Drug Interactions
Known and theoretical interactions between therapeutic peptides and common medications, supplements, and other compounds. Always inform your provider of everything you take.
Critical Safety Information
Severity Levels
Critical Interactions
These combinations are contraindicated or carry life-threatening risk. Do NOT combine without explicit specialist guidance.
Methylene blue is a potent MAO-A inhibitor. Combined with serotonergic drugs, it can precipitate serotonin syndrome.
Do NOT combine. Serotonin syndrome can be fatal. SSRIs should be discontinued at least 2 weeks before methylene blue administration (5 weeks for fluoxetine due to long half-life).
Same MAO-A inhibition mechanism as with SSRIs. Serotonin syndrome risk.
Contraindicated combination. Taper SNRI under provider supervision before starting methylene blue.
Serotonergic opioids combined with MAO inhibition create serotonin syndrome risk.
Avoid combination. Use non-serotonergic analgesics if pain management is needed.
Major Interactions
These combinations require careful monitoring, dose adjustments, or timing considerations. Discuss with your provider before combining.
GLP-1 agonists delay gastric emptying, reducing absorption rate and potentially lowering efficacy of oral contraceptives.
Consider switching to non-oral contraception or using backup methods during dose escalation phases. Discuss with your provider.
Delayed gastric emptying can alter warfarin absorption, leading to unpredictable INR fluctuations.
Increase INR monitoring frequency when starting, adjusting, or stopping GLP-1 therapy. Monitor weekly during dose changes.
Additive glucose-lowering effect increases hypoglycemia risk.
Proactive dose reduction of insulin or sulfonylurea is typically needed. Monitor blood glucose closely during initiation and dose escalation.
Testosterone increases hematocrit and may potentiate anticoagulant effects via changes in clotting factor synthesis.
Monitor INR frequently during TRT initiation. CBC with hematocrit every 3 months. Hematocrit above 54% requires intervention.
MK-677 increases blood glucose and insulin resistance, directly counteracting glucose-lowering medications.
Close glucose monitoring required. MK-677 may not be appropriate for diabetic patients. Discuss alternatives with your provider.
Moderate Interactions
These combinations may require awareness and periodic monitoring. Inform your provider if you are taking any of these combinations.
Slowed gastric emptying may affect levothyroxine absorption. Narrow therapeutic index drug.
Monitor TSH levels 6-8 weeks after starting GLP-1 therapy. Take levothyroxine on an empty stomach, ideally 60 minutes before GLP-1 medication.
Both can cause fluid retention. Combined use increases edema and cardiovascular strain risk.
Monitor blood pressure and weight. Watch for signs of fluid overload, especially in patients with cardiac history.
Testosterone may improve insulin sensitivity, potentially causing hypoglycemia in treated diabetics.
Monitor blood glucose closely when starting TRT. Diabetic medication doses may need downward adjustment.
MK-677 may transiently increase cortisol. Combined with corticosteroids, metabolic side effects compound.
Monitor blood glucose, blood pressure, and weight. Consider cortisol levels if symptoms develop.
BPC-157 may influence nitric oxide pathways and vascular function. Theoretical interaction with blood-thinning medications.
Limited human data. Monitor for unusual bruising or bleeding. Inform your provider if you are on anticoagulants.
Animal studies suggest BPC-157 modulates dopamine systems. May interact with medications for Parkinson's disease or psychiatric conditions.
Theoretical interaction based on animal data. Inform your provider of all medications if considering BPC-157.
Exogenous testosterone suppresses the HPG axis, directly opposing enclomiphene's mechanism of stimulating endogenous testosterone production.
These are generally used as alternatives, not together. Combining defeats the purpose of enclomiphene therapy.
PT-141 can transiently increase blood pressure. Combined with antihypertensives, unpredictable BP fluctuations may occur.
Monitor blood pressure before and after administration. Use with caution in patients on multiple antihypertensives.
Both affect vascular tone. Potential for additive hypotension after the initial hypertensive phase of PT-141.
Do not use within 24 hours of PDE5 inhibitors. Monitor blood pressure if combining.
How to Use This Information
Before starting any peptide: Make a complete list of all medications, supplements, and OTC drugs you take. Share this with your prescribing provider.
If you find a potential interaction: Do not stop any medication on your own. Contact your provider to discuss adjustments.
Supplements count: Many supplements (St. John's Wort, 5-HTP, SAMe) have serotonergic activity and can interact with peptides like methylene blue.
Timing matters: Some interactions can be managed by separating administration times. Your provider or pharmacist can advise on optimal timing.
Report new symptoms: If you experience any new or worsening symptoms after adding a compound, contact your provider immediately.
Interaction Not Listed?