to be reacting very differently to EPH since I started taking 75mg of Nortriptyline (a Tricyclic Antidepressant) I'm taking for neuropathic pain. It's started making me anxious/nervous/jittery/twitchy/panicy when used in relatively small doses (50mg insufflated), after several months use without any problems.
Do you think that these side effects could be caused by the fact that they both inhibit the re-uptake of Dopamine, as well as Norepinephrine to a lesser extent? Nortriptyline has the following binding affinity (ki[nM]):
Dopamine: 3100 ki[nM]
Serotonin: 16.5 ki[nM]
Norepinephrine: 4.37ki[nM]
I used to take 100mg intranasally with no problems, some times using it multiple times per day. But now, even one hit of 50mg is making me feel awful (during each of the last 3 times), and each time I used it, I soon reached for some Propranolol, Diazepam and Oxycodone to calm down and subdue the jitters.
If it's not the Nortriptyline causing it, I can't think why else this would just start happening to me? Does my Nortriptyline 'theory' stack up, or can somebody prove it wrong and rule it out? It's a shame it's happening, because a little dab of EPH every now and then was very useful in waking me up and getting me going for the day.
I do have some MPA, but I'm not willing to try that until I figure out what's going on.
Since writing the aforementioned post and having just searched for drug interactions using various online services, I got the following information:
www.reference.medscape.com/drug-interactionchecker pulled up the following information when I checked for interactions between Nortriptyline and
Methylphenidate (using Methylphenidate as Ethylphenidate is not listed):
3 Interactions Found With Nortriptyline + Methylphenidate
Serious Interaction - Use Alternatives
Possible serious or life-threatening interaction. Monitor closely. Use alternatives if available.
Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
Significant Interaction - Monitor Closely
Nortriptyline increases sedation and Methylphenidate decreases sedation. Effect of interaction is not clear, use caution. Potential for interaction, monitor closely.
Minor Interaction
Methylphenidate increases effects of Nortriptyline by decreasing metabolism. Minor or non-significant interaction.
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http://www.drugs.com/interactions-check.php pulled up the following information when I checked for interactions between Nortriptyline and
Methylphenidate (using Methylphenidate as Ethylphenidate is not listed):
Moderate Interaction
MONITOR: The coadministration with Methylphenidate may increase the serum concentrations of tricyclic antidepressants (TCAs). Case reports involving primarily Methylphenidate and Imipramine have suggested favourable as well as unfavourable clinical effects from this combination. In vitro studies suggest that Methylphenidate may inhibit the metabolism of Imipramine and other TCAs, although the extent is probably subject to considerable interindividual variation.
MANAGEMENT: Pharmacologic response to TCAs should be monitored more closely whenever Methylphenidate (racemic) or Dexmethylphenidate (the more pharmacologically active d-enantiomer) is added to or withdrawn from therapy, and the TCA dosage adjusted as necessary.
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www.webmd.com/interaction-checker pulled up the following information when I checked for interactions between Nortriptyline and
Methylphenidate (using Methylphenidate as Ethylphenidate is not listed):
Serious - Use Alternative
Potential for serious interaction; regular monitoring by your doctor required or alternate medication may be needed. Tricyclic antidepressants may increase or decrease the effect of the other drug when taken in this combination
Significant - Monitor Closely
Potential for interaction. Nortriptyline oral increases and Methylphenidate decreases sedation and drowsiness.
Minor
Methylphenidate increases effects of Nortriptyline oral by slowing drug metabolism
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http://umm.edu/health/medical/drug-interaction-tool pulled up the following information when I checked for interactions between Nortriptyline and
Methylphenidate (using Methylphenidate as Ethylphenidate is not listed):
High Interaction Potential - Use Alternative
Treatment with both an amphetamine-like agent and a Tricyclic antidepressant may result in high blood pressure, and other effects on your heart and your nervous system. Using an amphetamine-like agent together with a Tricyclic antidepressant may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you.
Some examples of an amphetamine-like agent are Dextroamphetamine, Methylphenidate, or Phentermine. Examples of a Tricyclic antidepressant are Amitriptyline, Amoxapine, or Imipramine. If you are using both medicines together, your doctor may change the dose or how often you use one or both of the medicines. If you are already using an amphetamine-like agent and a Tricyclic antidepressant, call your doctor if you feel dizzy or Lightheaded, feel tired, have a headache, or have a faster than usual heart beat. Do not stop using your medicines without talking to your doctor first.
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http://www.cvs.com/drug/interaction-report pulled up the following information when I checked for interactions between Nortriptyline and
Methylphenidate (using Methylphenidate as Ethylphenidate is not listed):
Moderate Interaction
These drugs must be used together with close monitoring by your health care provider. Side effects may occur such as high blood pressure or fast heart rate, nervousness, palpitations, problems with sleep, severe headache, or other side effects.
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http://healthtools.aarp.org/drug-interactions pulled up the following information when I checked for interactions between Nortriptyline and
Methylphenidate (using Methylphenidate as Ethylphenidate is not listed):
Moderate Interaction
These drugs must be used together with close monitoring by your health care provider. Side effects may occur such as high blood pressure or fast heart rate, nervousness, palpitations, problems with sleep, severe headache, or other side effects.
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... So was I right in thinking this is down to the neurotransmitter interactions and I should avoid its use until I come off of the Nortriptyline, which will probably be in January when I change from Nortriptyline and Oxycodone to just Methadone, via my pain management consultant?